Instructables
Picture of SciChair (Balancing Electric Chair)
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.

















 
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Step 1: Description of the Build

Picture of 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.

ScitechWA (author) 2 years ago
Hi Everybody.
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.
Caterg1 month ago

Hello guys, if someone has the 5DOF module dual-axis accelerometer + gyro instrument, and have interested in selling to Brazil, I'll pay whatever it takes. Need this component for ongoing project. Thank you for your attention. Several websites that looked not send to Brazil or is missing. cat@caterg.com.br

hi guys.

i build the scichair but when i go to program the arduino it says that 'the keyword BYTE IS no longer supported'

how do i fix this ?

it is in the code line

SaberSerial.print(0, BYTE); //kill motors when first switched on

}

ScitechWA (author)  jake.penney.71 month ago
Download the earlier version of arduino program Version 0023

You are faced with the same problem as me.

A few posts below, I also asked about it, the reason is the version, this code only works with version 0023.

if you want ispolzovat recent version 1.0 and above you will have to spend a recoding, I now work with version 1.5

here everything is clear described https://decibel.ni.com/content/thread/11196?tstart=0

Maksvl1 month ago

Good afternoon. Collected on your grand project, there are several issues.

Why and when the authorization gyroscope impossible immediately command the movement or rotation of a joystick. Joystick it starts listening only after a small inclination.

And why the team to retain the balance comes slightly inert (in my opinion), although it is perhaps because I put on a very experiments and a small prototype. And hold the balance or does not work. I tried already to increase value to 1 (float aa = 0.005; // this means 0.5% of the accelerometer reading is fed into angle of tilt calculation with every loop of program (to correct the gyro)) but rvno balance is not maintained.

Thanks in advance for your answers.

ScitechWA (author)  Maksvl1 month ago
Hi,
Thankyou for your comments.
All code is an "as is" basis.
We copied the code from another project. "Balancing skate board."
So we did not write the code. We did some changes.

The code works for us fine.

Check your gear ratio. Too high will not allow you to balance.
Maksvl4 months ago

Produces here such errors

C:\arduino-1.0.2\libraries\SoftwareSerial\SoftwareSerial.cpp: In member function 'void SoftwareSerial::begin(long int)':

C:\arduino-1.0.2\libraries\SoftwareSerial\SoftwareSerial.cpp:396: error: 'PCICR' was not declared in this scope

C:\arduino-1.0.2\libraries\SoftwareSerial\SoftwareSerial.cpp:399: error: 'PCMSK2' was not declared in this scope

C:\arduino-1.0.2\libraries\SoftwareSerial\SoftwareSerial.cpp:399: error: 'PCMSK0' was not declared in this scope

C:\arduino-1.0.2\libraries\SoftwareSerial\SoftwareSerial.cpp:399: error: 'PCMSK1' was not declared in this scope

C:\arduino-1.0.2\libraries\SoftwareSerial\SoftwareSerial.cpp: In member function 'void SoftwareSerial::end()':

C:\arduino-1.0.2\libraries\SoftwareSerial\SoftwareSerial.cpp:414: error: 'PCMSK2' was not declared in this scope

C:\arduino-1.0.2\libraries\SoftwareSerial\SoftwareSerial.cpp:414: error: 'PCMSK0' was not declared in this scope

C:\arduino-1.0.2\libraries\SoftwareSerial\SoftwareSerial.cpp:414: error: 'PCMSK1' was not declared in this scope

ScitechWA (author)  Maksvl4 months ago

Use version arduino-0023.
That will fix those errors.

Maksvl ScitechWA4 months ago

Sorry for my English is not clear.

Thank you very much, I tried running without errors.

What do you think the account conversion here this way?

https://decibel.ni.com/content/thread/11196?tstart...

ScitechWA (author)  Maksvl4 months ago

Yes if you convert those codes it should work.

Just as easy to download the old version.

Maksvl4 months ago

Which version of the Arduino sketch written? When compiling an error.

This one will be right for a gyro? http://www.ebay.com/itm/5DOF-module-accelerometer-and-dual-axis-gyro-instrument-IDG650-ADXL335-/261488421936?pt=LH_DefaultDomain_0&hash=item3ce1ecac30

austiny68 months ago

Hi. I am building my own SitWay and I think your components and codes are great.

