Electric Longboard – v2

Quick update on my Electric Longboard.

It works surprisingly well, and even the fact that the 150W motor feels rather under-powered when I try to use it (it does work but I feel like it could go faster and it does take a bit before it reaches top speed) could be considered a “feature” as it’s plenty of power for when the kids play with it in the park 🙂

One issue that we kept having was the 3D printed plastic motor mount would break when hitting small holes or irregularities in the asphalt.

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Autonomous Army Truck – 1. Mechanics

This is the 6 wheels drive toy army truck that I bought several years ago (for fairly cheap) for one of my kids.

When reading the specs (6wd, 3 differentials, independent suspensions on each wheel, etc. … ) it sounded too good to be true for the price… and indeed, I remember being disappointed when I received it : the rubber of the wheels kept coming off, the battery was really bad, but most importantly both the steering and the main motor were simply on/off not *proportional* !

At the same time, I was impressed by the modularity of the design, how everything was screwed rather then glued in place and how easy everything was to take apart, ready to be modified / upgraded…

And I *knew* I could do better… sooo much better !

Here’s what it can do *now*, after the 2 main mechanical upgrades:

Simple Radio Controlled Car

There’s nothing much to say about this, no micro-controller or programming or any fancy stuff involved… it’s just that I’ve always wanted to build a simple RC car for my kids…

Arduino, when the Servo library is not good enough…

 

I went back to try and finish this ball balancing project, but after some improvements I started to get frustrated by the fact that the servos kept being “jittery”.

Time for my new and shiny servo tester I thought… ! It turned out I was seeing the same problem.

Android – IOIO – RC Servo (or ESC)

This is a sequel to my first Hello World example with the IOIO / Android setup….

Android + IOIO controlling a RC servo

Tiger 1 BB airsoft RC Tank – V3

This is the sequel of 2 other posts describing previous work on this project:

• version 2 of the tank attempt
• and the initial work which dealt more with the low level building.

It also builds on this previous post, which is all about interfacing the WiiMote IR Camera with the NXT and tracking an IR LED with a Lego motor.

11Jun2011 – FINALLY !!!

Everything seems to work nicely together now it not only tracks and locks on the target, but it finally shoots PLASTIC PELLETS !

Tiger 1 BB airsoft RC Tank – V2

It’s all about the same project as here, BUT with a different technology: instead of using the FEZ Domino (.NET micro framework based) board, I’ll be using the Lego NXT controller and an Arduino board for low level interaction with the electronics.

NXT + Arduino internals

Tiger 1 BB airsoft RC Tank

CONTINUED HERE…

Together with a work colleague we have set ourselves a challenge: buy 2 1/16th RC tanks capable of firing BB pellets and transform them such that we can have an AUTONOMOUS BATTLE !

Unboxing

Graupner R700 FM receiver – get the PPM signal

This must have already been discussed on plenty of other forums, but here I am, I want to use my Graupner FM transmitter / receiver with my quadcopter.

As Jordi from DIY Drones says “Intercept the PPM signal is the best way to obtain all the channels from any receiver, for a lot of reasons. The first one is performance, and the second is the simplicity (in code =P).”

First of all, here’s a quite useful diagram that explains well how the PPM works, and the relationship between this signal and the individual channels:

RC Receiver Timing Diagram

The Graupner/JR R700 FM receiver is quite easy to hack.

Quadcopter – home made

29 Mar 2011 – V2 is here !

Latest and greatest version, not that light but not too heavy either...

Quadcopter V2

Now I know it was all useless, but until 2 days ago, I still thought the only problem with my quad was the frame/motors and the huge vibrations they generated…

2 days ago, on Sunday night, I finally had the courage to face the truth : it could be my fault, it could be my code ! 🙂

Actually while looking at the http://www.multiwii.com/ site (huge thanks Alexandre, and really great stuff !!!) it occurred to me that their code should support my configuration out of the box.

To be honest, I’ve always though that it might be a problem with my code, but the only options to check this would have been:

1. buy an ardupilot or some other verified system and install it
2. modify the ardupilot or some other verified code to make it run on my configuration

None of the above options were easy and they could have introduced new problems by themselves…

But the multiwii code, looked like it should work with barely a few lines of change !!!

And indeed it WORKS ! Or at least it balances muuuuch more steadily on 1 axis !

This seems to prove that while I do have quite a lot of vibrations they don’t stop the quad from flying.

I still don’t know what the exact problem was with my code, I will have a look into the details once I manage to fly for real with the new code…