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Thread: Smartdrive pressure switch changed to clamshell switch DIY

  1. #1

    Smartdrive pressure switch changed to clamshell switch DIY

    It's been no secret that I have not been happy with the dual pressure sensitive switches.

    One of my reasons for going to the San Jose Abilities Expo was to discuss with Mark of Max Mobility my difficulty with them. Mark said two things. First was that I had the shiny ones that were supposed to be replaced with better ones. Which he did on the spot. We traded switches and he gave me instructions on their use.

    Duh, these did not seem much different than the last set, but I went for a test drive anyway.

    I rolled back and told Mark I wanted something that gave me bio-feedback when I pressed the switch. His response was that my problem was that I had the switch in my lap instead of mounted to the frame. No you don't understand I said. I want a click, like the previous clamshell switch I had. To that he said, "You can use any momentary contact switch you want. Radio Shack has them." "Great give me back the shiny switches, I want to take them apart to find out which wires go where." He did exactly that. He went to the garbage and pulled out my old switches and handed them to me. So I left there with my old switches, two new ones, mounting Velcro and Mark's permission to hack into them.

    It turned out to be quite simple. And to keep it simple I will post the "before" picture which shows a switch opened up, a "rewired" picture which shows a clamshell added to that switch, and a "finished" picture which shows the clamshell, the old switch that houses just the light, and a stub where the other switch was.

    First the "before": Notice the three wire connections. The top red wire is LED. The middle blue wire is ground, and the bottom wire is switch. The middle and bottom are the locations that get used in the "rewired" post up next.

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    Last edited by nonoise; 12-18-2014 at 03:38 AM.
    I have had periodic paralysis all my life. I lost my ability to walk in 2011 beginning with a spinal block, which was used for a hip fracture caused by periodic paralysis.

  2. #2
    Once the switch was apart a plug for another wire cable magically popped out the opposite side. So I figured I would disable the original switch and hop on out the new hole with another cable for the clamshell switch. Luckily I happened to have a Smartdrive clamshell from an earlier update, so no need to hunt down a satisfactory momentary contact switch like Mark was talking about.

    Getting that stuff back together in the switch housing required cutting away the backside of the original pressure button to make space. I also flipped over the pc board which minimizes accidental contacts. There are other ways to skin this cat though. Due to alignment, my method made me modify the insides for the LED to shine.
    This is the rewired switch:
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    Last edited by nonoise; 12-18-2014 at 03:40 AM.
    I have had periodic paralysis all my life. I lost my ability to walk in 2011 beginning with a spinal block, which was used for a hip fracture caused by periodic paralysis.

  3. #3
    What you see is the clamshell on it's side at the bottom of the photo. The original button only serves as an on light which I mount permanently to the battery with Velcro. The dead end, is exactly that. I cut the other switch off and sealed the wire with shrink wrap. I just clip the switch to my clothes. Nothing has to stay on the chair.

    I know how crude this "finished" project looks, but it *works* I don't have to fuss with that damn unknown pressure button any more. One click and I've got it. I don't know why Mark doesn't just supply both.

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    Last edited by nonoise; 12-18-2014 at 03:41 AM.
    I have had periodic paralysis all my life. I lost my ability to walk in 2011 beginning with a spinal block, which was used for a hip fracture caused by periodic paralysis.

  4. #4
    Nice mod
    Chas
    TiLite TR3
    Dual-Axle TR3 with RioMobility DragonFly
    I am a person with mild/moderate hexaparesis (impaired movement in 4 limbs, head, & torso) caused by RRMS w/TM C7&T7 incomplete.

    "I know you think you understand what you thought I said, but what I don't think you realize is that what you heard is not what I meant."
    <
    UNKNOWN AUTHOR>

  5. #5

  6. #6
    Senior Member grommet's Avatar
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    I've been using a SmartDrive since it's very beginning and gone through all the switch changes. It's taken some getting used to each time but I have completely made the change over to the bump switches. At first I did want a click like the previous switches, it's positive feedback that a change has been made but I am well skilled with the most recent bump switches. They work fine for me. A couple problems with the click switches was the very very light pressure in the first series. Accidentally setting them off was terribly easy and caused me many problems. The second series used a heavier spring and helped a lot but I admit once I got used to the bump (pressure) switches I think I prefer them now. Another problem was catching something on the edge of the switch paddle. It was a sharp thin edge and a finger might stick there or a bit of sleeve. Just for a moment but when you're moving that means distance.

