RCM-Hardware-V4

v1.3

• 4 motors and 7 servos OR 6 motors and 3 servos
• 3 additional input only pins
• 2 x 3 inches, 50.8 x 76.2 mm
• runs from 5 NiMH AA batteries OR 4.5-12v with the addition of voltage regulators (see list of components)
• Qwiic connectors OR two more GPIO pins
• all components are hand-solderable through-hole parts except for the Qwiic connectors which are surface mount

Compatible with 38 pin devkitC ESP32 boards

program with RCMv2

Alternatives

• An upgrade from the original 3 versions of RCM boards

• Here are smaller and more powerful RCM boards: BYTE and Nibble

Options for purchasing

• PCBWay link (PCBWay will give me a commission without increasing the price for you). (approximately $5 for 5 boards and manufacturing takes 1-7 days).
• send the gerbers to a PCB manufacturer of your choice (details you may be asked for: min hole: 0.3mm, min track/spacing 6/6mil, 1 oz Cu outer)

Components

Solder by hand to assemble your boards.

part	links	quantity	notes
RCM V4 circuit board	see options for purchasing above	1
ESP32 devkitC 38 pin	digikey or find on Amazon	1
L293D (or SN754410)	digikey	2 or 3
16 pin IC socket		0 to 3	depending on whether you solder the ICs directly and how many motors you want to use
30k resistor		1
10k resistor		1
47uF capacitor		1
Qwiic connector (JST SH)	digikey	0 to 2
4 male header pins		1	for I2C pins
5 male header pins		1	for extra input pins
7 male header pins		4	for servos
4 female header pins		3	for motors (can also use one 12 pin strip instead)
19 female header pins		2	for esp32
battery wires	2 male header pins OR JST RCY OR 9V battery snap	1	Amazon JST RCY
servo buck boost 5v 2A	Pololu	0 or 1	if you want to supply voltages above or below what servos can accept (supplies other than 5AAs)
esp32 buck 5v 0.6A	Pololu	0 or 1	if you want to supply voltages above 7 volts (supplies other than 5AAs)

The six pins at the bottom of the board near the QWIIC connectors are not connected to anything. They are meant to be used for soldering practice before adding components that matter.

Acknowledgements

• I would like to thank PCBWay for sponsoring prototyping runs of this project. PCBWay produces very nice boards, supports open source hardware, and gave me great support as I worked on this project. Special thanks to Liam!