The IMU link you provided is a blue accelerometer that is way more expensive than the red one you have in the image which is around 15US. Should I order the red one? In addition, I have a Triple Axis Accelerometer & Gyro Breakout SEN-11028

do you think I can use your code directly for that?

I am a high school student and am very eager to finish this project in time. Thank you

ScitechWA (author)  austiny66 months ago

This IMU will not work with the code.
It's a digital IMU and the code is for an analog one.

heath_kerr10 months ago
Making life easy,ha
_Rommel_1 year ago
Hello, how much RPM for my motors is recommend?
The specification is specified as 320 revolutions per minute
Maksvl1 year ago
The documentation pdf file is not correctly specified the polarity of the battery.
You wrote about the blue LED that blinks for about 4 sec gyro calibration. But I did not find it on a map.
Maksvl1 year ago
I apologize for the error - I write through a translator.
Maybe someone else is looking for an analog gyroscope.
Here's the link itself today already ordered a 2 piece
http://www.aliexpress.com/item/5DOF-axis-analog-gyro-sensors-module-IDG500-IDG655-IDG650-ADXL335-module/578668074.html
ScitechWA (author)  Maksvl1 year ago
nice find
Maksvl Maksvl1 year ago
Why then the link does not want to be inserted
aliexpress.com/item/5DOF-axis-analog-gyro-sensors-module-IDG500-IDG655-IDG650-ADXL335-module/578668074.html
_Rommel_1 year ago
Yesterday i ordered all parts for my self-balancing scooter project, but the code i think to get from here and the joystick function as well. Sometimes when i dont want to tilt forward/back ill use the joystick.
ScitechWA (author)  _Rommel_1 year ago
Yes the code can be used by leaning forward/backwards or using the joystick.
fredbana1 year ago
thank you sir for quick respond
fredbana1 year ago
are you useing 5k pot? for steering?
ScitechWA (author)  fredbana1 year ago
5k or 10k It's used as a voltage divider.
Hi ScitechWA,
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 :)
ScitechWA (author)  TheVenueManager1 year ago
I'll have to draw up a new diagram for the new IMU.
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.
Also as a follow up question...I have had a look at the code and there does not seem to be anything addressing the forward and backward buttons of the joystick???
fozz181 year ago
is the code set to go slower than the segway-clone code you used?
ScitechWA (author)  fozz181 year ago
no it should be the same. Is thee an issue?
fozz181 year ago
how do I change the balance point? the annotations are not clear to me
ScitechWA (author)  fozz181 year ago
Do a search through the code for the value 350.
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.
fozz181 year ago
(removed by author or community request)
ScitechWA (author)  fozz181 year ago
Yep that's great. Works the same as the one we used but smaller.
The only issue is that bumps move your hand and the joystick more.
fozz181 year ago
got everything working tonight without changing your code. it was a loose wire causing my problem. What value potentiometer do you recommend the steering is super sensitive. I'm using 10k ones.
ScitechWA (author)  fozz181 year ago
That's awesome. I'll put the link up for that IMU.
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.
fozz181 year ago
sorry to bother you but I have 5DOF module that I got from eBay and cant seem to get it working with your code any help would be appreciated I'm at a stand still here
http://www.ebay.com/itm/181004141876?ssPageName=STRK:MEWNX:IT&_trksid=p3984.m1439.l2649
ScitechWA (author)  fozz181 year ago
That's right that one won't work as it uses a different chip to the one we used.
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.
greetings sir,
what the value of potentiometer is used in the steering??
fozz181 year ago
(removed by author or community request)
ScitechWA (author)  fozz181 year ago
That's right the analog versions were nice and easy to read.
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.
bgoldberg11 year ago
Very cool looking! :)

