My version of the Tim Escobedo Ugly Face. It raucous square wave distortion that is more synth in a box than traditional fuzz. It uses a 555 oscillator grated by the guitar signal. The frequency of oscillation is controlled by the Frequency knob. The threshold knob controls the point of oscillation. The envelope knob controls the amount of frequency sweep based on the input dynamic. Listen to a demo here: https://youtu.be/SX_MTmnqspY

The Audio Tone Burst Generator produces a periodic burst of tone at a User-selected audio frequency at a User-selected repetition rate. It can also be used as a regular audio generator. The frequency range is 20Hz to 10 KHz. It is used for measuring the time delay of a piece of audio equipment. Modern audio equipment may use some fancy digital processing which may introduce a noticeable delay in the sound. You may want to measure the time delay in a piece of audio equipment in the following situations. 1. If you use your own sound system with your TV and your sound system does some fancy digital processing the delay may be long enough that you will notice that the actor’s mouth movements are not synchronized with the sound. That is very distracting. For television applications, the Advanced Television Systems Committee recommends that audio should lead video by no more than 15 milliseconds and audio should lag video by no more than 45 milliseconds. See https://en.wikipedia.org/wiki/Audio-to-video_synchronization 2. In a sound re-enforcement system such as may be used in a meeting, you can increase the feedback margin by several dB by using a frequency scaler (pitch changer) to change the sound going to the sound re-enforcement system (amplifier and speakers). The sound being fed back is at an ever increasing or decreasing frequency so it doesn’t howl. If you limit the frequency scaling to +/- 5% the people speaking will not notice. Indeed, you should lower the pitch of the person’s voice, not raise it. When we talk, bone-conduction to our ears acts as a low pass filter so our voice sounds lower to us than to the people we are talking to. Thus we are less likely to notice that our speech has been frequency scaled down a little. The frequency scaler will have some time delay. If delay is more than 50ms we will hear that as an echo and most people will be distracted by that. Indeed, if the delay is around 200ms most people will try to talk slower (and slower) in order to “catch up” with themselves. This can provide a great deal of amusement for everyone except the person who is talking. The amount of delay depends on several factors including age. See this article on Delayed Auditory Feedback (DAF): https://en.wikipedia.org/wiki/Delayed_Auditory_Feedback. A delay of 200ms seems to be the worst: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4477042/ . Frequency scaling is difficult to do in real time. The best frequency scaler that I have heard is in my old Stanton STR8-80 turntable. It has a control to vary the speed of the turntable and then a frequency scaler (pitch shifter) to restore the pitch of the music. You can speed up and slow down the music without changing its pitch. The turntable also has an auxiliary audio input which is inserted before the pitch shifter. When you use the turntable speed control it obviously cannot change the speed of the auxiliary audio input so you are left with a very fine pitch shifter (frequency scaler). In measuring the time delay of the Stanton STR8-80 I discovered that the delay is different for different frequencies but in all cases is less than 15ms. This would be a good frequency scaler for a sound re-enforcement system for a meeting. Some microphone mixers have special effects which include pitch shifters. I have not tested them. If you are using a microphone mixer because you are recording the meeting you want to send the clean mix to the recorder and the frequency-scaled mix to the amp and speakers. Perhaps a good realtime frequency scaler can be done with a Raspberry Pi. If so, you can use the Audio Tone Burst Generator to make sure the delay is within an acceptable limit. The Audio Tone Burst Generator uses an MSP430G2402 microcontroller to control an Analog Devices AD9833 and displays the User selections on a 16x2 LCD. From the AD9833 datasheet (https://www.analog.com/media/en/technical-documentation/data-sheets/AD9833.pdf): "The AD9833 is a low power, programmable waveform generator capable of producing sine, triangular, and square wave outputs. Waveform generation is required in various types of sensing, actuation, and time domain reflectometry (TDR) applications. The output frequency and phase are software programmable, allowing easy tuning. No external components are needed. The frequency registers are 28 bits wide: with a 25 MHz clock rate, resolution of 0.1 Hz can be achieved; with a 1 MHz clock rate, the AD9833 can be tuned to 0.004 Hz resolution." This is how to use the Audio Tone Burst Generator. F/D Switch: Switch between Burst, Frequency, and Sweep Modes; Press and hold for about 2 seconds (then release) to change modes; Comes up in Burst Mode In Burst Mode: INC - Press and release to increase the time between bursts - Press and hold for about 2 seconds to keep increasing the time between bursts; release to stop DEC - Press and release to decrement the time Between bursts - Press and hold for about 2 seconds to keep decreasing the time between bursts; release to stop MODE - Press and release to toggle the time step between bursts to either 1 ms or 10 ms In Frequency Mode: INC - Press and release to increase the frequency - Press and hold for about 2 seconds to keep increasing the frequency; release to stop DEC - Press and release to decrement the frequency - Press and hold for about 2 seconds to keep decreasing the frequency; release to stop MODE - Press and release to toggle the frequency step between 10 Hz and 100 Hz In Sweep Mode: It sweeps between 20Hz and 10KHz until you press and hold the F/D switch. The Header pin labeled “Sync” is for triggering an oscilloscope to measure the delay through the equipment you are testing. In Burst Mode it goes low at the beginning of the burst and goes high at the end of the burst. In Sweep mode it goes low at the beginning of the sweep (20 Hz) and goes high at 1KHz (about 800 ms). The sweep from 20 Hz to 10KHz takes about 