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Author Topic: How to hack an electric wheelchair controller?  (Read 5005 times)
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I'm working on a lab project and I must control an electric wheelchair. I openned the control unit and found a 5-way connector like this

http://www.digikey.pt/product-detail/en/B5B-EH-A(LF)(SN)/455-1614-ND/926522

but I dont know what pins does what? So does anybody know how to check that? The controller is like the one attached.
Thanks for the help.

* DYNASharkRemoteweb (2).pdf (272.78 KB - downloaded 49 times.)
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Left Coast, CA (USA)
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Not nearly enough information for anyone to really help you I'm afraid. What is need is a detailed manual on the thing the hand controller plugs into:

Quote
Fully compatible with all Shark Power Modules

So find a detailed manual on the specific 'shark power module' you have and maybe it will have enough electrical information to be of help.

Lefty

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Siena Italia
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The Dynamic Controls Shark, as with all recent wheelchair controllers, uses a proprietary version of CAN bus.  If that connector is for the cable from the joystick pod to the power module, and you want to interface with that, you will have to do so using CAN bus serial communications.  That also means that you would have to "sniff" out all of the CAN messages that the Shark system is using as Dynamic is not going to tell you what they are. 

If that connector is a joystick-pod internal connector that connects the joystick to a circuit board, and if all 5 leads are in use, and you can't find some one who knows what the Shark uses, you may have to measure voltages from each to ground to figure out what each is carrying as there are a variety of Hall-effect or inductive joysticks in use in different systems.  At a minimum, 4 leads are needed for a two-axis joystick: Vcc (usually 5V), GND, X output (variable, often something like 0.5 to 4.5 V, with out of range being sensed as a failure), Y output.  A fifth lead could be a number of different things depending on the joystick: Vref (midway between Vcc and GND), or a center-detect signal, or other.  If you google for "Apem", you can get an idea of the range of joysticks produced by one manufacturer that sells to the wheelchair controller industry.

You might also want to post your question at http://www.wheelchairdriver.com/board/ and ask if anyone there is familiar with Shark internals.  I have a fair knowledge of some of the Dynamic DX modules, but not of the Shark.

Ciao,
Lenny
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Hi. Thanks a lot for your response. It helps me a bit more to understand what I'm facing. When I openned the controller, I saw that form the joystick there was only 2 wires coming out from him, and under the joystick, there was 4 things, like coils but more circular and smaller. I would love to insert an image but I cant figure how I do that. I click on the button but I dont understand what more I have to do.
Thanks again for the attention.
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Siena Italia
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That is an inductive joystick.  There is one moving coil (the first 2 wires you talk about come from this) and four fixed coils.  The moving coil is excited by a voltage, and the fixed coil sense the position of the moving coil.  That joystick will also contain a small circuit board that will convert the outputs from those fixed coils into a variable voltage.  For what you want to do, you should NOT be fiddling with what's inside that joystick can.  You can "mimic" its outputs by feeding voltages to where it's external wires connect - but you have to figure out what those wires are as described in my previous post.  I am assuming that the connector you showed us goes from the joystick can to the circuit board inside the joystick pod.  If you are comfortable using a multimeter, and are careful, it isn't difficult to figure out what those wires are.  If you go to the WheelchairdDriver forums you will find a number of threads on this theme, so you really don't have to re-invent the wheel.
Ciao,
Lenny
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