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?
ScitechWA (author)  bgoldberg11 year ago
lol. Except they don't use Carbon Fibre racing chairs. lol.
Nope won't go up curbs unless it's ramped.
bcamaro1 year ago
Please explain Why TORQUE = 9
ScitechWA (author)  bcamaro1 year ago
You might want to ask John that question.
He wrote the code.
http://www.instructables.com/id/Easy-build-self-balancing-skateboardrobotsegway-/
Hello,
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
ScitechWA (author)  gerrymazzotta1 year ago
Hi,
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.
bcamaro1 year ago
What is TORQUE.
ScitechWA (author)  bcamaro1 year ago
In physics, a torque is a vector that measures the tendency of a force to rotate an object about some axis.
kaizoku301 year ago
hi, i am building a self balance scooter using the pot steer code using 2 350w 2750 rpm motors, 2 12v 7.2ah sla battery. This thing happened to me when i doing a circuit dry run. when i tilt the gyro, it does not have any response, but when it does, it run full speed clockwise, tilting back to the opposite direction does not change the direction . One thing i notice is when the motor start running, the error led on the sabertooth blink one time and goes off. Any idea what i have done wrong? Thanks.
ScitechWA (author)  kaizoku301 year ago
Hi, Just checking your startup proceedure and gyro position.
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.
Could you verify that the Scichair_pullup_pot_24_feb_2012.txt file is the pot steer code? I had a good look at it and it still looks like it's the toggle switch version. Thanks for uploading this instructable, I'm hoping my version will be up and running this weekend.
ScitechWA (author)  TheWreckingYard2 years ago
Lol. Sorry about that.
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.
Excellent, thanks alot!
ScitechWA (author)  TheWreckingYard2 years ago
LOL. Wow. That's brilliant. We wanted to build a big one.
Your most welcome. You just made my day!

Cheers
Rodney
ScitechWA (author)  ScitechWA2 years ago
What Motors and batteries are you using?
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!
Thanks, I bumped up a bit on a few things but electrically it's pretty much the same thing. I used a Sabertooth 2x60 controller, 600W 2400rpm motors (no gear reduction, which might be iffy), same gyro/accelerometer and then I just swapped in the PS2 controller library. As well I used a pair of 12V 20Ah batteries, switched on with a large 24V solenoid. No idea what the run time is but it`s alot of fun. Disclaimer taken, I already clipped a power pole with it. :)

Ron
Thanks again for posting this, I just got mine working today, I made a few changes in that I used a Playstation 2 controller for driving it, works great! I uploaded a driving video to YouTube at: http://youtu.be/s_AOMc45DnY

Thanks alot guys never would have conceived of building this without this instructable!!!

Ron
Hello,
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.
ScitechWA (author)  gerrymazzotta2 years ago
A 3 wheeled scooter doesn't need to balance so you don't need an IMU or an arduino.
Use the wizard for the sabertooth in analog mixed mode steering.
http://www.dimensionengineering.com/datasheets/SabertoothDIPWizard/start.htm

Rod
Can you please upload the CAD model of the Scichair???
ScitechWA (author)  pranav vempati2 years ago
Hi,
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.
ScitechWA (author) 2 years ago
Replace IMU link updated in Parts list. Thanks 3ug3n.
Can you please post the dimensions of the the frame???
ScitechWA (author) 2 years ago
Ok I'll answer some of the questions here.

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.
hi ,

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
ScitechWA (author)  monjidj2 years ago
http://na.suzohapp.com/joysticks/95070100.htm

Ask them about adding the buttons.
monjidj2 years ago
hi there ,
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
ScitechWA (author)  monjidj2 years ago
Hi Monjidj,
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
Hi,
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.
also could you put us on link to buy the exact joystick
•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?
its ok if i useing arduino mega 2560 ? will not effect ?

so are you going to change over to digital ...all the diagram and the code soon...?
Awsome 'ible i've been looking at XenonJohns builds for a while and have been considering making a skateboard but this may have to come first, I was wondering what kind of speed or power you can get out of it, like does it have the power to go up inclines and maintain a safe speed on declines? Also I have looked at the arduino code before and is there a speed limiting parameter or is it just zero to full power with the 255 setting? Thanks for the great 'ible.
ScitechWA (author)  scottrevoman3333 years ago
Hi,
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
Hi,
Im kinda new to electronics, but would the Sabertooth run 2x 500w 24v motors?