8 seconds. The skill level for stuffing the board is: Intermediate. Make sure you use a temperature-controlled soldering iron. I use a temperature of 340 degrees Celsius. And don’t inhale the solder fumes. If you don’t have a fume hood use a fan to blow the solder fumes away from you. To compile the source code and download it into the microcontrollers I use Texas Instruments Code Composer Studio. It is free and is on this page: https://www.ti.com/tool/MSP-EXP430G2ET where you can get the versions for Windows, Linux and macOS. The direct link to the current version for Windows is: https://software-dl.ti.com/ccs/esd/CCSv10/CCS_10_4_0/exports/CCS10.4.0.00006_win64.zip . The skill level to use Code Composer Studio is: Advanced. (Maybe Really Advanced). Notes 1. When you get the Launchpad, if you want to use it by itself to become familiar with it and Code Composer Studio and you want to use the crystal, you have to jumper the two sets of pads labeled R5 and R7. Here is the MSP-EXP430G2ET User Guide: http://www.ti.com/lit/pdf/slau772. 2. To program the MSG430G2402 you connect the Tone Burst Generator to the Launchpad with three of these wires: Breadboard Jumper Wires 10cm Dupont Wire, Female to Female. When you use it this way you cannot have a MSP430G2xxx in the Launchpad’s socket. The part is on the Tone Burst Generator Board.To make it run standalone remove the three wires and use a header plug to connect the /RES and /Reset pins on the header (on the Tone Burst Board). 3. The audio outputs are: Line Level, Microphone Level, and Speaker. The Speaker output does not produce much power. It is there so you can listen to the Generator when you are using it. If the Line and Mic outputs are not exactly the levels that you need you can change R15, R15, and/or R17. I have posted more information (which you need) and more pictures on my Web site: www.jmargolin.com/newprojects/tone-burst/tone-burst.htm This includes the source code. The source code is complete. It does not require any libraries other than the ones that come in Code Composer Studio. Happy Tone Bursting. Jed MargolinVirginia City HighlandsNevada

This gadget imitates a 1 euro coin or coins of a similar size that are required for a shopping cart. The circuit board can easily be attached to a key ring and is a perfect companion for on the go. Electrotechnical basics can also be learned with the help of the circuit board. The footprints of various ICs can also be seen on it! Have fun with it!

About the projectI'm studying a master's in electronic instrumentation. In this covid period, we work on a prototype to solve a new contingency in a course of my university (Universidad Nacional Autonoma de Méxco). This prototype for the first time was thinking to joint art and technology and experiment with this area, however, the development of the project will be used to study a relation between the pollution (PM and CO2) on air and the health of the people.Problem: Deterioration of air quality due to the industrial/social process because of the constant demand for the creation of products and services.Response to the problem: The human being is visualized as a mobile being that interacts with an environment that can be toxic or beneficial to his health. In such a way that the human being is seen as a mobile "sensor" that can map the health of a city in relation to pollution (PM particles and/or CO2/CO concentration) in the air.While qualitatively one can feel tired, say that the air is heavy or visualize a cloud of smog in the distance that does not allow to observe the volcanoes near the CDMX, Mexico, the use of a monitor that transforms these expressions to a quantitative form of what we are experiencing in our daily activities in the streets of the city.Thus, a portable air quality monitor that registers the air quality in the zones that an individual travels through in a daily day is a preliminary idea. - Technical: Numerical and analytical visualization of the data as a record of air quality in city halls/colonies. This can be a history of how much the city is degrading or how much the city is improving in a given period. Prototype on printed model3D Model, Top View3D Model, Bottom View-Artistic: Due to the constant rain of data to which we are exposed, many times the numbers are just scribbles on screens which simply move with the movement of a finger. In such a way that to visualize the air quality records we think of a structure like a small heart that has movement and color, both determined by the levels that the mobile being detects, i.e., polluted air means a slow movement or a dark color because the oxygenation of the blood is not done properly (TDB/TBC). This piece is also thought of as a response to "imagining new displays", that is, we always think of screens as a means of visualization for human beings, however, the use of a mobile object that changes color or accelerates or decreases its movement would allow someone to see the effect that in this case the air has on our body.3D model printed

* * HARDWARE OVERVIEW * *The uTerm2-S (micro Term2 stand-alone) is an easy to build multi-emulation RS232 terminal using an ESP32-Wroom-32 module and the great FabGL library (http://www.fabglib.org). More, using an ESP32 gives the opportunity to use the uTerm2-S in a lot of different ways easily using the Arduino IDE with the ESP32 core.These the main specs of uTerm2-S:RS232 serial port;VGA output;"transparent" port for a serial-USB adapter (as in the uTerm-S);secondary serial port for ESP32 programming using a serial-USB adapter;RTS/CTS support between the RS232 and the "transparent" port (as in the uTerm-S);on board power supply;colors, graphics and sounds capabilities (FabGL library);multi language keyboard support (FabGL library);various terminal emulations (FabGL library);PS/2 connectors for keyboard and mouse;on board amplifier for an external speaker.In the following image a uTerm2-S (previous PCB revision) connected to a common PC speaker:This one is the final board:THE COM-USB2 (J3) CONNECTOR (TRANSPARENT PORT)The uTerm2-S has a "transparent" port for an USB-serial adapter (as in the uTerm-S), so you can e.g. use XMODEM to exchange files with a PC (running a terminal emulator that supports XMODEM file transfer) while the uTerm2-S is in use.Both the "mixed" power supply scenarios (USB-serial