New BlimpDuino test platform (now with RC!)

After I added vectoring thrusters to the toy RC blimp, I realized that I needed a better test platform to find the best combination of motors, control loops and mechanical elements to give the blimp maximum control. I also realized that we hardly needed any of the toy blimp parts anymore. So I built a blimp controller/power platform from scratch, using the usual Lego pieces and thin plywood.

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:

Here's a close up from the side:

Views: 2448

Comment by Howard Gordon on June 2, 2008 at 7:43am
Looks good, Chris. Next step is to replace the envelope. You might look into building your own via the materials offered here -
http://www.balloonkits.com/

3D Robotics
Comment by Chris Anderson on June 2, 2008 at 9:22am
I'm going to see if I can get a bulk discount on the 52" envelopes from RCToys. (The standard envelopes for the Mach 3 are not 52" as described, but closer to 49". At any rate they can't carry as much...) If I can get the price down to $15 each, it's worth it....

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.
Comment by Howard Gordon on June 2, 2008 at 9:50am
Only issue with Lego parts is that they are only available as part of Lego kits. However, you may be able to source the parts in some volume here - http://www.bricklink.com/

3D Robotics
Comment by Chris Anderson on June 2, 2008 at 12:46pm
I have friends in high places in Billund ;-)

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).

3D Robotics
Comment by Chris Anderson on June 19, 2008 at 9:59pm
Here's the code for the above platform. Right now I'm running it on a dev board, rather than the Blimpuino board, but the next version of the Blimpduino board will run it natively.
Comment by Nick Wagner on September 3, 2008 at 6:57pm
The links you have for the props are broken... I was just wondering what model you were looking at using for the test platform, or better yet the final product.

3D Robotics
Comment by Chris Anderson on September 3, 2008 at 7:28pm
Thanks for the catch. Prop link now fixed. The final product will be similar to this gondola (thin ply board with Lego Technics shafts and gears), but with a MUCH better PCB. We're probably still a few weeks from releasing the board files and a few months away from selling the final kit.
Comment by ovidio aza rojas on November 14, 2009 at 7:28pm
cuanto hidrogeno nesecita para levantar 1000 gramos 1kl. y ese modelo cuanto hidrogeno lleva para poder volar

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