I recently got the Twiddler3, a one-handed chorded keyboard. It's held in one hand and secured in place with a soft felt strap. The problem with the strap is that it wouldn't stay in place with the hook-and-loop ("Velcro") attachment. The felt surface wouldn't/didn't survive more than a few readjustments, and never felt all that secure.
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Step 1: Gather Supplies
- Twiddler3 - the reason you're here
- Elastic strap - I used 1 inch width, but use whatever's comfortable
- Fabric glue
- Old credit card (or other flat piece of plastic/metal)
- Toothpick (or other thin rod approx 1.5 mm diameter)
- Vice grip (or other locking clamp) -- will need 2 of these, or get creative with clamping.
Step 2: Prepare Strap and Card
Cut the card into small strips (see photo).
Cut a length of the elastic about 1.5x the width of your hand, or about 20 cm (7-8 in). This will be "too long", so experiment with this.
Apply fabric glue to both ends of the strap. On one side try to put the glue near the very end.
Step 3: Seal the Ends
Take the side with the glue near the end and wrap the toothpick so that the glue doesn't stick directly on the toothpick.
Place two of the plastic strips on either side of the glued portion of the strap, right next to the toothpick.
As the glue starts to dry, twirl the toothpick a few times to keep it from bonding with the elastic strap.
Fold the other side over and clamp it with the plastic strips also. (See note at the end.)
(The pictures are in reverse order; I fused the "other" side before the toothpick side.)
Step 4: Finalize the Strap
Once the fabric glue is reasonably dry, remove the clamps.
Slide the toothpick out and set aside.
Trim the (pick) pocket side to about 1.25 cm.
Also cut the toothpick to 1.25 cm long.
Slide the toothpick fragment back into the pocket.
Step 5: Attach Strap
Slide the anchor end into the slot on the Twiddler. I don't think it makes a big difference, but I prefer to orient the trap so that the fold is on the inside. It looks cleaner that way and probably slightly more secure.
Next, attach the strap end to the Velcro. The best way to do this is to put the elastic on stretch and press it onto the Velcro. This opens up the fibers and allows for a more secure fit.
Step 6: Finished!
- It might be a good idea to seal the cut surface of the strap with heat/fire to prevent fraying.
- Instead of gluing the free (non-anchor) end of the strap, you could just cut it and seal with heat. I used glue because I didn't have a heat source.
- There ends up being a lot of shear force on the Velcro attachment, causing the Velcro to slip slightly. I have a feeling that it will come off eventually but that's a project for another day.
Let me know if you try this, or if you come up with a better strategy!