adapter not powered from USB but uTerm2-S powered and vice-versa) are managed by the HW, so you don't need to worry about it.In the following photo a serial-USB adapter is connected with a cable to the transparent COM-USB2 (J3) port:This allows to use two keyboards and two monitors in the "same" time (one keyboard and monitor attached directly to the uTerm2-S, and another keyboard and monitor of the terminal emulator on a PC connected with the serial-USB).Please note that the COM-USB2 (J3) port supports the RTS/CTS HW handshaking, so both RTS/CTS signals are needed on the serial-USB adapter.In the following image a common CP2102 based serial-USB adapter with the RTS/CTS signals connected:The following table shows how to connect the serial-USB adapter to J3:NOTE: The signals assignment is the same of the SER-USB (J3) connector of the uTerm-S.THE PRG-USB1 (J2) CONNECTOR (PROGRAMMING PORT)The PRG-USB1 (J2) connector is use to program the ESP32 using a serial-USB adapter (it is recommended to use a model that supports the default 921600 bit/s upload speed, like the CP2102 based adapters).Both the "mixed" power supply scenarios (USB-serial adapter not powered from USB but uTerm2-S powered and vice-versa) are managed by the HW, so you don't need to worry about it.For more information about the programming procedure see the "HOW TO PROGRAM THE ESP32" paragraph.THE SPK (J9) CONNECTORThe SPK (J9) connector is used to attach an optional speaker (4/16 Ohm). I've used a salvaged PC speaker.OTHER CONNECTORSThe remaining connectors are obvious. PS/2 KB (J5) and PS/2 MOUSE (J4) are for a PS/2 keyboard and an optional PS/2 mouse. Please note that many USB keyboards (and USB mouses too) have a PS/2 compatible chip inside so can be used with the well known "green adapter":The VGA (J1) connector is for a VGA monitor, and the RS232 (J8) connector is the RS232 serial port for the Host. The maximum speed is 115200 bps (it is the maximum speed of the MAX232 RS232 driver).The DC-IN (J2) is the power in connector. It is recommended to use a 9V 1A DC power supply.THE RTS-HS (SW3) SWITCHThe uTerm2-S has both the RTS/CTS signals for HW handshaking between the RS232 serial port (J8) connector (for the Host) and the COM-USB2 (J3) connector (the "transparent port" for the terminal emulation SW on a PC), so it can be used for file exchange.To clarify the following image shows a block diagram of the serial ports of the uTerm2-S:On the COM-USB2 (J3) side the RTS signal is used by the terminal emulation SW on a PC to put in a wait state the communication if the RX buffer on the PC side is full. The CTS signal is an input that allows the Host to do the same if the input buffer on the Host side is full. Because a PC is typically a lot more fast than a retro-system it can be handy set the RTS signal to an "always ready to accept" state (on the PC side). In this case the RTS-HS switch (SW3) is used to turn on or off the RTS handshaking.When turned off, the Host connected to the serial port will see the RST line always active (RTS and CTS are active "Low" signals). This can be handy in some situations.The RTS-HS switch has no influence on the CTS signal.THE RST KEY (SW2)The RST key (SW2) is used to reset the ESP32 module.THE DFLT KEY (SW1)The DFLT key (SW1) is used to reset all the terminal parameters to default values. To activate this function you have to press down the DFLT key and, while holding it down until the reset is complete, press and release the RST key (SW2) to reset the uTerm2-S.NOTE: the DFLT key must be enabled inside the AnsiTerminal sketch (see the "HOW TO PROGRAM THE ESP32 (J2/PROG-USB1 CONNECTOR)" paragraph) to make it work.* * SOFTWARE OVERVIEW * *The uTerm2-S is designed to use the FabGL library, so you need to install Arduino IDE and the ESP32 core at first.Then you have to install the FabGL library. Because there are a lot of tutorials around I'll not give more details here (i.e. see the Demos and Tutorials section on the FabGL site) about how set up the "toolchain".HOW TO PROGRAM THE ESP32The uTerm2-S can be programmed using the Arduino IDE as a common ESP32 board (having the needed circuitry for auto uploading):You just need to use the PRG-USB1 (J2) connector with a serial-USB adapter:The following table shows how to connect the serial-USB adapter to PRG-USB1 (J2):NOTE: You can use the same adapter/cable for both programming (thru J2) and communicating with the transparent port (thru J3) as the J2 and J3 connection tables have a compatible signals assignment.To flash the terminal FW you have to open the AnsiTerminal "sketch" from the Examples of the FabGL library:Remember to change at first the line containing:#define USERESETPIN 0to:#define USERESETPIN 1to enable the DFLT key:Now you can compile and flash the AnsiTerminal sketch.NOTE 1: Don't enable the HW RTS/CTS handshaking on the "Flow Control" terminal setting panel as the HW handshaking is reserved for the COM-USB2 (J3) "transparent" connector (see the "THE RTS-HS SWITCH" paragraph), and the relative GPIOs are not used for that.NOTE 2: The maximum terminal serial speed cannot exceed 115200 bps.GAMESIn the Examples directory of the FabGL library there are some games that can be run with the uTerm2-S too.Here Space Invaders:and Classic Racer:and don't forget to connect the speaker!* * CREDITS * *The FabGL library was developed by Fabrizio Di Vittorio (http://www.fabglib.org).NOTE: All the updates and the details to build it are in the uTerm2-S main page here: https://hackaday.io/project/181583

This Project requested by our local schools for STEM robotics . they wanted a Drone that utilize the familiar Arduino Environment and Development board they already at hand with promising results . this board integrate power distribution , sensors and pins for various drone project the students will be doing.Essentially turns an arduino board into an all in one flight controller , this is package with its own Ground station and applicationthis board is the 2nd alteration developmentVideoWebsite:http://synerflight.com/2021/08/07/stem/Quick documentation:http://synerflight.com/quick-guide-synerduino/

