Touch Plate v2
- 1 Step by step instructions for making a good touch plate
- 1.1 1. Create the contact material
- 1.2 2. Create the touch plate holder
- 1.3 3. Drill the mounting hole for the jack
- 1.4 4. Mount the audio jack in the enclosure
- 1.5 5. Solder the jumper wire to the audio jack
- 1.6 6. Mount the enclosure
- 1.7 7. Prepare the audio cable
- 1.8 8. Drill side hole in the touch plate holder
- 1.9 9. Solder the contact material
- 1.10 10. Solder the alligator clip
Step by step instructions for making a good touch plate
Making a good touch plate is fairly simple, as long as you can do basic soldering. :)
The instructions below will guide you to making a good one.
A touch plate is made up of a cable piece which has the actual touch plate on it, along with a jack section connecting the cable to the Shapeoko electronics.
- The cable piece consists of the touch plate holder, touch plate contact material, an alligator clip, and a modified audio cable.
- The jack section consists of an audio jack mounted in the controller enclosure, and the jumper wire connecting this jack to the two probe pins on the Shapeoko controller.
The touch plate holder and the contact material look like this:
1. Create the contact material
For the contact material, use something conductive but reasonably soft so end mills aren't damaged when contacting it. Mine is a piece of copper plate, as seen in the top photo.
[TODO - Add URL to the copper plate I bought through Amazon]
The contact piece is 19mm in diameter, to fit neatly in it's holder (the aluminium piece also in the photo). I used this STL for cutting it from a larger piece of copper plate:
2. Create the touch plate holder
For the touch plate holder, I used 5mm aluminium from Amazon.
[TODO - Add URL to the 5mm Aluminium I bought through Amazon]
Use this STL to CNC it:
The rest of the materials you'll need are:
- Touch plate contact point (copper plate)
- Touch plate holder (5mm aluminium)
- An alligator clip
- 3.5mm audio cable
- 3.5mm audio jack
- 2-wire jumper wire - PTH
- Heat shrink to cover the soldered components
- Some super glue (or other basic adhesive). Only a very small amount needed.
[TODO - Add URLs to the exact components I used]
That photo is missing the 3.5mm TRS audio jack by mistake. :(
3. Drill the mounting hole for the jack
You need to create an 8mm hole in the Shapeoko enclosure for mounting the audio jack in. This can be anywhere you want, as long as it gives adequate clearance to the other pieces:
I used an 8mm drill, but any method for creating it will do.
4. Mount the audio jack in the enclosure
The audio jack comes with a simple screw on piece attached to the back of it. Take that off, mount it in the hole, then put it back on. The end result should look like this:
5. Solder the jumper wire to the audio jack
The next step is to solder the jumper wire to the audio jack.
Use the two short contact points - one for each of the jumper wires - and leave the long contact point unused. It doesn't matter which way around you solder the wires to the short points, as the jumper wire on the other end can plug in either way around. When you're done soldering, it should look something like this:
It's a good idea to cover the exposed metal surfaces with heat shrink too:
6. Mount the enclosure
Now mount the enclosure, sliding the jumper onto the two "probe" pins on the controller board.
The probe pins are the 3rd and 4th ones from the right most side, as shown in the top photo here:
It should look like this:
7. Prepare the audio cable
Next, cut the 2 RCA connectors off from the audio cable. DO NOT cut off the 3.5mm audio plug, as that needs to keep on the cable. ;)
After cutting off the 2 RCA connectors, strip the cable a little ways like the photo below:
8. Drill side hole in the touch plate holder
The touch plate holder needs a small hole drilled in it from the side, for one of the audio cables to fit through. I used a 2mm end mill to create the hole. After it's drilled, one of the stripped audio cable wires goes through the hole like the photo below:
[TODO - Add URL to the 2mm end mill I bought through Amazon]
9. Solder the contact material
Solder the touch place contact material to the wire that you feed through the hole in the previous step. Ensure the connection is done well, then super glue the contact material in the holder and allow to dry.
10. Solder the alligator clip
Lastly, solder the alligator clip to the other stipped audio cable. The result should look like this:
And it's complete. Now go and try it out using bCNC or similar. :)