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A pocket-sized debugger for monitoring serial data.

Sometimes you need to quickly check the state of the device and having to use a computer for that can be a bit bothersome. A pocket-sized debugger that can monitor and display the data stream is the perfect solution for that!

So how does it work?

On the upper right corner, there’s a pin header (RX, TX, GND) meant to be connected to the device you want to receive data from. The current iteration is only 5V tolerant, in the future we plan to add a switch to shift between the 5V and 3.3V logic levels.

We’ve used an ILI93441 2.2” TFT display and an ATmega328P microcontroller (the design is based on the Arduino Nano schematic) for reading and displaying the serial data. We’ve also added a rotary encoder with push button, which can be used to switch between different baud rates, scroll through the text or pause/resume autoscrolling.

We’ve ordered the PCBs from JLCPCB in matte back and, as it sometimes happens with first prototypes, some things needed to be fixed :”) The display we’ve used is only 3.3V tolerant and most tutorials recommended adding 1k resistors in series with the data pins when used with a 5V microcontroller. That didn’t work though, so we’ve had to add more resistors to complete the voltage divider. But there’s nothing that some patience and copper wire can’t fix! (Putting to use all the skills from circuit sculpting :P).”

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