SUMMARY You can pair the Compute Module capabilities with this carrier board to offer the exact hardware and final package that you need for your custom application having the flexibility of using the raspberry pi in a more diverse form factor of your choice.Video shows the boot-up test where the transistor enables boot-up from the eMMC flash indicated by the LED turning off at the edge. The red LED that lights up when Ethernet connection is made at the end of the video is an indication of half-duplex (Data packets are sent back and forth), which is a feature in the LAN chip, help to see whether communication is been initiated or not and in which mode, FULL DUPLEX or HALF DUPLEX.DESCRIBTION OF PROJECTIf you have not heard of the Raspberry Pi Compute Module, it’s basically a Linux computer with the form factor of a laptop RAM stick.The on-board eMMC also eliminates the need for an external micro SD card, which makes the Compute Module perfect for designing Raspberry Pi based products and more.The Compute Module is designed for use in custom devices where capabilities of the Pi are desired but do not meet unique form factor or I/O requirements. The Compute Module is a Raspberry Pi that has been shrunk down to fit on a smaller form factor with two high-speed, high-density 100-pin mezzanine connectors.The Raspberry Pi Compute Module is derived from the CM3 board but offers better thermal behaviour under load. That’s possible because of the Broadcom’s 64-bit BCM2837B0 application processor, which was also used in last year’s Raspberry Pi 3B+, and 1GB of LPDDR2 RAM. The CM3+ draws heat away from the processor faster than the CM3 and is rated to support temperatures between -20°C and 70°C (-4°F and 158°F).You can then pair the compute capabilities with a carrier board of your choice to offer the exact hardware and final package that you need for your custom application.With this in mind, the compute module is primarily designed for those who are going to create their own PCB.So here we are with this new design to allow the use of the fantastic BCM chip on the CM.The compute module on sale, appears to be lacking in terms of popularity compared to the traditional Raspberry Pi Model A and B. As a result, there aren’t many open source hardware projects out there based on it. Trying to design you own board, you will notice limited resources available to you.Creating your own PCB allows you the flexibility to add components that you need and also get rid of any you do not need to save yourself money. This PCB makes use of the fantastic LAN9512 USB-to-Ethernet chip.This is a 4 layered PCB board that I designed, used, and it works perfectly with no issues at all, and if you need HDMI connection, you can add it much easier to allow displays to be connected depending on your project. You will get this sleek PCB with 4mm mounting holes for your project (Photo below) newest version and the design files for editing if you wish to add few other parts, I used Altium software, which should be easy to convert to other software like eagle etc., for editing.I ordered the first designed version from PCBWay shown in the photos (below) and it was perfectly made and works great, test shows all USB and Ethernet port works great and I build some cool IOT projects with it. The second edited module (Data packs attached) gives users the mounting holes for easy mount for your project.COMPUTE MODULE 3+First Version I designed below and used for the test, with results shown below.The compute module I used has the 16GB eMMC flash device which is the equivalent of SD card in raspberry pi integrated on it, great and very reliable.What can you do with this? am glad you asked. This allows users to use the raspberry pi core in a more flexible form factor, can be use in custom devices where capabilities of the pi are desired but do not meet the unique form factor.LAN CHIP CONNECTION TESTOPERATION TEST RESULTSADVANTAGES> It provides 10/100Base-T ethernet connectivity to the compute module> On-board eMMC flash device to upload your image to> RTC timer to keep up accurate date and time> Easy programmable CM3 to use on the moduleSPECIFICATIONSoC: Broadcom BCM2837B0, Cortex-A53 (ARMv8) 64-bit SoC @ 1.2GHzMemory: 1GB LPDDR2 SDRAM8GB/16GB/32GB eMMC Flash memoryRJ45 Ethernet connectivityOnboard Gigabit Ethernet PHY supporting IEEE15882 × USB 2.0 interfacePCIe Gen 2 x1 interface28 GPIO signalsDual-display support at resolutions up to 4K, video decode at up to 4Kp60Multimedia supports H.265 (4Kp60 decode); H.264 (1080p60 decode, 1080p30 encode); OpenGL ES 3.0 graphicsWell, what the Compute Module is able to achieve is largely bound by the carrier board that you pair it with! With the right carrier board, you’ll have virtually limitless possibilities thanks to the module’s flexibility. My carrier board provides me with remote access to my connected devices all around the world, you can edit the carrier board to suit you need.Microchip LAN9512 DetailsThe LAN9512 and LAN9514 are fully-integrated, hi-speed USB 2.0 hub and high-performance 10 / 100 Ethernet controllers. They are specifically designed to provide system architects with a low-cost, power-efficient, small-footprint USB to Ethernet and multi-port USB connectivity solution in a single package. SMSC’s LAN9512 / 9514 contain a hi-speed USB 2.0 hub with two (LAN9512) or four (LAN9514) fully-integrated downstream USB 2.0 PHYs, an integrated upstream USB 2.0 PHY, a 10 / 100 Ethernet MAC / PHY controller, and an EEPROM controller. The LAN9512 / 9514 simplifies system design by leveraging the existing USB stack, reducing PCB footprint by up to 65% compared to discrete competitive solutions.The external EEPROM is optional depending on your use need, the chip works fine with or without the external EEPROM.FEATURESNetDetach low-power technology allows reduction of system power up to 25% by enabling the host CPU to enter a low-power state when the Ethernet connection is inactive.Built-in ± 8 kV / 15 kV contact/air discharge ESD protection on both USB and Ethernet PHYsUniClock technology simplifies the clocking scheme and reduces system BOM cost by using a single 25 MHz crystal for both USB and Ethernet connectivity - without the need for extra components when adding USB hubsFully-integrated 2/4-port hi-speed USB 2.0 hub and 10 / 100 Ethernet controllersTHIS CAN BE UPGRADED TO ACCOMMODATE ANY PART YOU NEED WHICH MAY INCLUDE, HDMI, DISPLAY FFC CONNECTOR, FTDI ETC.Designed files are available on request.Enjoy a happy IOT project build.If you have any questions hit me up hereadios!!!!

