Several members of group have had the horrible experience of accidentally connecting up a battery backwards and destroying an expensive radio. This little circuit was designed to use MOSFETs to prevent power reaching the radio if the input polarity is accidentally reversed. The power MOSFETS cost only about $3 each, and 2 of them will handle VHF mobile radios (50 watt output class); 4 of them will easily handle a 100W HF radio. We overdesigned this to avoid needing heatsinks and reduce voltage loss. There are no guarantees or warrantees but this circuit looks like a winner!

Cmax Battery cells are great, but they are too small for traditional busbars so a PCB busbar simplifies the process of building a 14s1p 48v battery pack. Project requires 2 PCBs, the busbar pcb and the BMS pcb.Here is the list of parts you'll need to complete this project: (Hyperlinks)14x C-MAX Cells w spacers 1x Buss PCB1x BMS PCB2x 60A BMS 7x M4 terminals 7x Standoffs 7x M4 screws 28x M5 nuts 1x Pair XT904x IDC socket connectors 4x IDC connectors Assembly required.Complete assembled Kit Coming soon

Cmax Battery cells are great, but they are too small for traditional busbars so a PCB busbar simplifies the process of building a 14s1p 48v battery pack. Project requires 2 PCBs, the busbar pcb and the BMS pcb.Here is the list of parts you'll need to complete this project: (Hyperlinks)14x C-MAX Cells w spacers 1x Buss PCB1x BMS PCB2x 60A BMS 7x M4 terminals 7x Standoffs 7x M4 screws 28x M5 nuts 1x Pair XT904x IDC socket connectors 4x IDC connectors Assembly required.Complete assembled Kit Coming soonVideo

The UnoCart-2600 is an open source SD-card multicart for the Atari 2600. Use the joystick or the SELECT/RESET keys to navigate the SD card and select a title to play.SD card should be formatted as FAT or FAT32.The UnoCart-2600 can emulate most banking schemes with ROM sizes up to 64k and RAM sizes up to 32k.The releases of new firmware can be found on DirtyHairy's branch04/15/2021-----------------I've had alot of life happenings, but here is the Full size SD version of the UnoCart 2600 i was working on. Any issues, please post, but things seem to be working fine under testing.The cartridge case shown is a cartridge case design i have been working on. Once time allows in life and it's complete, it will be posted online. The PCB should work in a standard Atari 2600 Cartridge case with some mods for the SD card slot.

8K RAM module for "Model T" computers.Instead of the TE-1544210 leadframe, here is another way to do the legs using gold-plated brass wire.https://github.com/bkw777/Model_T_RAM/blob/main/doc/DIP_PCB_legs.mdhttps://github.com/bkw777/Model_T_RAM/blob/main/doc/DIP_PCB_legs.md

In this project, we will create an infrared remote control for your TV, cable box, DVR, Blu-ray, or another similar consumer electronic device. The remote control is operated by a webpage interface. The Raspberry Pi serves the webpage over your local Wi-Fi network. You can access it on your PC, laptop, tablet, or phone as long as it is connected to your local Wi-Fi network.You can learn more about this project at https://github.com/cyborg5/qtpyhat and a full learning guide will be available on Adafruit.com.

Http://GitHub.com/doudar/SmartSpin2KSmartSpin2KHardware (3d Printed) and Software Project that uses an ESP32 and stepper motor to control spin bikes that have a resistance knob. The initial target was to use it with Zwift: stationary bike up hills and feel the burn.Optionally, the SmartSpin2K project has also progressed to the point of where it's useful without the hardware as a BLE device multiplexer, heart rate to watt converter (estimator), and proprietary BLE device to normal FTMS protocol converter using only the redily availiable ~$6 ESP32 devkit.BackgroundI travel for a living and some hotels I stay at have spin bikes. I started carrying my own power meter pedals for the spin bikes so I could ride Zwift, but the experience just isn't the same without automatic resistance on the hills. Then one day I was looking down at that simple to turn knob and I had a thought - With the power meter pedals attached, almost everything is already in place on this $300 spin bike to turn it into the equivalent of a $3,000 computer controlled smart bike! And so here we are....https://www.instructables.com/Spin-Bike-Controller/

For use with:https://www.pcbway.com/project/shareproject/WP_2_ROM_IC_Card.htmlTo build: Discard 2 pins off the 1x40 1.27mm pin header to leave 1x38 pins. Suggestion: Cut right in the middle of the 39th pin instead of trying to cut between the 38th and 39th pin. Then sand the rough end down a little if desired. If you try to cut in between the pins on this header, you're likely to break enough plastic that the 38th pin falls out. Solder the remaining 1x38 1.27mm pin header. Solder the 2x8 2.54mm pin header. Cut 2 strips of 14 pins from the 40-pin 2.54mm pin header. Solder to the bottom surface. Cut 2 pins from the remaining 2.54mm pins. Solder the pins together on one side to make a male jumper. To use: For a ROM card: Set all 4 jumpers to ROM. Insert the male jumper into the write-enable holes in the ROM IC Card. If your programmer doesn't specificaly support your chip's actual part number, try the generic flash part number 29F020.For a Breakout/ROM card: Set all 4 jumpers to ROM on the programming adapter. Jumper R/W to /WE_IC on the breakout card. Jumper /CE1 to /WE_IC on the breakoutr card. Remove the jumper from GND to /DET on the breakout card. After programming: Remove the jumper from R/W to /WE_IC.For a RAM card: Set all 4 jumpers to RAM. If your programmer doesn't specically support your chip's actual part number, try the generic SRAM part number 628128.https://www.pcbway.com/project/shareproject/WP_2_ROM_IC_Card.html

It seems all breadboards/protoboards are for narrow DIP IC's... with wider chips, you're left with just a couple connection points on each side. Bummer! So I made my own extra-wide version that will give you 3 on one side and 4 on the other! (Or for regular DIPs, you get 5 on each side!)

