ArduSpinner

A simple dial (aka spinner) input control using arduino and a rotary encoder. The dial is shown in the computer as a mouse with X movement. The movement has been tuned to be "accelerated" so if you do small movements, you have precision, but if you move it kickly, it runs faster. Use a modified version of ClickEncoder library. See below for more details.

Demo video on YouTube

This project provides:

1. The chassis' fabrication models (3D print) and assembly guide.
2. The arduino sketch to control the encoder and pass the mouse inputs to the computer.

Table Of Contents

1. Project Features
2. Part List
3. 3D Printing and Assembly
   1. Parts
      1. Wheel
      2. Chassis
      3. Arduino Holder
      4. Spacers
   2. Assembly
   3. Arcade Installation
4. Electronics
   1. Encoder Mod
   2. Wiring
5. Software
   1. Install
      1. TimerOne
      2. ClickEncoder
      3. ArduSpinner
   2. Tests
   3. Binary
   4. Mame

Project Features

1. Complete implementation for a dial (aka spinner) input control. Just print the files, wire it, download the sketch and play in MAME. The main motivation was to create a low profile, MAME compatible (in fact, it works in all computers that accept a USB mouse as input) input device to play arkanoid style games.
2. Low profile device. Just about 3cm width, 8cm height.
3. Easy to use. Just plug and play with minimum MAME configuration.
4. Easy to build.
5. Cheap.

Part List

To build ArduSpinner you need the following things:

• Arduino Micro or similar, with the ATmega32U4 processor, so we can program the USB interface. Try to build the original one Arduino Micro (18 €) to support Arduino, or, if you're in budget, try this clone from Amazon (4.6 €), but you have to solder.
• Rotary encoder. I use the KY-040 rotary encoder, mounted in a PCB. Get it from Amazon (2,04€)
• Some wiring cable. I use dupont wires (female-female. You need 4 of them), again, a pack from Amazon (6,19€, lots).
• A simple Micro USB cable (DATA, no the stripped version for charge). Just like these Amazon (7,99 €)
• Two small (3mm x 5mm or similar) screws if you want to mount the arduino holder in the back.
• Total: 34,22 € if you buy the "original" kit.
• Total: 6,64 € if you have some dupont cables and the micro USB cable. (just buy the arduino and the rotary encoder)
• Also, you need a 3D Printer, of course, if you plan to print the parts.

3D Printing and assembly

There are 4 parts that you have to print. The STL are ready positioned in the "right" way to be printed, so just print them as is. I use a Ender-3 Pro with Marlin Firwmare, and PLA, and get good results. I use CURA for slicing with the following major configuration settings:

Variable	Value
Layer Height	0.21
Initial Layer Height	0.32
Wall Thickness	0.88
Wall Line count	3
Top/Bottom Thickness	0.92
top Thickness	0.92
Top Layers	5
bottom Thickness	0.92
bottom Layers	5
Top/Bottom pattern	lines
Horizontal expansion	0
Infill density	60>#/td###
Infill pattern	grid
Printing temperature	190
Printing temperature initial layer	195
Build plate temperature	55
Build plate temperature initial layer	75
Initial Layer flow	100
Enable retraction	Checked
Retraction Distance	6.5
Retraction Speed	50
Print Speed	50
Infill Speed	50
Wall speed	25
Top/Bottom speed	25
Travel Speed	150
Initial Layer Print Speed	15
Initial Layer Travel Speed	30
Combing mode	All
Avoid Supports when travelling	checked
Z Hop when retracted	checked
Enable Print cooling	checked
Fan Speed	100
Initial Fan Speed	0
Regular Fan Speed at Height	0.72
Regular Fan Speed at Layer	3
Generate Support	Checked
Support Placement	Everywhere
Support Overhang Angle	47
Support Pattern	ZigZag
Support Density	20
Support Z Distance	0.2
Suport X/Y Distance	0.88
User Towers	unchecked
Build plate adhesion type	None
Surface mode	Normal
Enable Bridge Settings	Checked

This table resumes the printing times for my Ender-3 configuration:

part name	cuantity	color	printing time hh:mm
wheel	1	black	03:35
chassis	1	green	00:31
arduino holder	1	green	00:08
spacers	2	green	00:03

(I print the wheel in black, alone, and the rest of them in green, all together)

Parts

Wheel

• STL
• Thingiverse

Chassis

• STL
• Thingiverse

Arduino Holder

• STL
• Thingiverse

Spacers

• STL
• Thingiverse

Assembly

It's very easy: I recommend you to wire it first:

1. Put the encoder with the connectors as shown in the first photo, and screw the nut tight.
2. Put the spaces between the arduino holder and the back of the encoder, and screw then. Yo get something like a sandwitch (second photo). This allows to create some force between the rod and the back of the encoder.
3. Put the wheel in the rod. Check that the chanfer inside the wheel fits the chanfer in the encoder's rod. Push to the end and you get arduspinner mounted.
4. Press the arduino inside the arduino holder, if you want to mount it there.