This PCB brings the "S" into the SFB (Smart Filament Buffer). It combines a Filament-Buffer needed for multi material 3D printing with an integrated run-out sensor which tells your 3D printer whether it's out of printing material.Utilizing an Arduino Nano, an OLED display and Hall-Sensors it's a breeze to set up and configure according to your needs.Read all about the project in the description linked on Thingiverse.I created this PCB for everyone who'd like to build his/her own SFB without the hassle of wiring it up on a piece of prototype board.A very short video on how it works can be found here:

This board solves flickering effect problem for LEDs.Project video: https://youtu.be/kAI77ma01wEOne color LED version: https://www.pcbway.com/project/shareproject/LED_Brightness_Controller_with_555_Timer.htmlProject video:

The Github site to download the code and design files is available here: https://github.com/mike-rankin/ESP32_USB-C_Power_SupplyA video of the project is available here: https://www.youtube.com/watch?v=B5UGXPlmMGQThe idea for this ESP32 usb-c power supply project came to me when I discovered that components exist that communicate to parts inside usb-c wall chargers. These parts send out a request to the charger asking it to deliver specific voltage and current values if possible. Small chargers cannot deliver as much power as the larger ones. The small navigation button allows the user to select values with the top button as a power switch.Hardware design instead of software is my strength so Larry Bank (https://github.com/bitbank2) was kind enough to write the software. I've changed a few things around and damaged it so it is still work in progress.To upload an Arduino sketch to the board it is connected to a pc using a USB-C cable but the output is only ever +5V. When the board is plugged into a dedicated usb-c charger like the 60 watt apple one that I use, multiple voltages and current options are available. Text on the back of your charger will let you know what values are available.A +5V LDO with a maximum input of 36V provides power to the CP2104N USB-C interface chip. Current consumption is so low for this part that and LDO will not get warm.Because the ESP32 current draw a few hundred milliamps, an earlier revision using an LCD was too hot when +15v and +20V was selected. (power=voltage x current) A small switching buck power supply with a maximum input of +40V now runs cool.Measuring current draw at every voltage would be ideal so I've chosen the INA199 because at this time it is the only component that I can find in stock. Right now it's performance not good so I will try and find something better for the next revision.

Lurking for a simple digital filter for my modular synthesizer, I got aware of the existence of a library capable of turning any arduino board into a wavetable oscillator... WHAAAT!I could not resist (how could I! Korg DW8000 is still one of my favourite synthesizers!) and immediately started developing a pcb for an eurorack wavetable oscillator based on Mozzi library.In the following I will show you how I designed my voltage controlled wavetable oscillator prototype for modular systems.FeaturesI designed the board layout with very specific functions in mind, but given the possibility to upload any custom sketch/firmware, this can be seen as a base for a lot of different modulars (i.e. Mozzi oscillators, but not only that).In general the PCB is designed to handle:- up to 4 potentiometers, for direct control of parameters- up to 3 external control voltages (0-5V, overvoltage protected)- 1 trimmer for fine, permanent settings (i.e. V/oct scaling)- up to 7 digital pins configurable as inputs or outputs- small footprint- eurorack power supply ready (2x8 pins IDC connector)- built-in Midi IN circuit- open firmwareThe community around the Mozzi library made an incredible work in these years. Not only the libray itself is very deep, but there are also utilities that can help make this thing even more interesting. In example: what about the possibiliry to ?create your own wavetables from wav files! O_O'Hardware Design Choices and CircuitsUsing arduino and Mozzi library for this project makes the pure sound generation "simple", but some boundary/slave circuit are needed to accomodate an arduino into a module that will coexist with other, external modules.A necessary precaution concerns input voltages: Arduino sends and receives "logical" inputs, therefore it is limited to the 0-5 V dc range both in input and output. To overcome this, I have included three voltage limiting circuits, one for each analog inputs left for CVs. This circuit can be done in various ways: frequency divider, use of a Zener diode, use of Schottky diodes... just to cite the most common. The circuit adopted in this board is made with schottky diodes as per Doepfer specifications. The circuit lowers any voltage above 5V (in a modular system we can expect up to 10-12V for a control voltage), "stops" any negative voltage, and transfers variable voltages below the 5V threshold voltage.Another built-in circuit is MIDI input. The circuit is built around a common optocoupler (6N138) and it's shown above. To optimize the code, I generally prefer to use hardware serial instead of software serial. This project makes no exception. Being that the MIDI circuit interfere with arduino Rx pin even when nothing is connected, I placed a simple jumper, labelled "JRx". This has to be removed/switched every time you want to upload a new sketch and then inserted back in for MIDI to work. A little annoying, but keeping the code lean has priority in a project that deals with waves generation (you will get used at that, don't worry!).To use Mozzi library at its best, audio output is made compatible with both STANDARD PLUS and HIFI modes.In HIFI mode, bit depth is increased and effective noise floor reduced. It does not have an effect on distortion or unwanted PWM frequency interference, anyway.To have your hardware ready for HIFI mode, populate R1, R2, R3 and C1 with:R0 - 1M ohmR1 - 1M ohmR2 - 3.9K ohmC1 - 4.7nFTo have your hardware ready for STANDARD PLUS mode, instead, populate R2 with a 330 ohm resistor and leave the other components unpopulated.Setting HIFI mode asks for both the described components in the output stage, but also