One day whilst at work we decided we would build something cool so we went to the Instructables website for ideas! Our criteria was that it had to be driven by an Arduino! After searching through the vast amounts of really cool projects, we found XenonJohn's Balancing Electric Skateboard
We thought we should build a stand-on Balancing scooter but then decided that we needed to make something original. What about a Balancing chair my boss said. Now that's cool!
We happened to have a cool looking Carbon Fibre Racing chair just sitting around not being used so we started with that. We previously ordered a couple of geared down 250W scooter motors and some wheels to suit.
Now to order the electronics! Reinventing the wheel is a waste of time, and XenonJohn had already developed the code and worked out which hardware to use so we ordered exactly what he recommended.
Power came from some Makita drill batteries. These are used for most of our travelling exhibits as they are easy to get, to charge and we have a few batteries laying around for just such a purpose.
Here is a short video of the chair being driven around. Note the 3rd build Balancing scooter too doing a drive through.
We thought we should build a stand-on Balancing scooter but then decided that we needed to make something original. What about a Balancing chair my boss said. Now that's cool!
We happened to have a cool looking Carbon Fibre Racing chair just sitting around not being used so we started with that. We previously ordered a couple of geared down 250W scooter motors and some wheels to suit.
Now to order the electronics! Reinventing the wheel is a waste of time, and XenonJohn had already developed the code and worked out which hardware to use so we ordered exactly what he recommended.
Power came from some Makita drill batteries. These are used for most of our travelling exhibits as they are easy to get, to charge and we have a few batteries laying around for just such a purpose.
Here is a short video of the chair being driven around. Note the 3rd build Balancing scooter too doing a drive through.
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Signing UpStep 1: Description of the Build
The description of this build a little bit in reverse as we built the chair fairly quickly and forgot to take build photos.
There is little or no detail about the balancing software or how it works as XenonJohn has already described this so well.
There will be details on how we built our SciChair and what you will need to do to build your own.
The electronics is nearly exactly what XenonJohn used on his skateboard but I have removed the resistors he used for the switches so therefore, the code is different. See attached code for button steer and proportional steer.
There is little or no detail about the balancing software or how it works as XenonJohn has already described this so well.
There will be details on how we built our SciChair and what you will need to do to build your own.
The electronics is nearly exactly what XenonJohn used on his skateboard but I have removed the resistors he used for the switches so therefore, the code is different. See attached code for button steer and proportional steer.
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Thanks for your patients waiting for the code.
Well it's finally here!
Both the switch steer and the resistor pot steer.
Wiring is quite easy. I have a simple diagram to show what goes where.
Enjoy and let me know if there is anything missing or questions.
Well my boys and I are embarking on a build based on your SciChair...we have purchased all the items including the 5 DOF accelometer (linked to in the parts list) and can't seem to work out how to wire this in to the circuit based on the different board layout. Can you provide some guidance on this...
We live in Adelaide and hope to have our self-balancing "cockpit" up and running in a few months...we would also love to send some photos and perhaps video when we finally get things sorted.
Thank you for all the info in your instructable, it seems pretty straight forward and gave us the confidence to embark on our journey :)
But in the mean while if you look at the old sparkfun IMU and connect the same names as the new IMU.
The buttons on the joystick should connect to the tilt adjust mechanism.
I'll check it!
Can wait to see a video.
This value is in the annotation as 350 but the value I used in the code is 340.
Change it up/down by about 5 and this will change the tip start position.
The only issue is that bumps move your hand and the joystick more.
We used a joystick that doesn't give full left or full right for the movement.
It's a 100k we are using but that doesn't matter as you put 5volts across the terminals and read the voltage from the wiper.
If you disconnect the gnd and 5volt lines and fit a 2k resistor inline between the gnd side and the 5volt side.
This means the reading will never reach 0volt or 5volts.
That should fix your issue.
http://www.ebay.com/itm/181004141876?ssPageName=STRK:MEWNX:IT&_trksid=p3984.m1439.l2649
We will be writting code for the 6DOF digital version soon.
John has written code for that IMU which it sound like you have.
http://www.instructables.com/id/Easy-build-self-balancing-skateboardrobotsegway-/step53/Code-for-use-with-new-6dof-DIGITAL-IMU-from-Sparkf/
Test it out and let us know how it goes.
what the value of potentiometer is used in the steering??
John who wrote the code we are using has done some code to use the IMU you have.
http://www.instructables.com/id/Easy-build-self-balancing-skateboardrobotsegway-/step53/Code-for-use-with-new-6dof-DIGITAL-IMU-from-Sparkf/
Let us know how it works.
It looks almost like a wheelchair for a disabled person, except for the smallish wheels.
Can it go up a curb from street to sidewalk?
Nope won't go up curbs unless it's ramped.
He wrote the code.
http://www.instructables.com/id/Easy-build-self-balancing-skateboardrobotsegway-/
With your code chair would like to build a scooter type V2 but with the steering right and left driven by two potentiometers at the base of the steering column.
You can do?
What should I change in the code?
What pots to use?
Sorry for the many questions ..
Thank you very much,
Sincerely, Gerry
You only need one potentiometer for the steering.
Have the other one as a small one that you set to the middle position.
Tilting the unit will still work as normal.
Or remove that part out of the code like the scooter has.
As for a potentiometer get a good quality one for RS components or someone.
The gyro should be mounted with the 2 holes in it at the bottom and the chip side facing towards the back and vertical.
When starting the unit the gyro should have a tilt on it.
So first tilt the gyro, turn on power and DO NOT MOVE IT for 5 seconds.
This is very hard if being held in your hand. I suggest sticking it to the bottom of a ruler so that large movement at the top equals small movement at the bottom.
Now turn on the deadman switch. Tilt the gyro upto the vertical position and the motors should kick in.
Tilt the ruler around the vertical position and the motors should reverse and slow.
Tilt it more and it will speed up.
We don't bother doing dry runs as we know the circuit/code works.
The only issue you should have is the motors being connected the wrong way and sitting it up on some crates allows you to tilt start.
Hope this helps.
I have attached the lastest code we have.
It is propotional steer and driving forward/back via the joystick.
It also has a feature with a flashing status for the gyro for turn on.
Basically you turn on power and the light will flash until the gyro has locked on (about 4 seconds) and then goes steady.
Thanks alot guys never would have conceived of building this without this instructable!!!
Ron
Your most welcome. You just made my day!
Cheers
Rodney
Still using the sabbertooth?
Man it gets going.
Just a disclaimer!
Wear a helmet! The code isn't perfect so don't rely on it, especially at high speed.
And there is no governer/speed limiter in the code so when you get to top speed the motors can't keep up and the front will touch the ground.
Be safe and have fun!
But awesome job!
Ron
you managed to create the new code with potentiometer for joystick forward / backward?
IMU What are you using?
Can I get a code from your code for 3-wheel scooter without IMU?
Sorry for so many questions.,
Regards, Gerry.
Use the wizard for the sabertooth in analog mixed mode steering.
http://www.dimensionengineering.com/datasheets/SabertoothDIPWizard/start.htm
Rod
There is no CAD model for the chair.
The frame dimentions would vary due to the size wheels you use, the type and size chair you use. The size person you want to fit in the chair.
Take the basic frame design you see and design yours to suit the chair, wheels, person you are going to use.