Arcade Installation

I design the ArduSpinner to get a low profile, so you can install it in the joystick plate from your arcade machine. I cut a hole of 6.5cmx2.5cm in the table, and screw the ArduSpinner to it. The arcade machine is an own design and it is slim (wood width is about 1cm), but ArduSpinner can be fitted from 1.6cm to 1cm wood boards (or less).

Electronics

Encoder Mod

The KY-040 encoder is a continuous encoder, so you can rotate from left to right continuous. But to "feel" it, the encoder comes with some detents so you get feedback when rotate it. To play, is somewhat crappy, so I remove the detents. This part is just a simple spring that detents the encoder plate. It's easy to remove it.

1. Remove the metallic cover, put in place with 4 pins. Use a plyer and straight them, and remove it (left size of the photo)

1. You find the upper part, the rod with the encoder, and the lower one, the contacts with the button, made in plastic We need to fix the upper part (the rod) so don't mess to much with the lower one (lower part not shown).
2. Remove the plate encoder (just pull) and remove with the plyer the spring (the metallic part in the center of the first photo), then push the plate again into the rod. The should move freely.
3. Assembly the thing. Check for the small metallic plate in the lower part (the button) is in place, put the metallic cover and bend again the pins, and you get a smooth encoder without detents, and a free spring.

Wiring

Encoder PIN	Arduino PIN	Wire Color	Notes
GND	GND	black
+	VCC	red	Works on 5V and 3V
SW	D4	white	Not used, so not connected
DT	D2	grey	Digital Interrupt PIN
CLK	D3	pink	Digital Interrupt PIN

Software

This sketch only works on boards with the ATmega32U4, so the USB interface can be reprogrammed to simulate a USB device (HID) and send inputs to the computer. It's possible to use a software USB stack and use a ESP8266, but it is very complex and only allow a small range of posibilitites. With the new ESP-Pro version, we can reprogram the USB controller as the ATmega32U4. You can use Arduino Leonardo or Micro (I use the last one for size). Pick the original board if you can to support Arduino.

The software is very simple: Just read the data from the rotary encoder, and map it to mouses' X position. There's not so much to be configured, so it should work as is. You can change the PIN assigments, but remember that D2 and D3 are the digital pins that allows interrupts, so if you plan to modify the sketch to use interrupts instead of polling, leave them as is.

IMPORTANT NOTE: On MacOS 10.12.6 I can't get the Leonardo's USB interface with Arduino IDE 1.8.8 working. So please use Windows to burn the Sketch, or use a more updated version of MacOS.

Install

You need the following libraries installed in your Arduino libraries folder.

• TimerOne
• My modified version of ClickEncoder

TimerOne

This library is required in order to work, so you can install it from the Arduino IDE's Library Manager. Just go to Sketch->Include Library->Manage Libraries menu, and search for TimerOne. Add it and that's all.

TimerOne

ClickEncoder

I modify the library to reset the Acceleration when the direction changes, and tuned the acceleration values for my application, so you need to copy it to the Arduino libraries folder (Usually in your Documents folder). Just copy the encoder directory.

ClickEncoder

ArduSpinner

After install and copy the libraries, just restart the Arduino IDE, and open the arduspinner.ino sketch. Now, Just select in the Tools Menu, Boards and check the Leonardo. Select the port, and flash arduspinner.ino on it. That's all. When you move the spinner, the led flashes.

Uncomment //#define RELASE 1 if you want debug output to the Serial Monitor (at 115200 bauds)

Tests

In dev/ folder you could find some tests. They are created to test some functionality. Just for reference.

• test1 Encoder test with interruption handling.
• test2 Polling work with button handling.
• test3 Polling example with debounce. Doesn't work properly.
• test4 MD_REncoder library test. Works. Also includes mouse HID.
• test5 ClickEncoder Library test. Requires also TimerOne library
• test6 My test implementation with interrupts.

Binary

I provide the compiled version for the sketch:

• arduspinner/arduspinner.ino.leonardo.hex
• arduspinner/arduspinner.ino.with_bootloader.leonardo.hex

You can put the file directly in the arduino using for example avrdude or Arduino Builder the process is fairly complex and you can brick the arduino. I recommend you to build and flash using the ide istead, but if you want to try, you're welcome.

MAME

There is a minimum configuration in mame.ini file. Just change keyboard to mouse for dial_device. Save and play. The MAME options for Analog input are set as default (I don't change them). Enjoy!

As a side note, if you run your arcade in windows 7 and you want that Windows doesn't start never in recovery mode, log into windows, and launch a cmd as administrator. then run this: