My local children museum has something like this. Let me see if I can find a picture to give you an idea of the set up. It does look like it would be $$$ for set up. What’s your price point?
Cool! I’m still looking for a picture. I’ll post when I find it but thinking about this more I know there are a ton of toys like this made. Most are for older kids and are priced at about $20-80.
Look up circuit station kids science and you should get an idea of the kits.
Yeah around three they should be able to do it with adult supervision but it’s still a bit of a toss up on if they are going to put the small parts in their mouth. I can’t find the a good photo of the big one at my local children museum. It’s going to drive me crazy. I’ll probably just have to take a picture next time I go in.