Instructables
Picture of Psycho Scooter Scramble


Psycho Scooter Scramble is a blind-driving electric wheelchair game. It consists of two riders, strapped into electric wheelchairs, and two blindfolded pilots, who remotely control the wheelchairs from the sidelines based on information given over headset by their driver.

The basic mechanic is simple: players must drive across the court to get a ball from a stand, then drive back across to put the ball in a
hoop. This action is repeated until all four balls have been scored or the timer runs out.

Since there is an inevitable disconnect between the pilots’ steering and their teammates’ intentions, wheelchairs zigzag across the court at high speeds, colliding with each other, ball stands, the scoreboard, and most everything else; all the while, taking full advantage of the custom steel bumpers.

Psycho Scooter Scramble was created for the Creation Challenge. Team Instructables includes Amanda Ghassaei, Audrey Love, Eric Wilhelm, Gabriella Levine, Greg Johnson, Jake Rogers, Jessy Ellenberger, Matthew Dalton, Noah Weinstein, and Randy Sarafan.
 
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Step 1: Go get stuff

Picture of Go get stuff
You will need:

per cart**:

(x2) electric wheelchair
(x1) 1"x1"x10' square steel stock
(x1) 2.5"x.175"x20' steel flat bars
(x1) Arduino
(x1) Wireless SD Shield
(x1) Xbee S1
(x1) PC Board
(X12) male header pins
(x4) relays
(x4) 2K resistors
(x4) 1K resistors
(x4) 5.1K resistors
(x1) 9V battery connector
(x1) 9V battery
(x1) 22 AWG stranded wire
(x1) wireless headset
(x1) Large-ish sealable plastic food container
(x1) assorted zip ties

control pedestals:

(x1) Arduino
(x1) Wireless SD Shield
(x1) Xbee
(x1) 9V battery connector
(x1) 9V battery
(x1) 4' x 8' sheet 3/4"wood
(x2) floor flanges
(x2) 1/2" threaded metal pipe
(x2) 24" x 24" acrylic sheet

scoreboard:

(x1) 4' x 8' x 3/4" plywood sheet
(x4) flanges
(x2) 48" threaded pipe
(x2) threaded nipples
(x2) elbow joints
(x2) small whiteboards
(x4) 36 x 24" 1/8" black acrylic sheet
(x2) 36" x 24" x 1/8" orange acrylic sheet (for lettering)
(x2) 12" 7-segment display
(x1) Arduino
(x1) Annoying buzzer
(x1) Light-up stop hand
(x1) Red arcade button
(x1) green arcade button
(x1) PC Board
(x1) 5V relay
(x1) 5V / 120V 10A solid state relay
(x2) giant 7 seg display
(x2 darlington uln2803

goal:

(x1) 8' x 4' x 3/4" plywood board
(x2) Basketball nets
(x1) Staple gun

ball holders:

(x8) Kick balls
(x2) 4' x 8' plywood sheet
(x2) 4x4 wood beam
(x4) 2x4 across
(x1) 20' thin metal rod

miscellaneous:

(x2) referee shirts
(x2) whistles
(x1) 1 yard of bright orange fabric
(x1) 3' dowel rods

**Cart materials are for ideal conditions. Parts may vary depending on the electric wheelchair you are confronted with.
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nmsr119610 months ago
For a clearer understanding of the joystick connectivity. Do you have a clearer wiring diagram? if not, my questions below:
The (+) and (-) under wheelchair - is that the vcc of the wheelchair console controller (where joystick is)?
and;
The relay , Is that connected to the arduino I/O pin(s)?

Thanks ( in advance)
Godblessed11 months ago
Hi, I was just wondering if you can assist me in understanding the controllers to wheelchairs. I am an electronic tech and I have several friends that use mobiliy scooters in which the controllers are bad. Any information that you guys can give would be highly appreciated. Just need to know what are the basic things that I would need. Not really trying to hack into or change anything to the controller, just need to set up something simple to test the operations of the device.
I've got a wheelchair with a joystick similar to yours. Its 6's wires; 5v, Gnd, 2 for Left/right, 2 for forward/backward. The two for left/right forward/backward are paired (i think like yours) as one rises, the other falls, and they balance at 2.5v for center.
I tried wiring an arduino up to all 4 pins and simulating it (with the same voltage and amps for the center) but the wheelchair somehow still knew it was not the correct joystick. How would i go about hooking up an arduino in place of the joystick? I cant find anything online about it except for this instructable and this mention (http://www.rosstron.com/dl_50_specifications.htm) of the electric wheelchair box that's similar to mine. Thanks for your time, awesome instructable too!!
shtranka1 year ago
thank you,and in my project i will leave the joystick connected ann add the arduino, but if both of them are working , is that a problem, if yes any solution to keep only one of them working
shtranka1 year ago
hi , i just want to know if you used a transistor to command the relays or what!
the relays are connected directly to the arduino digital output pins
shtranka1 year ago
hi, i m going to command a wheel chair using arduino but i can.t figure how did u make the connection between the arduino and the relays?? don.t you need uln 2803 and potentiometrs to deliver the values required? and i'l use arduino DUE is that possible ? because i 'll use a 5v sensors that can.t handle. so would you plz help me up by explainning the circuit you add to the arduino and wich pins did you used. thanks :)
the relays we used operate on 5V, so no need to use a uln2803. looks like the due only outputs 3.3, this will not work with the 5v relays. I would recommend using an uno. the schematic is in the step.
dany1511 year ago
hey ...my wheelchair run very fast ... i made as mentioned in your project...anyway to make it slower ?
change the values of the resistors so that the voltage going into the wheelchair control is closer to 2.5V
uneakone1 year ago
Hi all,I know I'm getting to this project a bit late, but I have been trying to figure out what I am doing wrong. If anyone can get me pointed in the right direction I would greatly appreciate it. This is what I have.... I built up the circuit board with the total of 4 relays on it. From the joystick I have the plus voltage going to the 5 volt pin on the sending arduino, the minus ( or negative) going to the gnd pin on the same arduino. I also have one of the signal left/right pins going to analog A0, and one of the signal forward/reverse pins going to analog A1.

