LARS V2

This is the second iteration of the hardware. The principle is the same as for the prototype, with the same chinese modules used. Only the buttons have been changed, and there are now 9 of them, with 8 LEDs. The battery is now mounted on the board. It is planned to be used without a case.

You can download the Gerber files to order PCBs online.

assembled V2 PCB

Revision 1 was using the SMD-only footprint for the Raspberry Pi Pico. Revision 2 has changed this to be compatible to THT as well.

Warning: Revision 1 and 2 are missing diodes on the button matrix. So when holding down three or more buttons simultaneously you get ghosting on other buttons.

Bill of Materials

These are all the parts required to assemble the V2 PCB.

IDTypeLink
U1Raspberry Pi PicoReichelt.de, Amazon.de
U2TP4056 Charger ModuleAmazon.de
U3 - U5MOSFET Module N-ChannelAmazon.de
U6 - U8Step-Up Converter ModuleAmazon.de
OLED1SSD1306 128x64 0.96" DisplayAmazon.de
BT1Keystone 1042Reichelt.de
S1APEM 5236ABReichelt.de
SW1ALPS EC12E24244Reichelt.de
-Cap for encoder knobReichelt.de
SW2 - SW10DIP 6x6mm push buttonReichelt.de
D1 - D41N5819 Schottky DiodeReichelt.de
D5 - D12LED 5mmReichelt.de
R1Resistor 10k Ohm 0.1% AxialReichelt.de
R2Resistor 18k Ohm 0.1% AxialReichelt.de
R3 - R10Resistor 1k OhmReichelt.de