This is a guide to building simple hopping toy. I've seen mechanically-driven versions of this, and like those, this one entertains a 4-year old for a good period of time.
Step 1: Hopping Our Way
Hoppers are simple mechanical toys. The weight spins around and moves the bot about by balancing badly. These things skitter around delightfully when you flip the switch and they're fairly safe for pets and young children.
- a frame (1/32" sheet metal)
- legs (marking flag wire)
- battery pack (from Radio Shack)
- switch (also from Radio Shack)
- red and black wire (20-24 gauge, though in a pinch, CAT-5 cable will work, but double it up))
- 2 small wire ties (long enough to wrap around your motor)
- off-center weight (2" of thin-walled, 1" electrical conduit)
Tools you'll need:
- Permanent marker
- Hack saw/rotary cutter/tin snip (and a file, depending on your cutting skills)
- Pliers (fairly heavy, you'll need to bend the wire)
- wire cutters/stripper
- soldering iron
- hot-glue gun
I got interested in these when looking at BEAM mechanics. I've got another set of these that will use a simple photovore head to control two counter-rotating weights to follow a light source. However, this tutorial shows the basics of building the form.
You'll start with small L-shaped piece of sheet metal. I find that the guts of flat-bed scanners have all kinds of good stuff in them. The legs are made from a single piece of wire, and I use the 18" wire marking flags for can get from Lowes or Home Depot. Switches and motors came from Radio Shack .
The template below is the frame of the bot. The Sketchup files are included, as well.
Print out the template and mark it on your sheet-metal, or just mark it out. Cut along the solid lines, and make sure you end up with the same number of fingers as you started with.