    I can't speak for Mark as to why he does one thing or another but all my experiences with him show him to be very bright, totally committed to making the SD the best it can be and he responds to customer needs very quickly. It's all a complicated process and if you found something or a new way that makes the SD work better for you I am glad. I would hope you wouldn't second guess Mark on his decisions. He's doing what's best for a lot of people and that means the SD can't be all things to all people.

    One thing I would really like him to change is to have the indicator light on the forward part of the switch housing. It's hard enough to see it while sitting which is how users are positioned. Another .25 inch forward would help see past pant legs and fabric cushion corners.

  7. #7
    To clarify

    This was not a random hack or second guessing anyone. This was an authorized change to an already excellent product which I had temporarily stopped using due to my inability to properly control the new power switches. I had waited from August to October to get the chance to show Mark and possibly trade motors or whatever. He surprised me when he said all that was wrong was that I had first edition switches. But trying the ?new? ones he gave when I got there I saw essentially no difference. So I asked him, ?If I can?t get the SmartDrive turned off, can I just pull the switch cable out of the battery?? He said of course you can.

    It was then that Mark said ANY momentary switch I wanted to use will work. His remark surprised me because he just authorized me to modify the SmartDrive in this way. But the switch cable plug has three connection points. They go to the power light and the switches but I did not know in what order. So I needed the discarded switches as a wiring guide. Mark being a top tier manufacturer fetched it out of the garbage for me to use.
    I have had periodic paralysis all my life. I lost my ability to walk in 2011 beginning with a spinal block, which was used for a hip fracture caused by periodic paralysis.

  8. #8
    Senior Member ~Lin's Avatar
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    Nice! I'd really like some tactile feedback to know I've pressed. I STILL don't have my SD yet due to NuMotion fucking me over, but its finally being ordered next week. When I had the demo unit, that was the one issue I had was difficulty telling if I'd pressed or not, and having to press a few times to actually get it etc. But maybe my demo had the older switches too.
    Board Member of Assistance Dog Advocacy Project working in Education. Feel free to ask me any service dog questions!

    I am not paralyzed. I have a genetic connective tissue disorder with neuro complications and a movement disorder.

  9. #9
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    I just got my SmartDrive and already am having issues with the buttons. my feet have stopped my several times when I couldn't get the chair stopped in time and drove right into a closed door.

  10. #10
    Senior Member grommet's Avatar
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    I am sorry that happened. It happened to me a lot when I started using the SD. It has taken me a lot of practice to build up the skill to control the SD. Luckily now it has two modes, Indoor and Outdoor. I still want an improvement in the programming. Indoor mode is the safest. The trick there is to let the chair run without resistance any distance before you tried and stop it or it will think it needs to keep pushing. For example, giving a push and engaging the motor and immediately braking will keep the motor pushing. I crashed before I figured that out. Now I know, give a push and move even a couple of feet without trying to stop then when I try to stop the motor will disengage. Really wish I had known that at that time.

    Outdoor mode requires using a press of a switch to disengage and that's great. I've gotten much better at reacting and using the button. But my problem is that sometimes the drive will still seem to think it needs to go faster and seemingly suddenly accelerate. Then I have to quickly tap a button and give a push to re-engage the motors. That last part is hard when I am already moving, the motor seems to not want to engage while moving unless I give a mighty push or slow the chair back down then push to accelerate.

    It's a very powerful motor and the system is terrific. Being able to add a power-assist to my chair in seconds and take off is amazing. I still think the programming needs to change since many times I have a very hard time making the system engage and sometimes, as I said, it seems to think it needs to speed up and I am now going faster than I want. That said, the SmartDrive has changed my life, giving me back so much. For me it's been a miracle. Good luck and I think it will get easier for you with practice.

    Quote Originally Posted by sledgrl View Post
    I just got my SmartDrive and already am having issues with the buttons. my feet have stopped my several times when I couldn't get the chair stopped in time and drove right into a closed door.

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