Introduction

Hello everyone! Today I present FloppyBoard, a small development board similar to Arduino but designed to be more affordable and feature-rich. Its dimensions are comparable to a standard Arduino. This is the first version, which was also used in my Pet Feeder project. I later created three more versions with improvements.

This article is necessary for the realization of the Pet Feeder, a highly appreciated project that has gained interest from those who want to replicate it. For more details, you can find information on the project on my YouTube channel.

Production and Assembly

After receiving the PCBs, I purchased the components separately and hand-soldered them. I chose this approach to save money and because I find manual assembly an enjoyable activity.

Programming the FloppyBoard

There are two methods to program the FloppyBoard:

• A Nucleo Board with an integrated ST-Link
• A separate ST-Link programmer

In both cases, the connection is made through the programming pins, correctly wired with jumper cables. With the ST-Link, it is also possible to perform debugging and access literally all the features and settings of the microcontroller, which in this case is an STM32G030F6P6.

Connecting to the PC

Connect the ST-Link board to the computer using a USB-A to USB-mini cable.

• Connect the FloppyBoard programming pins to the ST-Link.
• Provide power to the FloppyBoard (the ST-Link does not supply power directly).
• Use STM32CubeIDE to write and upload the firmware to the board.

It is really that easy to connect the FloppyBoard to a PC and program it. In version 3, I added the ability to do everything via USB without needing an ST-Link, but it does not offer the same level of control. For example, debugging is not possible.

First Test: Blinking LED

To verify that the board is functioning correctly, I wrote a simple program to turn an LED on and off, similar to the LED 13 on Arduino. After compiling and uploading the code, the LED blinks regularly, confirming that the board is working properly.

The code can be written using either Arduino IDE or the dedicated STM32CubeIDE. The main difference between these two is code optimization. Arduino IDE is less optimized but easier to use, whereas STM32CubeIDE is more complex but offers maximum optimization. So, it's up to you to choose what best suits your needs.

Advanced Testing with OLED and Buttons

Next, I built a breadboard circuit with a display OLED and three buttons. The FloppyBoard fits between the two breadboards and connects to the various components through dedicated pins.

• The OLED display is connected via I2C.
• The buttons are programmed with interrupts for fast and precise response.
• The firmware allows incrementing or decrementing a number by pressing the corresponding buttons.

This is a simple example created with STM32CubeIDE that demonstrates the usefulness of external interrupts, which these microcontrollers support in abundance. Almost every pin can generate an interrupt event, which is super useful for many projects!

Button Debounce Management

To avoid incorrect readings due to button bouncing, I added resistors and capacitors to the button circuits. The capacitor helps stabilize the signal by reducing bounce spikes, as seen with an oscilloscope.

In practice, this works like a filter: once the button is pressed (discharging the capacitor), the resistor slows down the capacitor's recharge, eliminating rapid state changes of the button.

1. When connecting the oscilloscope probe to the microcontroller input, you can see that without a capacitor, the signal has spikes.
2. With a capacitor, the signal is clean, eliminating false counts.

Conclusion

This project represents a significant step in developing efficient and cost-effective hardware solutions. For further details and updates on later versions of the FloppyBoard, I invite you to visit my YouTube channel, where you can also find information about the Pet Feeder.

Here you can find the version 3 🤯