T-wist Release

This post contains all of the STL files you need to put together the T-wist. 

You will also need: 9x M3x8 bolts, some M2 bolts (2x M2x6, 1x M2x8), a single M4 nut and bolt (I use a hex head and a wingnut), a continuous rotation micro servo, a 24mm 10k potentiometer, servo extension leads (I used 6x 30cm leads). Spiral cable binding and cable ties are also a good idea.

(I have not included the T-valve parts in this list)

The drive gear attaches to the servo horn using M2 bolts, though glue would also work. I have used an M2x8 bolt to then secure the drive gear to the servo. Alternatively you could drill through the centre of the dive gear and use the little screw that comes with the servo.

The ring gear sits between the receiver body and base, which are held together using 8x M3x8 bolts. The T-wist receiver attaches to the OSR2 in exactly the same way the standard receiver would.

The potentiometer I recommend you use is a 10k 24mm type, which should be a standard size that's easily obtainable. It is mounted in the top of the T-valve enclosure, through the hole in the top of the new T-valve top. You should hook it up to a servo-type lead; I reckon the best bet is to get a servo extension lead and cut it in half. Make sure that when you attach the leads that the servo "signal" wire (usually white or yellow) goes to the middle pin on the potentiometer. The power and ground (red/orange and black/brown) should go to the edge pins on the potentiometer.

The T-valve should continue to work as normal. Note that there is now manual dial to set the valve position if you don't want to use the T-valve servo.

The drive servo connects to pin 10 on the Romeo. The potentiometer connects to analog pin 0, along with +5v and GND. it plugs in just like a servo would, to a Blue-Red-Black pin combo labelled "0"  in the top left of the Romeo board.

The L-bracket mounts into the receiver using a single M4 nut and bolt. I recommend a hex head bolt and a wing nut. The idea is that if you undo this the L-bracket comes away with the case, making it easy to remove. The potentiometer shaft is secured to the L-bracket via a single M3x8 bolt. I recommend that you tighten this up last, once you have the position centred.

I recommend that when you try powering everything up you are ready to cut the power again if the rotation servo isn't behaving itself. The T-wist should chase the orientation of the potentiometer shaft. If it is moving away from it, you may have to swap the power and ground cables on the potentiometer. Once you are happy that it is centred you can tighten up the M3x8 bolt to hold the shaft in place. If you want to try commanding rotation over serial monitor, use the "R0" channel (ie R0000 to R0999)

I have a couple of ideas to improve this design, so I am expecting to release that next month, along with some more detailed build plans. In the meantime feel free to get in touch with me here or engage with the community on discord if you have any issues or get stuck. I like feedback.

Have fun!