for a software mod. Go to "Documents\Arduino\libraries\Mozzi-master", open "mozzi_config.h" and change#define AUDIO_MODE STANDARD//#define AUDIO_MODE HIFIto//#define AUDIO_MODE STANDARD#define AUDIO_MODE HIFIIn this shield, all arduino nano analog inputs are wired: four are dedicated to the front panel potentiometers, three can be used for external analog inputs (with overvoltage protection) and the latest (A7) is hard-wired to an utility trimmer.A total of seven digital inputs are accessible for user functions.Please notice that the sketch I wrote cannot be uploaded into an Arduino nano with ATmega168 processor because of memory limits. Be sure to buy a nano with ATmega328P.Even if the board is equipped with a full 8x2 IDC connector, being 100% digital this projects is powered by +5V only.The SketchI wrote a sketch as a starting point for future implementations and features.Being this intended to be the oscillator of a modular synthesizer (mine :) ), you will not find a whole synth coded, but a steady, two waves generator.So, what I coded here are two detunable, wavetable assignable, pure oscillators. Selectable waves are sine, triangular, saw, square, and white noise, in any combination.The oscillator pitch can be controlled by MIDI or voltage.In the followings the functions of potentiometers, buttons and incoming MIDI messages.PotentiometersThe first potentiometer POT_A0 controls the relative detuning of wave two.The second potentiometer (POT_A1) acts on the relative gain of the two waves: fully clockwise you will hear wave one only, fully counter-clockwise wave two only. Any other position results in a relative blend of the two waves.The third potentiometer (POT_A2) controls the global output gain.The fourth potentiometer (POT_A3) affects the main tuning.The built-in trimmer is used for V/oct scaling.MIDIIf a MIDI note-on messages is received, waves are tuned accordingly.A gate out signal is output at D8 pin when a MIDI note-on (HIGH) or note-off (LOW) message is received, accordingly.Default MIDI channel is set to 1 and can be easily changed by uploading a new firmware.Both MIDI note-on and pitchbend are supported.MIDI note priority is set to latest. It is possible to code other note priorities (lowest, highest) but the actual code does not support them.Control VoltagesThis wavetable oscillator is not MIDI-only, but also voltage controlled. By sending a 0 - 5V signal to analog input A6 both waves will tune accordingly. As said, the trimpot acts on V/oct scaling.A simple voltage control over wave two detuning is coded: if a reading other than 5V is available at analog input "A4", it is summed to POT_A0 reading and toghether detune the oscillator.MIDI note-on message has the priority over voltage pitch control, and disables it. In order to re-activate CV pitch control, disconnect the MIDI cable then reset the microcontroller.Please notice that I had not the possibility to test adeguately the CV part of the code (I have not a keyboard, nor a controller adopting the V/Oct standard at the moment), but I will in the near future.ButtonsTwo non-latching buttons are used to indipendently select wavetables on the fly. Wavetable one can be changed by pressing a normally open button/switch shorting D2 to ground; wavetable two with a button on D3. You cycle through waves at every button press. Waves are sine, triangular, saw, square and white noise in any combination, but they can be easily changed modifying the sketch.Two non latching buttons connected to D4 and D5 are used to set the pitch height of each wave. You can transpose the base pitch up two octaves and down one octave.The full code can be found HERE (Github).Please notice that I have left some code lines for functions I planned and implemented, but in the end I have disabled. In example, I had planned some sort of modulation for at least one of the two waves (vibrato) to give some additional movement to the base sound. It's disabled, but still there for future reference :)BOMThe board is intended to be mounted perpendicular to the front panel. If your case is not deep enought, you can lock the board on the case bottom and use wires to gain electrical connection with elements (potentiometers, buttons, jacks and so on) on the front panel.All components values are silkscreened on the PCB to make assembly easier.Follows the list of components:Microcontrollers- 1x Arduino nano (ATmega 328p, NOT ATmega168p)Capacitors- 1x 100n ceramic- 1x 4.7n ceramicResistors, Potentiometers, Trimmers- 4x 10K ohm potentiometer- 1x 10k ohm trimmer- 5x 1000 ohm resistor- 1x 200 ohm resistor- 1x 330 ohm resistor- 2x 1M metal film resistor (HIFI mode)- 1x 3900 metal film ohm (HIFI mode)- 1x 330 ohm (standard_plus mode)Diodes and optocouplers- 1x 6N138- 6x BAT42 Schottky- 1x 1N4148 Others- 1x DIN5 MIDI connector- 1x 2x8 IDC connector- 1x PCB switchFuture Plans - Paraphony!Realizing a single, two waves oscillator was incredibly fun. When I start thinking at what could be next, I cannot stop to figure that a polifonic chain of such wavetable oscillators would be awesome... one of the next projects could well be a midi controller for a stack* of wavetable oscillators like this, or eventually for any CV oscillator!* stack reasonably could mean four: I have these MCP4728 4 channels DACs on their way to me ... ;)

For a long time, I wanted to create a unique device to observe the presence of varying hazardous gases for a breadth of applications such as air quality monitoring and gas leak detection. Thus, I decided to develop this project.First of all, to elicit assiduous gas measuring results, I chose to utilize these MQ series gas sensors by connecting them to the Arduino Nano:MQ-2MQ-3MQ-4MQ-6MQ-9After choosing gas sensors for my device, I decided to control its settings and features with an IR remote control. Hence, I connected an IR remote receiver module to the Arduino Nano. Then, to display generated gas measurements, I used an ST7789 IPS screen.Finally, I added a buzzer and a 5mm common anode RGB LED to get notified when gases reach dangerous levels.As you may have known, the toxic gas compound manufactured by Joker (Joker Venom or Laughing Gas) is considered remarkably dangerous in DC Universe. Hence, I shaped my device inspired by Joker's appearance in comics as a reminder of the