Print PDF
Favorite
Email
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.
Remove these ads by
Signing UpStep 1Description 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.
| « Previous Step | Download PDFView All Steps | Next Step » |
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.
We have found that the IMU (Gyroscope/Accelerometer) here in the instructable is no longer available, so we have ordered the new 6DOF digital version.
It will take some time to change the code over.
If you feel game enough to do it your self then let us know if you get the code worked out and I can post it here,
I'm happy to answer questions if you need specifics on brands used or want to know if a certain motor will be powerful enough.
As for wire, buttons, dc connectors, dill pins use ebay, google or your local electronics store.
These are standard components and easy enough to find yourself.
The joystick we use are Happ brand.
Button version
http://www.ebay.com/itm/1-HAPP-COMPETITION-8-WAY-JOYSTICK-ARCADE-JAMMA-MAME-tm-/380381260883?pt=LH_DefaultDomain_0&hash=item58907d6c53
Analog version
http://www.ebay.com/itm/HAPP-ANALOG-JOYSTICK-GRIP-TRIGGER-AND-THUMB-BUTTON-NEW-NR-/380416080843?pt=LH_DefaultDomain_0&hash=item589290bbcb
The one we used was about $300 I think.
i did contact the seller of the
http://www.ebay.com/itm/HAPP-ANALOG-JOYSTICK-GRIP-TRIGGER-AND-THUMB-BUTTON-NEW-NR-/380416080843?pt=LH_DefaultDomain_0&hash=item589290bbcb
and i sent to him the diagram shown in this page he reply me that the joystick in this page is different from the one he offer it !!
could you put me in the correct joystick match the one on the diagram
Ask them about adding the buttons.
At the begging thank you ..
i got imu analog 6 dof sensor do i can use this connection or i have to buy the 5 dof sensor? if the 6 dof sensor ok...do i need make any change in the code...? i hope NO.......here is the connection
http://voidbot.net/razor-6dof.html
It looks like the 6 dof razor has the same accelerometer chip but has 2 seperate chips for the Gyroscope.
So yes you will have to change the code that measures the angle.
We have ordered the Digital SEN-10121 IMU from Sparkfun to change over to digital.
They seem to be going away from the analog units.
Rod
If anyone wants to try to get the Sparkfun 6dof DIGITAL IMU working in a self-balancer I have cobbled together some code and attached it to page 53 of my self-balancing skateboard instructable.
IMU reading code is based on the work of someone else and my button-controlled skateboard code has been taked on around it. Not tested in a real machine yet but all the values it spits out into the serial view window on attached laptop seem about correct so, apart from a few inevitable bugs, I think it should self-balance.
All wiring etc described in comments at start of the sketch.
I have also done something similar with a 6dof ANALOG "Razor" IMU (still available if you shop online around the globe) and attached sample code to one of the other steps in my instructable. Accel data scaling is unchanged from the 5dof one but gyro scaling needed a few code adjustments. This IMU is also being phased out however so getting the digital one to work is the only long term solution for this emerging community of self-balancer builders.
•Shielded multi core cable for the accelometer and heavy power cable for the motors
•Deadman switch
•Toggle switch for turning. A joystick is good for this.
•Toggle switch for adjusting balance poisition.
•DC connector for Arduino.
•DIL pins to suit Arduino
put us on ebay link for examble?
so are you going to change over to digital ...all the diagram and the code soon...?
The motors are 250W geared motors. It probabaly does about 10km/h but we are going to gear it up some more for higher speed.
There is no limiting as yet but the up and coming new code will have some.
At the moment it runs out of puff and the nose drops and skids on the ground.
It works great up inclines/declines, across grass etc.
Very stable and fun!
Rod
Im kinda new to electronics, but would the Sabertooth run 2x 500w 24v motors?
Cheers
Power (watts) divided by Voltage = Current
500 / 24 = ~21Amps
So the sabertooth 2x25 is 25Amps normal and 50amps peak for a few seconds.
It should be ok!
Personally I would go up to the 2x60 Sabertooth to make sure it will handle surges.
Rod
- 2x 250watt/24v motors
- 1x 3Ah 24v Battery or 3Ah 24v Battery (Wasnt Sure)
And provided I do the correct math.
For the 12v Battery
250w / 12v = ~20.83 Amps
3Ah / 20.83A = 0.14Hours
0.14 % of an hour is 8.4 Minutes Drive time.
and for the 24v Battery
250w / 24v = ~10.41 Amps
3Ah / 10.41A = 0.28 Hours
0.28 % of an Hour is 16.8 Minutes Drive Time
Is this correct? if so then I can calculate how much battery I need to achieve my desired drive time.
what toggle switch we can use ...is in ebay can be found the joystick ?
i was just wondering though would adding a car battery and skid wheels instead of pad throw the balance off ? because id love to have a better run time than 30 minutes and knowing myself (which im glad i do) i will definately try ti get it further back than it will go
Gidday mate!
Weight doesn't seem to affect it, but you should try and keep the weight centred if possible.
But there it a tilt adjustment for fine tuning.
And can't use the name Segway!
The visit to your Scitech workshop was so excellent and thank you for fine- tuning my segway, I have changed the handle bar to a more ridged one and now it works real good. I call it 'The Nutty Professor' in honour of your scitech show in Harvey.
The user was able to remain "motionless" on two of its four wheels. It was interesting to watch the Ibot's movements while attempting to remain motionless. It was continually correcting for movement of the user (shifts in mass centroid) by moving slightly forwards and backwards. It never seemed to rest.
We bought my wife one and it is great!
It was designed as a bit of fun to show the balancing mechanism.
You can build one an use bigger wheel. The balancing mechanism will handle that but for safety we stayed low and added skid pads(not seen in the first photos. Will add today).
Also racing wheel chairs aren't that high either.
Having said that, though, I tend to be extremely conservative. I hate the Segway model of trusting your safety to a dynamically compensating computer, rather than to a passively stable equilibrium.
Of note it is the ability to be upright and look people in the eye or even over them that the Segway was designed for. Like Wragie said the chair is low. You are looking at Butts. And the chair is wide. But the chair is very cool. and with the skids I wouldn't worry about having a single fail point at all.
I think I am going to make one. Especially since I have nearely 200 Segway batteries, each with 92 18650 lithium cells in them. Even the bad batteries have many good individual cells.
Great project guys!
Personally I do keep an eye out on these projects for idea that would make mobility type chairs better. I had to use one just enough to know what a total pain they are. One instructable that still stands out to me and the guy really truly deserves some kudos is a fellow in Morocco who was scrounging the junks yards for scrap steel, batteries, and old office chairs to make them. He was building these for next to nothing. Even replicating his build with everything off the shelf was under $500 here. That impressed me enough I spent 6 months trying to talk the so called charity/service organizations into looking into it. Seems they would rather spend $2K on a standard chair instead of spending the same on something that would actually make a difference to someone.
"Not everyone you see in a chair is 70 years or older" -- Um, not at all. The guys who play murderball can't be over thirty, or I think they'd all be dead :-)
Your comment about local (U.S.) organizations preferring to pay for a commercial chair than to build their own has a lot to do with (a) the medical/insurance model, and (b) liability. If you build a chair from scratch, and give/sell it to someone else, then you are liable if it fails, or worse, if it fails in such a way as to cause injury. Consequently, you are much better off buying a commercial device, for which the manufacturer has assumed that liability.