This project is my wearable call sign badge. Its a PCB with my name and call sign, with a small micro-controller that will send my call sign as Morse on an LED.
The badge remains powered constantly, but the micro-controller is in a low power state drawing a very tiny current (somewhere in the region of 10-20uA) so the CR2032 cell will last a long time in standby.
When initially powered up, or when the reset button is pressed, the micro-controller will send out the programmed Morse Code message at about 10 words per minute. It will repeat the message, with a small delay between, five times, then go back to sleep.
The hardware schematic and PCB are designed in Diptrace, there is a free version available.
The design centres around a PIC10LF322, an 8-bit micro-controller from Microchip. I use the 6 pin variant in an SOT-23-6 package. This is powered by a CR2032 cell in a holder and has a minimum of additional components to flash the LED.
There is a reset switch (to restart the sending sequence once it goes to sleep) and a programming port on the back to allow the firmware to be updated.
I've also added a small prototyping section with all signals accessible for hacking on additional circuits if desired.
On the back of the PCB is a series of pads that match the standard PicKit3 programming cable ordering. I have a set of pogo-pins soldered to 0.1" vero board that seat on the pads for programming.
There is a slot for a badge clip, and a pad on the back where a small brass tube could be soldered for a safety pin to clip the badge to your shirt.
This is a simple Makefile based assembly language project. I've implemented
it on Linux using the Microchip XC8 MPASM assembler.
The Makefile will need to be updated to point to the correct installation
locations for XC8 and MPLABX. (I used the MPLABX installation to drive my
PicKit3 for programming only, so it can be skipped).
The firmware will send a Morse code message (for instance a call sign) repeatedly several time, then it will go back to sleep until the reset button is pressed.
While sending the Morse code, the micro-controller will be asleep as much as possible as well.
Ashley Roll. VK4ASH. 2020-04-11