detrimental effects of gases.After completing wiring on a breadboard and testing the code, I designed my Joker-inspired PCB to complete my project. It became a stylish and intriguing addition to my workplace as an effective apparatus to monitor the presence of hazardous gases :)Step 1: Designing and soldering the Joker Remote Gas Station PCBBefore prototyping my PCB design, I tested all connections and wiring with the Arduino Nano on the breadboard.Then, I designed the Joker Remote Gas Station PCB by using KiCad. I attached the Gerber file of the PCB below, so if you want, you can order this PCB from PCBWay to create a fitting and apt apparatus to observe the presence of hazardous gases and get notified when they reach dangerous levels - inspired by malicious Joker :)First of all, by utilizing a soldering iron, I attached Arduino Nano, IR receiver module, MQ-2 gas sensor, MQ-3 gas sensor, MQ-4 gas sensor, MQ-6 gas sensor, MQ-9 gas sensor, headers (female), buzzer, 5mm common anode RGB LED, 220Ω resistors, 20K resistors, and power jack.Component list on the PCB:A1 (Arduino Nano)S1 (Headers for ST7789 IPS Screen)IR1 (IR Receiver Module)MQ2 (MQ-2 Gas Sensor)MQ3 (MQ-3 Gas Sensor)MQ4 (MQ-4 Gas Sensor)MQ6 (MQ-6 Gas Sensor)MQ9 (MQ-9 Gas Sensor)BZ1 (Buzzer)D1 (5mm Common Anode RGB LED)R1, R2, R3, R4, R5, R6, R7 (220Ω Resistor)R8, R9, R10, R11, R12 (20K Resistor)J1 (Power Jack)J2 (Headers for External Battery)Step 2: Programming Arduino Nano and setting up componentsDownload the required library to be able to control the IR receiver module:Arduino-IRremote | LibraryDownload the required libraries to be able to use the ST7789 240x240 IPS screen:Arduino_ST7789_Fast | LibraryAdafruit_GFX | Library? Include the required libraries.? Define the IR receiver module pin and settings.#include <Adafruit_GFX.h> #include <Arduino_ST7789_Fast.h> #include <IRremote.h> // Define the IR receiver module pin and settings. #define RECV_PIN 2 IRrecv irrecv(RECV_PIN); decode_results results; ? By executing the IRrecvDemo.ino file in Examples, obtain the required IR codes from the IR remote control and define them.#define up 0xFF18E7 #define down 0xFF4AB5 #define right 0xFF5AA5 #define left 0xFF10EF #define ok 0xFF38C7 ? Define the ST7789 240x240 IPS display settings.#define TFT_DC 10 #define TFT_RST 9 #define SCR_WD 240 #define SCR_HT 240 ? To display images on the ST7789 screen, convert them to .c files by using this image converter below:ImageConverter (UTFT)You can download the converted images I used in Downloads - gas.c, lethal.c, and toxic.c.? Include the converted images.#include "gas.c" #include "lethal.c" #include "toxic.c" ? Initiate the ST7789 240x240 IPS display.Arduino_ST7789 tft = Arduino_ST7789(TFT_DC, TFT_RST); ? Initiate the IR receiver module.? Start and clear the ST7789 240x240 IPS display. irrecv.enableIRIn(); tft.init(SCR_WD, SCR_HT); tft.fillScreen(RGBto565(235, 46, 0)); ? In the read_IR_controls function, collect IR codes from the IR remote control when transmitted.void read_IR_controls(){ // Read received IR codes from the IR remote control.if(irrecv.decode(&results)){ IR_codeValue = results.value; irrecv.resume(); delay(500); }else{ IR_codeValue = 0; } } ? In the collect_Data function, get gas measurements produced by MQ series gas sensors - MQ-2, MQ-3, MQ-4, MQ-6, and MQ-9.void collect_Data(){ // Get variables generated by the gas sensors. mq_2_val = analogRead(mq_2); mq_3_val = analogRead(mq_3); mq_4_val = analogRead(mq_4); mq_6_val = analogRead(mq_6); mq_9_val = analogRead(mq_9); } ? In the interface function, print the interface with menu options.void interface(){ // Print interface with menu options. tft.setTextColor(RGBto565(0, 38, 153), RGBto565(235, 46, 0)); tft.setTextSize(4); tft.setCursor(75, 25); tft.println("MQ-2"); tft.setCursor(75, 65); tft.println("MQ-3"); tft.setCursor(75, 105); tft.println("MQ-4"); tft.setCursor(75, 145); tft.println("MQ-6"); tft.setCursor(75, 185); tft.println("MQ-9"); } ? In the change_menu_options function, increase or decrease the option number by using the IR remote control buttons - Up and Down - to switch between menu options on the interface.void change_menu_options(){ // Increase or decrease the option number using the IR remote control buttons.if(IR_codeValue == up) selected--; if(IR_codeValue == down) selected++; if(selected < 0) selected = 5; if(selected > 5) selected = 1; delay(100); // Depending on the selected option number, change the boolean status.switch(selected){case 1: mq2 = true; mq3 = false; mq4 = false; mq6 = false; mq9 = false; break; case 2: mq2 = false; mq3 = true; mq4 = false; mq6 = false; mq9 = false; break; case 3: mq2 = false; mq3 = false; mq4 = true; mq6 = false; mq9 = false; break; case 4: mq2 = false; mq3 = false; mq4 = false; mq6 = true; mq9 = false; break; case 5: mq2 = false; mq3 = false; mq4 = false; mq6 = false; mq9 = true; break; } } Step 2.1: Displaying the presence of hazardous gasesTo detect the presence of hazardous gases, I utilized these five MQ series gas sensors:MQ-2MQ-3MQ-4MQ-6MQ-9MQ-2 gas sensor has a high sensitivity to LPG, Propane, and Hydrogen, also can be used to detect Methane and other combustible steam.MQ-3 gas sensor has a high sensitivity to Alcohol and has good resistance to gasoline, smoke, and vapor. This sensor can detect Alcohol with different concentrations.MQ-4 gas sensor has a high sensitivity to Methane, Propane, and Butane. This sensor can detect different combustible gases.MQ-6 gas sensor has a high sensitivity to Propane, Butane, and LPG, also response to Natural gas. This sensor can detect different combustible gases such as Natural gas, colorless flammable gaseous hydrocarbon consisting primarily of Methane and Ethane.MQ-9 gas sensor has a high sensitivity to Carbon Monoxide, Methane, and LPG. This sensor can detect different gases containing CO and combustible gases.As expected, after being connected to Arduino Nano, each sensor generates different value ranges depending on the amount of detectable hazardous gases.After testing, I assigned these levels below for each sensor empirically. Change them after testing your sensors if required.mq_2_val < 600 ? Low 600 < mq_2_val < 700 ? Moderate mq_2_val >= 700 ? Dangerous mq_3_val < 650 ? Low 650 < mq_3_val < 800 ? Moderate mq_3_val >= 800 ? Dangerous mq_4_val < 450 ? Low 