Ready to deploy design #3

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 rechargeable batteries
• Built-in battery monitor
• Analog clutch paddles (potentiometers).
• Shift paddles (x2)
• "ALT" buttons (x2)
• Relative rotary encoders (with push button): x2
• Up to 10 additional push buttons

Button mapping

• Bite point calibration: rotary #1 clockwise and counter-clockwise (while holding one and only one clutch paddle).
• Next clutch function: START and Left shift paddle.
• ALT buttons mode: START and Right shift paddle.
• Recalibrate clutch paddles: Left shift paddle, Right shift paddle and START.
• Power on: rotary #1 clockwise or counter-clockwise.

Needed parts

Item	Quantity	Notes
Bare bone rotary encoder	2
Roller lever	2	For shift paddles (maybe they are included with your wheel's case)
Linear potentiometer 10 K-ohms or higher	2	For clutch paddles (maybe they are included with your wheel's case)
Push buttons	up to 10	General purpose inputs (up to you)
Schottky diodes	16	1N4148 recommended
Standard perfboard sized 24x10 holes	1
Unexpected Maker's TinyPico Devkit board	1	With male pins already soldered
Pin header (female)	20	For a DevKit board with male pins already soldered
Pin header (male or female up to you)	28	For external wiring
LiPo Battery 4.2V (max)	1	Must fit TinyPico's specification. Capacity and size up to you
Both male and female GX16 (5 pins) connectors	1 male and 1 female	For the charging port
Micro-USB/USB-C spiral cable long enough	1	For charging. Must match your TinyPico USB connector.
External Antenna with U.FL connector	1	Only required if TinyPico V3 with U.FL is chosen
On-board battery connector	1	Depends on your battery

Other parts (quantity unknown):

• Thin wire.
• Wire with Dupond terminals (for external wiring). A kit for protoboards will do the job. ¿Male or female? the opposite to pin headers.
• Welding tin.

Other notes:

• The GX16 connector may be replaced by any other kind. The GX16 features a knot that prevents accidental unplug. The 5 pins flavor allows to build a fully capable USB port, not just a charging port, if you want.

Pin-out plan for the TinyPico DevKit board

GPIO	Input	Output	Usage	Notes
25	OK	OK	Left pot
26	OK	OK	Right pot
27	OK	OK	ROT1_A
15	OK	OK	ROT1_B	outputs PWM signal at boot
14	OK	OK	ROT2_A	outputs PWM signal at boot
4	OK	OK	ROT2_B
23	OK	OK	Matrix input 1
19	OK	OK	Matrix input 2
18	OK	OK	Matrix input 3
5	OK	OK	Matrix input 4	outputs PWM signal at boot
22	OK	OK	Matrix selector 1
21	OK	OK	Matrix selector 2
32	OK	OK	Matrix selector 3
33	OK	OK	Matrix selector 4

Circuit layout

Open the circuit layout using DIY Layout Creator.

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

• Power through a powerboost module already built in the DevKit board.
• Battery monitor through a built in voltage divider.
• Switches.
• Relative rotary encoder bare bone type.
• Analog clutch paddles.

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.
• There is a lot of wiring, which is prone to human error. Check wiring and traces twice before soldering.

External wiring

• Each input has an assigned number in the circuit layout. Certain inputs have a particular function, so attach them properly.
• The POTn_GND and POTn_VCC terminals of each potentiometer are interchangeable. If the clutch (or axis) goes to 100% when idle, swap those terminals. If you don't have the chance to swap those terminals, the companion app has the ability to swap axis polarity by user request.
• Note that the pin headers on the left and right clutch paddles are symmetrical, not identical.
• Battery(+) is the positive pole of the battery.
• Battery(-) is the negative pole of the battery.
• Attach Battery(+) and Battery(-) properly. Take care not to swap those terminals.
• Bare bone rotary encoders: their built-in push button must be wired to the button matrix just like any other push button, being SW and SW GND the involved terminals.
• Battery charge port:
  • Cut the USB cable near the Micro-USB/USB-C end, but leave enough length to reach the GX16 plug.
  • Make sure matching GX16 pins in both male and female connectors are soldered to the same wire (same color).
  • Red and black wires are mandatory. Others are optional.

Firmware upload

At Arduino IDE, configure the board manager for "TinyPICO".

You should calibrate your battery first. See the Battery calibration procedure.

1. Plug the USB cable to the Devkit board and upload the sketch with Arduino IDE.
2. Open the serial monitor (Arduino IDE).
3. Reset.
4. Check there are no error messages.