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.

Electric Long-board

When this year’s lock-down started a few months ago, I finally bought myself a long-board so that I could keep up with the kids on their bikes or scooters when exercising.
It didn’t take long before I remembered that I always wanted to build an electric "toy" that could carry myself.
I contemplated a bike, a Go Kart and others, but it’s always been pretty obvious that the easiest to attempt would be a skateboard…

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:

Self balancing robot

It’s really been a very long time since I added this on my todo list, and in the past couple of week-ends I finally found the time to do it.

Stepper motor bluetooth serial driver

First Test using an Arduino (clone) board

Above is the image of my very first attempt of driving this nice little bi-polar stepper motor (M35SP-11HPK) that I had salvaged from a broken Canon printer a while ago.

I have quickly put together a L293D H-bridge with an Arduino board and using the Stepper library was quite straight forward

For the impatient you can see a (probably boring) video right after the break…

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…

Motor vibrations

No motors running, just "natural" noise of the sensors...

This post is obviously related to my “roman-fleuve” post about my attempt at building a quadcopter… I’ve decided however to create a new post as the initial one has already become too long, and dealing with vibrations is a more general mechanical question, that applies to much more than just quadcopters.

I still don’t know why my quadcopter refuses to balance properly, and to be honest it could be anything: the frame, the motors, the ESCs, the code, literally ANYTHING !

However, I have the feeling it’s related to vibrations, and there’s only one way to find out: done with the funny part of building the quad, now enters the tedious/annoying task of setting a vibrations test bench and do some measurements…