For the Receving arduino board combined with the circuit board I made I'm having trouble with the hook up. I thought the output of pins 4,5,6,7 would ave gone to the relay + and the negative woud go to the arduino gnd, but with this hookup when I toggle the joystick all the relays seem to go on so I know that's not right. I also have the Receving arduino + 5 volt going to the + side of the two 2K resistors, and the gnd to the - side of the other two resistors.

When I plug everything in I do get a reading of 2.5 volts on all four signal pins referenced to the gnd pin on the arduino which is tied to the negative side of the relay.
When I toggle forward I get 1.2volts on both of the forward/reverse signals, and the left/right signals increase to around 2.6 volts. When I toggle reverse I get 3.8 volts on both of the forward/reverse signals and again the left/ right pin voltages increase slightly. Do I have any of the connections right? The controller that my chair came with is a dynamic DL 5.2i so it only has 6 wires going to the joystick (4 directions and +/-.) hopefully someone out there has some experience with this type of controller.

Thanks Kim
dany1511 year ago
Dear amanda
do you mind if add my code for control the wheelchair ?
Raynentye1 year ago
I decided to try this out seeing as how I have a powered wheelchair that was given to me. I'm having a problem with the Center Tap pin. On your diagram it says, "Might need 1K -2 K". I've tried practically every resistor in between with no success. Every time I turn on the chair it gives me a "Joy Stick not centered" warning and doesn't allow me to move the chair. Any luck with a particular resistance? I was thinking on trying a 3K ohm potentiometer adjusted to equal resistance and voltage balancing. Any assistance would be greatly appreciated!
Raynentye
you can solve it by using different resistors...like 1K and variable resistor for the center

1K====>--(measure voltage here)--<==== variable resistor

then change the value of the variable resistor until get 2.5v

I pulled apart my breadboard in a tiresome rage last night and took a nap. I then decided to attempt a "parallel re-engineering" attempt. Took some measurements on the main joystick and viola! I came up with this:

I have two joysticks for my wheelchair: the primary for the person who is in need of the wheelchair and an attendant joystick for someone that's accompanying the driver for a "walk". Seeing as how I only need one joystick on the chair itself, I figured I could keep it there! I don't need to worry about "balancing" the center pin voltage because the joystick will never leave the system, let alone the center. I removed the attendant joystick for my remote Arduino/Xbee set up and soldered a wiring harness in parallel to the primary joystick. In order to move the chair in either direction, put a 100 ohm resistor in series with the positive, and another 100 ohm resistor in series with the negative. I combined the left/right pins with eachother and the forward/backward pins with eachother. then its pretty much just a simple H bridge wiring from here! Apply the 100 ohm resistor-in-series positive to the forward/backward pins and it goes forward, apply the 100 ohm resistor-in-series negative to the forward/backward pins and it goes backward!
Apply the 100 ohm resistor-in-series positive to the left/right pins and it goes left, apply the 100 ohm resistor-in-series negative to the left/right pins and it goes right!

This simple circuit/joystick combo can easily be stashed behind the seat where the victim, I mean player, will not be able to reach it while the game is being played!
Or you could just really freak out Grandpa before the Holiday feasting begins!

Thanks for the awesome Instructable by the way!
dany1511 year ago
if i donot use the xbee ...what are the changes in the code pls???
dany1511 year ago
if i donot use the xbee ...what are the changes in the code pls???
Xagormax1 year ago
On the receiver side, are pins 4,5,6 and 7 the arduino pins that control the relays?
Also, the 2K resistors are connected to + and -. I assume this is the 5v supply on the arduino?
dear Xagormax ...i think those pins are for serial comuncation between the arduino and the xbee .....
for the 2K ..yes
dany1511 year ago
dear amanda
i got arduino-mega2560 without Xbee,and i wanna configure it to accept signal from EOG device (EOG == Joystick)....to which port i connect it? and can i use same code?
i think it need some changes right?
can u help me pls
dany1511 year ago
nice..work
but i couldnt figure out how you connect the 2 joysticks with ardunio!!!
pls add more detials about joystick hack...or send to me at
engmoh81@yahoo.com

