Building the PacoMouseCYD DCC Throttle

The universal wireless throttle PacoMouseCYD is a very interesting design. It is a universal wireless throttle based on low-cost electronic modules made for Arduino projects. This means it can be built with minimal electronics skills.

I decided to use a slightly more professional approach and added two optional features. At the same time, I describe a method of assembly so the throttle fits well into a case and looks like a well-crafted product, even though it uses ready-made modules.

This is only a build guide. It assumes the user has already read the user and construction manuals (for example: [https://github.com/fmcopaco/PacoMouseCYD/tree/main/doc](https://github.com/fmcopaco/PacoMouseCYD/tree/main/doc)).

I will try to include links to specific components. However, these are from Chinese marketplaces, so the links may not work for a long time. Also, price and quality may vary. The same components can be bought from local suppliers, usually with guaranteed quality.

Purchased components:

1. Cheap Yellow Display ESP32-2432S028R Aliexpress
2. Rotary encoder module EC11 with knob Aliexpress
3. Switch SS12D00 (I used 6 mm, but 4 mm is enough) Aliexpress
4. Battery charge/discharge module TP4056 with protection Aliexpress
5. Lithium battery 103450 (2000 mAh, 3.7 V, 50×34×10 mm) Aliexpress

Other materials:

1. Very thin solid wire, cross-section about 0.02 mm² (32 AWG)
2. Flat ribbon cable (flexible), pitch 1.27 mm, 28 AWG (0.08 mm²)
3. 3D printed case

Note about wires:

If you do not have very thin wire, you can use the one included with the display. It is stranded wire, which is harder to work with, but still usable. You can also use or enamel wire.

The flat ribbon cable is the same type used in older computers, for example for floppy drives or parallel hard drives. I used a colored version because it is easier to track connections.

It is better to modify each module first and connect them later. I modified the display module for battery monitoring and the encoder for better function and quicker response.

ESP32-2432S028R Display Module

This module was probably not designed for battery use. Therefore, the Vbat input of the XPT2046 chip is not connected.

You need to connect the positive power supply to the Vbat input (pin 7 of the XPT2046). No other changes are needed.

The XPT2046 is in a TSSOP16 package with 0.65 mm pin spacing. Make sure you are able to solder such small pins.

I used very thin wire with Teflon insulation. It does not melt during soldering. You can also use stranded wire or enamel wire. The maximum cross-section must not exceed 0.03 mm² (32 AWG).

Cut a 5 cm wire. Strip and tin both ends. First solder it to pin 7 of the XPT2046, then to a power point. I used point JP3 (the one closer to the edge). You can also use test point S3.

This step requires high precision.

EC11 Encoder Module

The version I received has capacitors C1 and C2 with 150 nF. This is too high. A better value is 10 nF to 15 nF.

I removed these capacitors and replaced them (in the photo they are removed). Some versions may already have correct values.

Resistors R1 and R4 are between the encoder output and the processor input. They have a value of 10 kΩ. This is too high and causes incorrect operation.

Since we use the processor power supply, these resistors can be shorted. I bridged them with solder and a small wire.

The last modification is removing the pin header. Pins are not practical and increase box height. I removed the black plastic first, then desoldered each pin one by one. This is the easiest method.

Encoder to display

Using connectors is not practical and increases the size of the case. The connectors also support only very thin wires. Therefore, I used direct soldering.

To connect the encoder and display, you need a 5-wire cable, 13 cm long. I preferred easier soldering over color matching. On the display side, I soldered the wires in the same order as in the cable.

I soldered the wires directly to the back of the connector. The pin spacing matches the cable (1.27 mm), which makes soldering easier.

On the encoder side, the spacing is larger. It is easier to solder wires according to the schematic. Be careful to avoid mistakes.

In my case, the encoder direction was reversed. I had to swap outputs S1 and S2. This is easy to do on the encoder side.

Power Connection

You need a 2-wire cable, total length 11 cm. At 5 cm, cut the positive wire and connect a switch.

After soldering the switch, connect the cable to the back of the display module connector. The distance between display and switch is 5 cm.

On the other end, solder the TP4056 charging module. No modification of TP4056 is needed. Just connect to OUT+ and OUT- correctly.

Finally, connect the battery to the TP4056 module. The battery already has wires, so no modification is needed.

If you have not uploaded the program to the ESP32 yet, now is your last chance. After installation in the case, the USB-C connector is not accessible, and the micro USB is very hard to reach.

From version 0.11, the software supports updates via SD card. So connector access is not necessary.

Pavel created a very precise case based on a design by Isaac Guadix. In this version, the display is mounted with the antenna at the top. This improves WiFi range but blocks access to connectors.

Carefully place all parts into the printed case. After that, the controller is ready to use.