The art of hacking requires you to straddle many different types of engineering. In this case, it looks like [Dan] could use a little bit of brain-storming on how to get this doubly-failed project back on track. Do go easy on him as he wasn’t the one that submitted the write-up for this week’s Fail.
He set out to build an automatic baby rocker which he refers to as a baby bouncer. The idea is simple, but execution becomes a bit more difficult to manage. His first attempt is shown on the right. It’s a fairly powerful servo motor, connected to a rocker arm that terminates in a wheel. He used Delrin machined by hand (well, you know what we mean) to fabricate the connecting parts. There’s plenty of torque as this had no problem shearing off the set screw. But the mechanical advantage just isn’t there.
The second iteration is on the left. You can see he got as far as installing it on the rocker, but it’s basically a no-go. The white frame was designed in OpenSCAD and printed by Shapeways. It transitions to a stepper motor with a threaded rod to transfer force to the wheeled-arm. Check out the video below to see how too much resistance causes the mechanism to slip.
There are two things that we think need to be added to this design: mechanical advantage, and jamming relief. Please contribute your constructive comments on how this rocker can be brought up to snuff. This might be a great time to break out your diagram creation skills.
Fail of the Week is a Hackaday column which runs every Wednesday. Help keep the fun rolling by writing about your past failures and sending us a link to the story – or sending in links to fail write ups you find in your Internet travels.