Hacking an Invacare Pronto Electric Wheelchair - Part 2
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- เผยแพร่เมื่อ 5 ก.ย. 2024
- The joystick on the wheelchair turned out to be connected with a 6-wire cable and probing the signals on that cable with my oscilliscope turned up something that looked a lot like a 9600bps serial data feed. After a few hours of analysing the data flow from the joystick (and a lucky pdf find) I managed to send the right data to get the PC recognised as a 'System Attendant' secondary (overriding) joystick.
This is a new world I'm discovering.
I just bought a used M91 with a SPJ+ joystick. When it powers up the battery indicator lights all turn on from left to right then go off and the wrench flashes 9 times. I can see comm signals coming from the joystick on an o-scope but it immediately goes into this error mode. Any thoughts or help would be appreciated.
Hi Jim ! I am enjoying all your videos, great fun to watch the curious mind work ! Thanks for spending the effort to let the rest of us watch. I am controlling a Jazzy wheelchair remotely but am ashamed to say I am doing it by having servos moving the joystick. I was discouraged by the control signals running through the 4 pin cable connecting the joystick to the base. You have solved the problem. Is there an "attendant port" that you tap into or are you paralleling off the cable from the joystick to the base?
Hi Rob. I just spliced into the 4-way cable. The system uses an RS485 serial bus (a lot like RS232, but supports having more than two devices connected at once). I did a bunch of work on decoding the signals being sent over the wire... got really close to having it working and then an insider sent me a copy of the SharkBus protocol so I could finish the job. If you send me a private message with an email address to send to, I can reply with a copy of the SharkBus protocol and my example code in Python and C++ for sending and reading the SharkBus commands. I was just using a little embedded linux PC to send the messages to/from the bus... it worked pretty well until the CPU started to get bogged down, and then it would miss the very precise timing requirements of SharkBus and the controller would indicate an error that required the wheelchair to be power cycled. Would love to see a vid of your Jazzy sometime.. Cheers!!
We found one of
These sitting at a dumpster . It turns on . But it’s doing the same thing youres is at the end ? The light is moving like that n the light around the
Horn is on
The communication protocol between the joystick and the motor controller has very tight time constraints and if the messages from each other do not appear on the bus at the correct times then the unit goes into a shutdown condition like the one you're describing. I'd suggest checking the wiring from the joystick, clean the connectors etc - If you have an oscilloscope you should be able to monitor the messages being sent across the SharkBus. It's been 9 years since I last messed around with this, so I'm afraid I don't have much more in the way of debugging advice. The sharkbus protocol is available online blog.arisux.com/wp-content/uploads/2021/01/Shark-Bus-Communications-version5.pdf is you're willing to deep-dive into finding the problem. Hope that helps. Cheers!!
Jim,
Good news!
I found the exact wheelchair you are using!
now the easy question...
which 2 pins on the front charger port are the RS485?
thanks!
Doyle
Hi Doyle - I'm not sure about the pins on the charger port. I tapped into the wire going from the joystick to the motor controller and soldered into the signals from there. That wire just has Power, GND, D+ and D- connections, so it was easy to work out what was what. Cheers!!
Thanks!
I will look for those points on the joystick board!
Best
Jim Conner
looks like my joystick is SPI bus
any tips out there to help?
Hey Jim. I know this project is a little dated but I'm trying to hack an Invacare SPJ joystick and would love to have a copy of the SharkBus protocols. Any chance of getting a copy?
Bruce
Hi Bruce - Can you send me a private message with your email address, and then I'll mail the goodies over to you. Cheers!!
Hello Jim ! Great Videos... Im trying to get a wheelchair automated. Do you have any documentation about how you hacked the controller ? I have a raspberry Pi that I would like to use to control a similar wheelchair with the SPJ controller. I wish to use the technique for the System Attendant as well.. If I send a private message will you be able to send the sharkbus protocol as well? Thanks in Advance.
Sharkbus protocol spec document is not super-secret anymore, so I added in my github a few months ago... github.com/jimconner/sharkbus ... Good luck with your project. Cheers!!
Nice to see the hacking demo, but why can't you publish the details too? What is the pin-out of the connector from the chairs joystick to the control box? What volts, baud, which pin is ?Volts, Gnd, D+ and D-? R4RGuy@g wants to re-purpose a donated chair to be a robot platform, then maybe even repair the chair for somebody else to use for mobility.
My code is all up on github at github.com/jimconner/sharkbus already.
That is a bunch of Python software, I'm looking for the pin definitions so I can use a RoboGuts™ circuit board to control the chair. I'd really like to know the 15-PINs on the Pronto M51 control box.
Sorry - I've no idea about the control box connections... I just hacked my way into the 4-wire data cable which just had power, gnd, D+ and D- pins and worked on it from there with RS485 serial driver. Cheers!!
Hi Jim , I also am trying to remote control a Invacare TDX would you be willing to share your notes with me?
Thanks in advance..
Hi Kenney - I'm happy to share my code and notes... Send me a private message with your email address and I'll mail over what I've got. Cheers!!
Thanks to Jim i had success with a Jazzy 600 www.wheelchairdriver.com/board/viewtopic.php?f=2&t=4867&start=400#p83750 The code is there if you want it, not sure what a TDX runs on though.
@@ThingsWhichArentWork Hi there! Awesome job! Also really interested in the code or additional info to replicate this
that fancy equipment looks like the average person won't have,