I saw this on the Youtube channel "Adrian's Digital Basement", but could not find where to get one. So I created one myself.This is a great tool for debugging vintage computers or any system with 40-pin chips (or the same form factor like Nano's), or other wide DIP's like 32, 28, and 24 pin -- you can even build various versions. Just remove the chip from the target system, plug this in its place, and insert the chip in the socket on this adapter. If needed, stack extra sockets for sufficient board clearance. The jumpers on the 2-wide headers for each pin can be removed to disconnect that pin form the circuit -- or you can swap pins, jumper it to ground or Vcc or inject any signal needed for debugging, without modifying the board or the original chip.Additional headers allow you to connect a logic analyzer or scope to any needed pins.Note: Be sure to install the 2 headers on the underside first, since they need to be soldered on the top side, underneath the IC socket!

Gerber zip file includes Acad Eagle v9.6.2 board, schemaic and Bill of Materials

IntroductionThis is a companion board to my EPROM Emulator NG (see my other shared projects). With a few solder bridge jumpers, you can configure this PCB is to perform one of the following functions:use my emulator or a 28 pin EPROM memory like the 2764-27512 in place of 2364 ROM commonly used in Commodore 64 or VIC-20use my emulator to emulate 24 pin memory like the 2716 or 2732 (the emulator can do it with the default 28 pin adapter, but power has to be provided externally, this PCB solves the issue).Since the minimum order is 5 PCBs you can create yourself a set of useful adapters.How to assemble.1. Configure the PCB for either 2364 support or 2716/32 supportIn this example, I soldered all the bridges on the left-hand side to configure the board to support 2716/2732 memory. 2. (optional) If you are using the PCB as a 2364 to 2764 adapter you can solder the pull-up resistors for line A13-A15 note: if you are using the adapter with my emulator those pull-ups are not required as the emulator has those built-in.3. Solder the 2x 12 pin headers.To help with the soldering process, I insert the headers into a breadboard before soldering:Pay extra attention as you insert the pins into the PCB, the 2x 12pin headers should be on the left set of holes!4. Trim the right-hand-side header after soldering to create space for the 28 pin socket5. Solder the 28pin socket6. Your new adapter is ready to use.

This is a new release of the Amiga 4000 ROMY.

In this video we take a circuit from the March 2021 ARRL Magazine (Ham radio) designed by John Burnley. It is a polarity tester for your wall wart power supplies. Are center negative or center positive? You can plug the output into this board and know instantly.

In late Summer of 2018, Perifractic and I began collaboration on a project that would become the VIC-II2 Card (pronounced VIC-TWO-SQUARED). Our shared love of Commodore 64 and retro technology made it an easy partnering. Perifractic had already performed a conversion of an NTSC version of the C64 to PAL as part of his Retro Recipes YouTube channel, but he was looking for a method to more easily switch between the two modes. Why would you want to do that? In some cases, software that was written to run on PAL may not work properly on NTSC, and vice-versa. The manual modification requires swapping out the VIC-II chip (MOS 6567 for PAL and MOS 6569 for NTSC), the timing crystal (17.734475 MHz for PAL and 14.31818 MHz for NTSC), and then changing jumper settings on the motherboard so that the C64 knows in which mode it should be running. So, Perifractic posed the question, “What if we could switch all of those modifications at once, with both options installed?” We began discussing ideas and sketching ideas on how to make this happen, given the technical and physical constraints of the types of C64 machines people would be installing our solution into. I came up with this early sketch as a starting point…?It’s fanciful to look at in retrospect, particularly the naive suggestion that the signals of the VIC-II chips could survive routing through a flat or ribbon cable of that length (what were we thinking?). I built a dozen versions of this board before we settled on the final one, meandering between a logical digital switching solution, to a mechanical switch (literally a 10p2t push switch), to the final analog relay solution. We also went through both through-hole and SMD versions of many of the components, settling eventually on a solution that could be hand-soldered by most semi-technical enthusiasts.The journey from that original sketch to a fully working 1.0 version took about eight months of part-time work. Perifractic was very patient with me as I tried (and failed) to get individual portions of the system to work. The solution is simple, but it’s not perfect. We would prefer to have gotten the digital switching option to work rather than use analog relays, and that a mechanical toggle switch doesn’t have to be used, as that implies that either a hole be drilled in the case, or a “pig-tail” with the switch attached dangle out an already-exposed hole in the rear of the case. The solution also requires a bit more modification than most casual C64 users may want to undertake. While we’d love this to be a simple plug-n-play solution, it is not… RF shields must be desoldered and removed, components and jumpers must be desoldered with pins soldered in to replace them… this is not as simple as plugging in a cartridge.But the VIC-II2 card does offer something that many C64 lovers have wanted: an easily-switchable NTSC or PAL solution that uses hardware rather than software emulation. I’m sure that we’ll eventually solve the digital switching problem, possibly modifying solutions where the RESTORE key has been used to toggle ROM versions. For now, enjoy the fruits of our labor, and get ready for a fun and interesting install.1STAGE, Sean Harrington, Technical DesignerOctober 11, 2019