Ready to deploy design #2

February 16, 2023 · View on GitHub

Read this document from start to end before building anything. Ensure you understand everything.

This setup has not been tested at the system level. If you try, please, let me know.

Hardware features

Bluetooth Low Energy
Powered through USB (or, optionally, external power source)
Button box (64 inputs):
- Up to 52 general purpose push buttons.
- Up to 4 relative rotary encoders (with push button).

Item	Quantity	Notes
bare bone Rotary encoder	up to 4
Standard perfboard sized 24x18 holes	1
Push buttons	up to 52	General purpose (up to you)
Pin header (male or female up to you)	136	For external wiring
Schottky diodes	56	1N4148 recommended
Resistor (any impedance 4K to 100K-ohms)	4
ESP32-WROOM-32UE/E (DevKit-C)	1	Male pins already soldered. Choose built-in/external antenna.
External Antenna with U.FL, MHF I or AMC connector	1	Only required if ESP32-WROOM-32UE is chosen
Micro-USB cable long enough	1	For power

Other parts (quantity unknown):

Thin cable.
Cable with Dupond terminals (for external wiring). Some cable kits for protoboards will do the job. ¿Male or female? the opposite to pin headers.
Welding tin.

GPIO	Input	Output	Usage	Notes
36	OK		Matrix input 1	input only (no internal pull resistor)
39	OK		Matrix input 2	input only (no internal pull resistor)
34	OK		Matrix input 3	input only (no internal pull resistor)
35	OK		Matrix input 4	input only (no internal pull resistor)
32	OK	OK	Matrix input 5
33	OK	OK	Matrix input 6
25	OK	OK	Matrix input 7
26	OK	OK	Matrix input 8
27	OK	OK	ROTARY1_A
14	OK	OK	ROTARY1_B	outputs PWM signal at boot
12	OK	OK	ROTARY2_A	boot fail if pulled high
13	OK	OK	ROTARY2_B
9	x	x	UNUSABLE	connected to the integrated SPI flash
10	x	x	UNUSABLE	connected to the integrated SPI flash
11	x	x	UNUSABLE	connected to the integrated SPI flash
6	x	x	UNUSABLE	connected to the integrated SPI flash
7	x	x	UNUSABLE	connected to the integrated SPI flash
8	x	x	UNUSABLE	connected to the integrated SPI flash
15	OK	OK	Matrix selector 1	outputs PWM signal at boot
2	OK	OK	Matrix selector 2	connected to on-board LED
0	pulled up?	OK	Matrix selector 3	outputs PWM signal at boot
4	OK	OK	Matrix selector 4
16	OK	OK	Matrix selector 5
17	OK	OK	Matrix selector 6
5	OK	OK	Matrix selector 7	outputs PWM signal at boot
18	OK	OK	ROTARY3_A
19	OK	OK	ROTARY3_B
21	OK	OK	UNUSED
3	pulled up	RX pin	UNUSED	HIGH at boot
1	TX pin	OK	UNUSED	debug output at boot
22	OK	OK	ROTARY4_A
23	OK	OK	ROTARY4_B

Setup #2 circuit layout

This layout includes the following subsystems (read for an in-depth explanation):

Notes and build tips:

Some components may look very small, not matching their actual size. This is not a mistake. They must be placed in vertical position, so they lie in a minimal surface of the perfboard. All resistors and diodes should fit in 1x4 holes when they lay in horizontal position.
There is a lot of wiring, which is prone to human error. Check wiring and traces twice before soldering.
Choose one and only one power source (USB, EXTERNAL_5V0 or EXTERNAL_3V3). Your board could get damaged if using two power sources at the same time. EXTERNAL_GND must be used along with EXTERNAL_5V0 or EXTERNAL_3V3 (but not both).

Rotary's built in push buttons are wired to the button matrix (terminals SW and SW GND) as any other push button.
Each input has an assigned number in the circuit layout. Certain inputs have a particular function, so attach them properly.

At Arduino IDE, configure the board manager for "ESP32 Dev Module".