Imported from GitHub: dbking77/robojoy_pcb · commit d066fc5 · license MIT

Description

Robot Joystick

README

RoboJoy PCB

Wireless (BLE/Wifi) joystick with small screen. Can be powered by 4x AA (1.5V Alkaline or 1.2V NiMH) batteries.

Parts List

Description	Qty	Cost	Supplier	Supplier Part Num	Manuf	Manuf Part Num	Note
DevBoard+Screen	1	20.00	Amazon	?	Waveshare	ESP32-C6-LCD-1.47
Joystick	2	0.71	Digikey	1188-JOYSTICK10K-CAP-ND	Olimex	JOYSTICK 10K-CAP
Joystick Alt	2	5.24	Digikey	1568-09032-ND	SparkFun	09032	expensive similar footprint
Battery Holder	2	1.03	Digikey	36-2462-ND	Keystone	2462
Slide Switch	2	0.36	Digikey	2223-SLW-864574-5A-RA-N-D-ND	Same Sky	SLW-864574-5A-RA-N-D
Schottky Diode	2	0.15	Digikey	B140Q-13-FDICT-ND	Diodes Inc	B140Q-13-F	Buy Qty 10
Diode 0.8Vf	1	0.04	Digikey	5399-S1MCT-ND	Silkormicro	S1M	Buy Qty 10
Resistor 10k 0603	5	0.09	Digikey	311-10.0KHRCT-ND	Yageo	RC0603FR-0710KL	Buy Qty 10 or 100
Capacitor 10000pF 0603	5	0.09	Digikey	399-C0603C103K5RACTUCT-ND	Kemet	C0603C103K5RACTU	Buy Qty 10 or 100. Optional
Female Header 9pos	2	0.63	Digikey	S7042-ND	Sullins	PPPC091LFBN-RC	Optional, can solder devboad header directly to PCB
Male Header 40p Break	1	0.43	Digikey	S1012EC-40-ND	Sullins	PREC040SAAN-RC	Optional, sometimes comes with DevBoard. 40pos breakaway only need 1 for two 9pos

Filter Capacitors

Used to optinally low-pass filter analog joystick and battery voltage signals, may not be needed.

Pull-up Reistors

Internal GPIO weak pull-up resistors are probably enough to reduce need for external 10k pull ups

Female Header

Optional, allows Wireshare DevBoard to be added/removed. SDCard slot is on bottom of dev board, and is inaccessable

Battery Protection Diode (D1)

Diode prevents USB current to trying to "charge" the AA batteries, when plugged in. However, since the USB port is part of the dev-board there is no way to prevent battery power from flow (backwards) to host computer. USB-C computer ports my have protection for this, but results might vary. It is good idea to switch off battery power when connecting device to USB.

D1 could be replaced with a jumper wire.

AVCC and AGND Diodes

This adjust voltages provided to joystick potentiometers. These are needed for analog joystick to work.

Notes

• LCD 172x320
• Onboard regulator is 800mA max

Battery

Alkaline is about 1.5V new, but around 1.2V for most of operation. NiMH is about 1.3V when new about 1.2V for most operation.

Battery Voltage Measurement

Voltage divider will double 2.5V ADC to 5V.
3v3 regulator will stop operating about 3.4V.

With 4x batteries, assume anything above 1.2V/cell is 100% Assume 0.9V/cell is 0% (0.9 * 4 = 3.6V)

3v3 Linear Reg

The waveshare uses a ME6217C33M5G linear regulator

• 100mV dropout @ 300mA
• Max 6.5V range