An electronic badge for ScotCon members and visitors. Low cost, straightforward self-assembly, unicorn or pusheenicorn shape, LCD, neopixels, multimeter, IO ports
Max 100x100m 2 layer 1.6mm FR4 material, 1oz copper, 0.3mm min hole, 0.4mm solder mask dam, 0.42mm min track, HASL finish, blue finish/white silkscreen for minimum manufacturing cost from Seeed Studio
Form factor: Unicorn, Pusheenicorn or Saltire, must be easy to mill, no complex shapes/sharp corners to minimise cost
ARM Cortex M4 STM32F303K8 Nucleo board (64K Flash), development environment ARM MDK V5 (free version, 32K code limit), OpenSTM 32 also possible, no code size limit but less stable
Nokia 5110 LCD, 500uA @3V 6mA @5V (can reduce backlight LED current via resistor) Neopixels on tail/mane Buttons and/or joystick/rotary encoder
0-50V DC/AC, continuity, diode test
UART/serial port - serial terminal or packet radio monitor connected to TNC? Shitty Add-On (I2C) connector Wireless - NRF42L01 module (cheap clones on eBay) - interact with other badges; 433 MHz packet radio receiver - pager receiver or LED control?
3V battery: LiPo, 2xAA or coil cell? Or 1x AA and boost converter? USB charging?