Cheers
ScitechWA (author)  ben.is.broad2 years ago
A quick electronics lesson.
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
So based on what you have
- 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.
johnmac20112 years ago
hi,
what toggle switch we can use ...is in ebay can be found the joystick ?
hey bro its great to find the second project on my list is from a fellow aussie ! its an incredible idea honestly really great
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
ScitechWA (author)  curious youth2 years ago
Hi,
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.
alright then cheers mate keep up the great ideas :)
milli092 years ago
"Electric Chair" Sounds a tad unfriendly, Don't ya think? lol
perhaps name it a seated segway ?
ScitechWA (author)  curious youth2 years ago
Lol. Yep didn't think of that but we don't have the electric chair over here.
And can't use the name Segway!
Curtis 1092 years ago
Hi Rodney,
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.
Prototyp 812 years ago
segway 2.0 :)
wootin242 years ago
Hi, i was wondering about the motors used in this project. do i have to use geared motors or can i just use a 300 watt scooter motor to drive it. thanks
fredbana2 years ago
This is fantastic iwas wondring when would you guys have the new code i'm building one of this for my kid i'm sure she would love it i hope i can get it done by x-mas
clazman2 years ago
This is great! I'd love to modify my wife's "Redman" power chair. At times power chairs as hers are somewhat scary traversing curb-outs. Once I wished we could have afforded an Ibot. But like the Redman at $30,000 was out of reach. The Redman is a standing/reclining chair. which adds a a degree of complexity or does it?
ScitechWA (author)  clazman2 years ago
There is nothing more stable than having 4 wheels on the ground.
Oh I agree, but the Ibot broke that barrier, although I don't know how well. I was able to observe one in use in a waiting room while I waited for my wife to complete an MRI.

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.
kelseymh3 years ago
A technical comment. This is an awesome chair. If a real wheelchair user wanted to use it, they would have to have some way to support their legs. You might think about how you could add a lightweight frame (some bent tubing and footpads) while still maintaining the balance and stability, for version 2.
Wragie kelseymh3 years ago
Having been stuck in a damn wheel chair off and on while this would be a hell of a lot of fun it really isn't suitable as one. It simply too low for a handicapped person. Standing I'm just over 6 foot. In a chair you come up to peoples bellys so about 4 ft. And even that is too low to reach for things set for normal access. Trust me if you ever want to get your eyes opened on what a pain it is, borrow one for the day and strap yourself down (so you can't cheat) and try it around the house and if you are brave the super market.
clazman Wragie2 years ago
Have you looked at standing / reclining power chairs such as the "Redman" made in the States?

We bought my wife one and it is great!
kelseymh Wragie3 years ago
I am pretty confident that these folks did not design something for a wheelchair user -- rather, they designed a chair with wheels. I do suspect that if they replaced the small tires with proper high-strength wheels (say, from a Quickie sports chair), it might be an interesting option.

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.
Well, while you may hate trusting it, The Segway has worked almost flawlessly with respect to your concern. It has redundancy to warn of problems and I am unaware of anyone getting thrown off due to a problem with the "dynamically compensating Computer" partially as I said because it is computers, plural.

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!
This is definitely a very cool project, which I've said multiple times in this discussion.
Wragie kelseymh3 years ago
I actually just had responded to the one comment on using it for a "wheel chair" by a poster. To me it sounded like he did want to try it as a mobility, that was the way I read his post. As I said as a fun thing it would be a blast to zip around in. Not everyone you see in a chair is 70 years or older some of us are in our 40's and still dumb enough to want to play with these other things, Me I still want to build a unicycle, the big wheel one. If you borrow the levelling /balancing it might even be ridden able by mere mortals. ;-]

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.
kelseymh Wragie3 years ago
I'm pretty sure you were responding to my own post, and correctly :-) I had commented that the pictures didn't include any kind of foot/leg support, which would be needed by a real chair user.

"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.
ScitechWA (author)  kelseymh3 years ago
Thanks for the replies guys but I think we are getting off topic here!
I don't want to get into the politics of medical insurance!

I hope you understand.
I promise not to rant on about insurance or insurance sales droids without mentioning the use of chainsaws, axes or a industrial wood chippers. ;-]

Seriously you guys have something here that is just so damn close to being a real godsend to some people. You do need to realize that and keep it in mind.

