Instructables

Step 6: Placing the velcro onto the armband

For the bands, we cut off shirt sleeves. 
We did not purchase LED armbands because they were expensive in stores and if they were cheap we had to order online.
It's summer so might as well make a sleeveless shirt.
After cutting off the sleeve, but a thin enough strip for the velcro to have about 1/2 and inch of clearance on both sides (top and bottom)
We had couple sets of Velcro lying around. The adhesive on the velcro does not hold onto cloth very well.
So we had to stitch them on. There are many methods of stitching. Go google it. For our method, we just went around in circles.
Mainly stitch down the corners
Make sure both pieces of Velcro are not on the same side of the band. When you loop it around your arm, you'll understand why it won't make any sense.
Put one on the end (doesn't matter which side) and the other on the back side of the opposite side.
When you loop it around your arm, the two pieces of velcro should attach itself so it's a matching pair!
DO THIS FOR BOTH BANDS!