It has the same Lego gear and axle assembly as the previous vectoring thrusters, although I changed the gear ratio to 2:1. I used Lego rods at the motor mount beams, extending out 50% more than the toy blimp to get better turning leverage.
But the really cool thing is that I added RC control to the Blimpduino's autonomous control. That way I can fly the blimp manually to test different motor and vectoring strategies and otherwise understand the blimp's aerodynamics.
The way it works is that under RC control, I connect the RC receiver's channel 1 (steer right/left) to the ultrasonic sensor port, and the channel two (steer up/down) directly to the vectoring servo. I'm writing some Arduino code to read the channel 1 PWM on the ultrasonic port pin and convert that into signals to the Blimpduino's two motor driver chips. Basically that ultrasonic sensor port now has dual functions, depending on which program I'm running.
When I want to fly autonomously, I just take off the RC receiver and have Blimpduino control both the vectoring servo and the motors itself, connecting the ultrasonic sensor back to its regular port.
The Li-Po battery (the red thing underneath the receiver at the back of the board) powers Blimpduino and also the RC receiver, via the channel 1 port.
Other parts needed:
- Two N20 motors
- Two props
- Blimpduino board
- A 52" envelope
- Either a small 7.4v Li-Po battery, or a 4xAAA battery holder
Here's a close up from the side:
Comments
At the kind of volumes we're talking about here (hundreds, maybe a few thousand max), I think I can get what I need no prob. If that doesn't seem too cheesy, I just need to get their permission to "resell" the parts in the kit. Again, I think they'll be okay with it, as part of a good cause (and a non-profit effort).
Sorry about the crappy photos above. Once I write the code and test it on the blimp (next weekend) I'll take some proper shots and videos to show how it works.
The point is to bring the cost of this kit to about $50 wholesale. Parts:
--Envelope
--Assembled BlimpDuino board
--Plywood strip
--Two N20 motors and props
--One nano servo
--Some Lego pieces (is it too cheesy to actually use Lego? They work great!)
--One 4xAAA battery holder
The BlimpDuino board is set up to accommodate expansion daughterboards, such as a compass sensor or bluetooth wireless. It can also drive two more motors, if you want to add tail/nose thrusters for better control.
http://www.balloonkits.com/