Cheers
love4pds Wragie3 years ago
it would be a godsend to me. I am one of the people that could use that. People forget that there are disabled people that can walk for short distances even without limps but not farther. I cant go shopping but can walk around the house. Even store forget people who just use cane and put handicap parking far away from doors assuming all disabled have wheelchairs so don't need to be close. So they put ramps down 5 -7 parking spots. Disabled doesn't fit into "70 year old people" boxes in wheel chairs. and I just after 8 years of fighting with SSD got approved last week and now have 2 years to wait for medical and cant afford ANY treatment or ANY affordable assistive technology such as a scooter for shopping or help to drive (cant do that either). All because I didn't fake a limp. 4 of my treating doctors wrote I am permanently disabled, but it is invisible so the SS (remind you of anything) docs talked to me for 2 minutes and decided I was fine, didn't even look at my 8 swollen surgery sites and my implanted battery. So I have to wait 10 years for medical or any assistive tech! I would love to have a cheaper option even if it came with more warnings, they cant be more than the list of warnings on medicine commercials...lol
Sorry, I know off subject, but couldn't resist,
CJ
ScitechWA (author)  love4pds3 years ago
Yes it does look like it can be a godsend to some people.
It wasn't designed for that purpose but it does look like we have stumbled upon something of interest here.

I hope this Instructable does people ideas for thier own designs.
Glad I could inspire!
Wragie kelseymh3 years ago
The shame about it is very innovative things like this will never make the leap from toy to tool as a result. I had meant to say to the guy(s) who wrote this I hope they keep it in mind there is a huge market for assist devices and there is money to be made and people that can be helped at the same time. And I did get off track by not saying that. Initially ;-] Actually thinking about it you could add a safety wheel fore and aft and it would work for some people. If it had the range (without having to stop off at the construction site along the way ;-]) It would make for a very fun run around.
ScitechWA (author)  Wragie3 years ago
It's all good.
It can be changed to suit all people.
Without the chair it costs about $400-$600 build.
The carbon fibre chair we already had.

ScitechWA (author)  Wragie3 years ago
In no way was this designed as mobility device in mind.
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.
This is an awesome project, as I said. When you've had a chance to upload photos for all the steps, please send me a PM. Thanks!
To be fair to them it does have a footrest in the video clip. Also has a pad behind seat to stop it falling back and cracking head of the rider.

I really like this, although I would say that wouldn't I !
ScitechWA (author)  kelseymh3 years ago
The chair was built for a DIY Fair at the end of the year.
We won't be changing this chair but yes it would be possible to have supports to hold the legs.

Balance and Stability isn't an issue!
We were so pleased with the stability chair.
Once the balance point gets adjusted you can use head movement to drive it forward and backward.
Joystick drive is still in the testing stage at the moment.

As for version 2 well it's a Lazy Boy recliner.
It has the leg support built in.
Coming Soon!
Curtis 1093 years ago
How exciting, I just come back from the Nutty Professor Exhibition in Harvey and your chair-segway looks great I didn't have a go at it myself as I was more interested in the Standup-segway. I spoke to Paul and he explained it in great details to me and he had a job getting me off it again..... He said I would find all the details on the Instructable web page. The Chair is described in details but not the standup one. My question is could I use the same mechanics for the stand up ons as you have used for the chair one regards balancing etc?
Well done
Regards
Kurt
ScitechWA (author)  Curtis 1093 years ago
Hi Kurt,
Glad you enjoyed Nutty Prof expo!
Due to being our super busy period at work and also building stuff for nutty professor, I haven't had time to finish the stand up scooters yet.
I will have it out very soon.

They are exactly the same as the Balancing Skateboard!
Same code, same harware.
You basically just have to move the wheels apart, turn the board sideways and put a handle post on it.

