Manual Grinder/Food processor
The Wondermill Junior Deluxe claims that it will grind chickpeas, it's over $200 American. I've found several articles (example) that claim you can do it in a manual coffee grinder. Here's a reasonably priced, highly rated manual coffee grinder from Amazon. Amazon will let customers ask questions of others that have purchased a specific item. I asked if that particular grinder will grind raw chickpeas. I'll update this post if I get a credible answer.

EDIT: I did get an answer from somebody on Amazon who owns that particular coffee grinder. She tried it (just for you:) It didn't work. The beans were too hard for the machine.

Other articles recommend a meat grinder.

You mention a windmill though. Are you wanting to do huge amounts?

Another point of clarification: Are you grinding dry or soaked chickpeas? If you want to grind dry chickpeas, the coffee grinder is almost certainly the better option (although maybe not since this one didn't work at all). For soaked chickpeas, you'd probably be better off with the meat grinder. Since I've seen recipes for falafels starting either way, I can't know which way you are wanting to do it.