[Stephan Jones] has an easy method for making your own model rocket engine igniter. The solid state motors used in this hobby consume one igniter with each electrically triggered launch. Whether you’re making your own motors or not, this construction technique should prohibit you from every buying an igniter again. The process involves bending some nichrome wire around a paper clip, adding some structural support to the leads using masking tape, and insulating the business end with a quick dip in paint.
Now would be a good time to send us your launchpad hacks. All we’ve seen so far is a launchpad for water rockets.
[KoD] and [Navic] are building solid propellant motors using sugar and potassium nitrate. They cook up the two ingredients along with water and a bonding agent. They find that corn syrup is particularly good for bonding and that cooking the strange brew is more of an artform than science. Either way, the video after the break is proof of the dangers involved in this hobby. Testing the engine thrust with a bathroom scale ends badly for the scale.
There is something satisfying about the ingenuity that goes into the materials. For a casing they’re using PVC pipe, and forming a cone to focus the thrust by using a what amounts to plumber’s epoxy putty. The capping agent for the finished motor is ground up kitty litter.
This is an interesting read, but for now we’re going to stick to water rockets.
Continue reading “Homemade solid propellant rocket motors”
While hobby brush motors are pretty cheap now adays, there’s always that feeling of why replace when you can rebuild and reuse. As such [John Carr] presents how to change the brush position in motors to revive a dead motor. So long as the motor dies from natural causes commutator wear, the idea is the brushes can be moved along the axes and fixed to a new portion of commutator that’s not worn at all. [John] also goes through the details of some tricky reassembly, but we think to make this complete a guide on brush replacement and commutator replacement might be in order hint hint.
This scooter has been fitted with a three-phase induction motor. It reminds us of the sound effects from vehicles in the Jetsons. Right now they’re using lead-acid batteries and get about 15 miles of range from one charge. Once they switch over to lithium polymer they calculate the range will be closer to 45 miles due to the reduced weight and increased capacity. Not bad for $600 in parts, and we’d bet it’s both faster and more stable than the one-wheeled-wonder we saw last week.
[Craig Carmichael] has been hard at work on his electric hub motor for cars. Unlike typical electrical vehicles the plan is to bypass the transmission, differential, and everything else all together by connecting directly to the hub of the wheel. The goal of giving greater thrust and still allowing the use of a gas engine if need be.
There’s really too much detail for us to even begin to try to explain the entire project in a short recap, but [Craig] builds the entire motor (from magnets to coil windings) and wires his own controller (from schematic to finished PCB), all while documenting the process thoroughly for those wishing to make their own.
Motorized treads as a replacement for the heel of your shoe? Okay, remember how The Jetsons had moving sidewalks everywhere so you wouldn’t have to walk at all? Well, there’s a much more efficient way to do it and Treadway Mobility seems to have figured it out. In the video after the break you can see several of their prototype units zipping the wearer around quite happily. We think the best part is that with the tread locked in place you can stand and walk like normal, assuming you don’t feel like you have a block of concrete attached to each foot. Maybe the real question is which is more geeky, this or the power lace shoes?
Continue reading “Heel treads make shoes go”
A table and chair that can move around by themselves? What’s next, suicide booths, self-replicating robots, and Star Trek styled tablet computers? It seems that [Adam Lassy] is moving in that direction. He took this furniture from Ikea and made some neat modifications to give it mobility. Each of the four legs has wheels on them and the legs themselves rotate in unison to change the direction of travel. We could see the table as a more practical drink delivery system than the Bar2d2. It certainly would make for some great late-night pranks but the chair motors need to be silenced before that can happen.
[Thanks Balbor via Ikea Hacker]