Rod
ehigson3 years ago
Is it possible to have the seat higher? or would that ruin the balance?
ScitechWA (author)  ehigson3 years ago
We have tried it with a milk crate on top of the frame and it didn't change a thing.
It doesn't seem to affect it at all.
Of course having a low center of gravity would be preferable.
thanks for the reply. i'm only thinking of raising it high enough to fit the battery and the electronic components under there so it should still have a fairly low centre. and also what is the battery life like on the scichair?
ScitechWA (author)  ehigson3 years ago
The battery we have is a drill battery.
NiMH 18Volt 3.0Ah and lasts about 30 Minutes.
AlexBau3 years ago
Nice job!

>>I have added 2 extra wires and resistors for a later code change
>>to be able to drive it forward with the joystick.

Could you please share this part of the code and electonic (joystick) connection to the Arduino?

Thanks!
ScitechWA (author)  AlexBau3 years ago
We are still working on the code and will have it available very soon.
It will be a proportional control too.
eg a pot style joystick.
How fast does it go?
soundmotor3 years ago
WALL-E FTW!
love4pds3 years ago

Awesome!!!!!!!!!!!!
ScitechWA (author) 3 years ago
Hi Everyone,
I have updated some of the picture to it's current workings!
More will be added as soon as I get a bit of time.

I missed that the original picture didn't have the foot rest, the arm rests and rear skid bar.
As a Science centre we build this for a bit fun and to show to others something different than a standup balancing device.

I have had comments of people that this would be good for somebody in a wheel chair, which it would.
Not practical for everyday use probably, but a version with larger wheels or even a mechanism that allows them to stand upright for dealing with people at counters etc.

I do find this quite low and people do walk in front of you even after looking at you first. So I can understand where wheel chair bound do get frustrated.
I have a friend who is quadriplegic and his custom chair cost him $8000.

We will be taking these type of inventions to school to show kids what can be made and it's not that hard. A bit of inspiration!

A real Segway has 20 micro controllers for control and backups for them.
They have 5 Accelerometers set a different angles for fine tuning.
The motors they use are 2Hp brushless motors with zero backlash gearboxes.

So they are quite advanced compaired to our chair.

We have 2 Genuine Segways that we allow Adults to drive around our centre.

You could alway have a wheel at the front and drive it as a trike and then kick in the balancing for a bit of fun!

The battery last about 30mins of driving around.

It is quite stable to drive but needs to be geared up a bit for more speed to help with drivability.

Please continue posting but can we refrain from any comments that may affend.
agis683 years ago
excelllent work...i will try to make one.....what about the cost of it?
ScitechWA (author)  agis683 years ago
Without the chair it costs about $400-$600 build.
Well i made my own plan by eleminating the self balence so my plan is around $180
for this masterpiece its nothing!!!!....thnx......
boston75133 years ago
Watched the video here and I can't help but think that this could be useful for ( some ) folks with mobility disabilities
firepup1043 years ago
I was wondering sience im not going to make it ballance im just going to put a third wheel on the back Whould i not need arduino or anything else.
You wouldn't need the self-balancing code, but you would still need a way to switch power to and from the motors. If you want nice controllability, that means a way to either vary the current to the motors or vary their power using PWM.

If I were to make a three-wheel version of this (and with the cool self-balancing code already done, why not just do it that way?), I would still use an Arduino or PIC to control the motors (via a series of FETs or something, since an Arduino or PIC could barely handle switching 400mW by itself (you'd have to use a large PIC and switch several pins together), let alone 400W.

Besides, if you built it with a third wheel but stuck as closely to the original design as possible, you might be able to swap XenonJohn's balancing code in and take off the third wheel at some point...
thanks
geppetto4253 years ago
Awesome to the 10th degree but we can't hear a word he's saying....
Phil113 years ago
Very cool! I'm guessing some people who use wheelchairs would be interested in your sports off road model which you've still to make, right?
Has Dean Kamen seen this?...
kelseymh3 years ago
This is so close to being a Featured I'ble!

You need to add pictures to the three steps which don't have them. Please, please, add a set of photos of the components to Step 2 (your own photos for the big stuff, steal some obvious clip art for the little things (resistors, tape, blah blah blah) and of the tools you used to Step 3. On the final step, you could add a picture of the chair in action.
ScitechWA (author)  kelseymh3 years ago
Photos are coming!
There will be more updates soon and the format tweeked up a bit.
Video on the last section is added!

Thanks for the comments.
+1