Eagerly wait for your answer
The two inputs from each joystick were connected to the arduino like this:
http://www.arduino.cc/en/Tutorial/JoyStick
thnx for reply ...and i wanna ask one more question pls
in my project i will leave the connection of the (vs,Vs/2,GND,Not connect)wires...
cut the (forward,back,right,left)outputs wires
then connect them to the relays as u did in your project ,and the other side to
micro controller .....
and leave the ((forward,back,right,left)) from joystick side not connected
i think this will make the controller work because it must see the joystick
and will not give error in connection...
is it ok?

if im wrong ....pls advice me ....cause i don't hv spare parts...
my regrds....

i will be happy if you add me
engmoh81@yahoo.com
are you hacking a wheelchair or are you just trying to use a joystick with arduino?
I'm hacking the wheelchair i will use Electrooculography (EOG / E.O.G.)
to control the Wheelchair ...so that i must replace the joystick with the signals
coming from eyes Muscle via EOG...
i will use Arduino to translate the signals to the wheelchair
it is clear now?
for the circuit below
http://www.instructables.com/files/deriv/FMY/N3TU/H4ZN57K6/FMYN3TUH4ZN57K6.LARGE.jpg

if the two relays on 2k//2k+1k ===) 2.5 v
if both off 7.1k//7.1k+1k========)1.1v
if one off and other on 7.1k*2k/7.1k+2k=1.56======)2v

the jc2000 output in forward =4 v
in center=2.5v
in backward=1 v
------------
so i couldnt get the 4v for the forward state !!!
is the 2v enugh for that???
randofo (author)  dany1511 year ago
Both relays should never be on. Both should always be in the off state. 2.5V is neutral.

You are mostly right, but missing an important thing...

If relay 1 on and relay 2 off, it is --- 2K to 7.1K

If relay 1 off and relay 2 on, it is --- 7.1K to 2K

You should be able to get about 4V from this setup.
i didnt understand this

"If relay 1 on and relay 2 off, it is --- 2K to 7.1K

If relay 1 off and relay 2 on, it is --- 7.1K to 2K "

both states give 2 volt at the output ,how can i get 4 V ???
the purpose of the relays is to short circuit the 5.1k resistor it is attached to, effectively removing it from the circuit.

when both relays are off you have:

0V----2k----5.1k--(measure voltage here)--5.1k-----2k-----5V

since there is 7.1k on either side of the point you are measuring, the voltage is half of 5v = 2.5V

if you turn on one relay and keep the other off you have:

0V----2k----relay(0ohms)--(measure voltage here)--5.1k-----2k-----5V

in this configuration there is 2kohms to ground and 7.1kohms to 5V, this causes the voltage at the place of measurement to drop to 2/(2+7.1)*5V =1.1V

if the state of the relays is switched we get:

0V----2k----5.1k--(measure voltage here)--relay(0ohms)-----2k-----5V

now there is 2kohms to 5V and 7.1kohms to ground, this causes the voltage at the place of measurement to drop to 7.1/(2+7.1)*5V = 3.9V

the reason we don't turn both relays on at the same time is because the circuit would look like this:

0V----2k----relay(0ohms)--(measure voltage here)--relay(0ohms)-----2k-----5V

now there is equal resistance on either side of the measure junction, this gives us a voltage of 1/2*5V = 2.5V, same as what we get when both relays are off. this is just redundant, so we don't need it.

hope that's clear!
yup...yup...it is clear thank u very much

now i will applay the 5v dc from microcontroller pins ----to------> this circuit of voltage divider---to------>joystick controller board
for the 4 pins (f/b out1&2,r/l out1&2)

connect the vs/2 as your divider circuit

keep the connection of jc2000 ===>3 wires (vs,gnd,not connect)...
or remove them ????

how to mimic the joystick signals with an Arduino ??
connect pin 3 to ardiuno gnd, leave the rest unconnected
okay...
now i dont hv an experience with Ardunio ..can i use another PIC ,like 8051 microcontroller? isit need ADC ?


in my work it is no need to use xbee radio....

there is any other process in ardunio ??
you need ADC to read the input from the joysticks. But the circuit with the relays, which is hooked up to the wheelchairs, is all digital.
i will take the input signal from EOG ==>ADC==>PIC 8051==>wheelchair joystick controller

or it need to connect the jc2000 joystick?

what is eog?
see this site

http://en.wikipedia.org/wiki/Electrooculography

and tell me if it is need to connect jc2000 joystick or not? cause the wheelchair
joystick controller will not work if joystick not connected ???
is the microcontroller will act as a joystick ? is it need another setting?
the microcontroller acts as the joystick. In this case you will not need to use any joystick, just send data from the EOG to turn off/on the appropriate relays in the circuit above.
that is good ....thank you amanda .... i will make this circuit tommorrow...thnx for your help again ...see u
dear amanda i got this error
A joystick fault is indicated.Make sure that the joystick is in the center position before switching on the control system !!!!
is it voltage drop? or current problem?
when the arduino boots up, make sure all the relays are off, then turn on the wheelchair
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