I never made my own, but I saw a posting on a ice fishing specific site (www.icefishingchat.com), where someone made there own, you can see the stuff he used and how they go together to get an idea for it:
http://www.icefishingchat.com/viewtopic.php?t=4135&highlight=
The ones I have look just like that, but I got mine from my Dad, they seem pretty receptive to bites. I had good luck with them last season.