450 < mq_4_val < 600 ? Moderate mq_4_val >= 600 ? Dangerous mq_6_val < 500 ? Low 500 < mq_6_val < 650 ? Moderate mq_6_val >= 650 ? Dangerous mq_9_val < 700 ? Low 700 < mq_9_val < 850 ? Moderate mq_9_val >= 850 ? Dangerous ? If a menu option is selected using the Up and Down buttons, highlight its name on the interface.? After being selected, if a menu option is activated using the OK button:? Collect and display the gas measurement value of the selected MQ series sensor with the converted images.? If the gas measurement value is Low according to the assigned levels, adjust the RGB LED to green.? If the gas measurement value is Moderate according to the assigned levels, adjust the RGB LED to yellow.? If the gas measurement value is Dangerous according to the assigned levels, adjust the RGB LED to red and turn on the buzzer to notify the user.? By pressing the Left button, return to the interface. if(mq2){ do{ tft.setTextColor(RGBto565(0, 38, 153), WHITE); tft.setTextSize(4); tft.setCursor(75, 25); tft.println("MQ-2"); if(IR_codeValue == ok){ activated = true; tft.fillScreen(WHITE); while(activated){ read_IR_controls(); // Print data: collect_Data(); tft.setCursor(75, 25); tft.setTextColor(BLACK, WHITE); tft.setTextSize(4); tft.print(F("MQ-2")); tft.drawImageF(30, 80, 40, 40, gas); tft.drawImageF(100, 80, 40, 40, lethal); tft.drawImageF(170, 80, 40, 40, toxic); tft.setCursor(60, 160); tft.setTextSize(7); tft.print(mq_2_val); // Check gas status:if(mq_2_val < 600){ adjustColor(0, 255, 0); } else if(mq_2_val >= 600 && mq_2_val < 700){ adjustColor(255, 255, 0); } else if(mq_2_val >= 700){ adjustColor(255, 0, 0); tone(buzzer, 500, 1000); } // Exit and Close:if(IR_codeValue == left){ activated = false; tft.fillScreen(RGBto565(235, 46, 0)); adjustColor(0, 0, 0); noTone(buzzer); } } } }while(!mq2); } ... Step 2.2: Fixing the timer0_pin_port errorUnfortunately, when using the IR remote library and the tone library, the Arduino IDE throws the timer0_pin_port error. The error occurs because both libraries try to use the timer by declaring the same name - Timer2.To fix this issue, open the boarddefs.h or IRremoteBoardDefs.h file depending on the IR remote library version. Then, change IR_USE_TIMER2 to IR_USE_TIMER1 for Arduino Nano.Connections and Adjustments// Connections // Arduino Nano : // IR Receiver Module // D2 --------------------------- S // ST7789 240x240 IPS // GND --------------------------- GND // 3.3V -------------------------- VCC // D13 --------------------------- SCL // D11 --------------------------- SDA // D9 --------------------------- RES // D10 --------------------------- DC // MQ-2 Air Quality Sensor // A0 --------------------------- S // MQ-3 Air Quality Sensor // A1 --------------------------- S // MQ-4 Air Quality Sensor // A2 --------------------------- S // MQ-6 Air Quality Sensor // A3 --------------------------- S // MQ-9 Air Quality Sensor // A4 --------------------------- S // 5mm Common Anode RGB LED // D3 --------------------------- R // D5 --------------------------- G // D6 --------------------------- B // Buzzer // D7 --------------------------- + After completing soldering and uploading the code, I attached all remaining components to the board via headers - ST7789 240x240 IPS screen.Unluckily, even though Arduino Nano works at 5V, the current provided by Nano is not enough for five MQ series gas sensors to get heated and generate accurate gas measurements. Thus, I added a power jack (J1) and a connector (J2) to my PCB design to supply the sensors with an external battery (5V).Modes and Features???? The device shows five different MQ series sensors as menu options on the interface to display their gas measurements individually:MQ-2MQ-3MQ-4MQ-6MQ-9???? The device allows the user to switch between MQ series sensors (menu options) to observe their gas measurements via the IR remote control:Up Button ? Go UpDown Button ? Go DownOK Button ? Activate???? After activating any MQ series sensors by pressing the OK button of the IR remote control to display their gas measurements, the device lets the user return to the interface by pressing the Left button.?? MQ Series Sensors (Menu Options)???? If the MQ-2 option is selected and activated, the device shows its hazardous gas measurement value.???? Depending on the assigned measurement levels for the selected sensor (Step 2.1), the device adjusts the RGB LED:Green ? LowYellow ? ModerateRed ? Dangerous???? The device turns on the buzzer if the hazardous gas measurement value is Dangerous according to the assigned levels.???? If the MQ-3 option is selected and activated, the device shows its hazardous gas measurement value.???? Depending on the assigned measurement levels for the selected sensor (Step 2.1), the device adjusts the RGB LED:Green ? LowYellow ? ModerateRed ? Dangerous???? The device turns on the buzzer if the hazardous gas measurement value is Dangerous according to the assigned levels.???? If the MQ-4 option is selected and activated, the device shows its hazardous gas measurement value.???? Depending on the assigned measurement levels for the selected sensor (Step 2.1), the device adjusts the RGB LED:Green ? LowYellow ? ModerateRed ? Dangerous???? The device turns on the buzzer if the hazardous gas measurement value is Dangerous according to the assigned levels.???? If the MQ-6 option is selected and activated, the device shows its hazardous gas measurement value.???? Depending on the assigned measurement levels for the selected sensor (Step 2.1), the device adjusts the RGB LED:Green ? LowYellow ? ModerateRed ? Dangerous???? The device turns on the buzzer if the hazardous gas measurement value is Dangerous according to the assigned levels.???? If the MQ-9 option is selected and activated, the device shows its hazardous gas measurement value.???? Depending on the assigned measurement levels for the selected sensor (Step 2.1), the device adjusts the RGB LED:Green ? LowYellow ? ModerateRed ? Dangerous???? The device turns on the buzzer if the hazardous gas measurement value is Dangerous according to the assigned levels.Videos and ConclusionAfter completing all steps above, I placed the device on my desk by utilizing a plastic easel as an efficient assistant to detect the presence of hazardous gases in my workplace. It works impeccably :)