Wheelchair lift for my mother

hey guys!!

i bought a wheelchair lift to transport my mother. i have upgraded the motors and the stock controls didnt work for what we needed. im trying to automate the deploy and retraction of the lift. im having trouble with the buttons....i thought i followed the button example just reworked it a little bit. i have a 10k resistor for each button. The buttons with be in the front center console of the van 20-25' away from the arduino. im using double shielded cat5e. when i put together the first button it read 10k on the money...the 2nd read 5k and so on....each decreasing. clearly i have something wrong....i have a few projects under my belt but this one will be the most ambitious one yet, i still have a lot to learn and its all been the trial and error and no formal training. each button will handle a different function of the lift (verticle deploy, verticle retract, horizontal deploy, horizontal retract, and abort). this is a close to a wiring diagram that i could come up with....if you have any questions please let me know.....if you are willing to colaborate with me that would be greatly appreciated!!

Get rid of the resistors, wire the buttons so they connect a pin to Gnd when pressed.
In the code, turn on the internal pullups, and look for a LOW when pressed.

byte button1 = 2;
byte state1;
void setup(){
pinMode (button1, INPUT_PULLUP);
}
void loop(){
  state1 = digitalRead (button1);
  if (state1 == 0){
    delay(20); // simple (dumb) debounce
    // button1 was pressed, do something
  }
  else {
  // button1 is released, do whatever that requires - maybe nothing
  }
}

What happen if it fails? Have you added fail safe measures. Is this in a vehicle, if so you need to do a lot of research on vehicle electronics such as load dump, reverse battery, etc. Just what does the arduino do? Something to think about:
Wheelchair vans with handicap lifts are equipped with a safety lift interlock. Wheelchair lift safety interlocks are designed to prevent operation of the wheelchair van or wheelchair lift in unsafe situations. For example, if the wheelchair lift is in operation, the wheelchair accessible van cannot shift into “drive.” And if you were to accidentally try to go down the road with your lift out or if a wheelchair were to come too close to the open doorway of the wheelchair van when the wheelchair lift is not at vehicle level, an alarm will sound to warn the wheelchair user. The alarm would prevent an individual from falling out of the wheelchair van. These wheelchair lift interlocks—and their functionality—are mandated by NHTSA.

Hi,

i bought a wheelchair lift to transport my mother.
i have upgraded the motors and the stock controls didnt work for what we needed.

im trying to automate the deploy and retraction of the lift.
im having trouble with the buttons....i thought i followed the button example just reworked it a little bit.
i have a 10k resistor for each button. The buttons with be in the front center console of the van 20-25' away from the arduino. im using double shielded cat5e.
when i put together the first button it read 10k on the money...the 2nd read 5k and so on....each decreasing.
clearly i have something wrong....i have a few projects under my belt but this one will be the most ambitious one yet,

i still have a lot to learn and its all been the trial and error and no formal training. each button will handle a different function of the lift (verticle deploy, verticle retract, horizontal deploy, horizontal retract, and abort).

this is a close to a wiring diagram that i could come up with....if you have any questions please let me know.....if you are willing to colaborate with me that would be greatly appreciated!!

Sorry but it can be read a lot easier.
Place the controls on a hand held control pendant at the back of the van where the lift is.
Don't automate the device.
Place an emergency stop button where it can be easily operated, two buttons if necessary.
Never operate the lift, especially if someone is on it remotely.

What happen if it fails?
Have you added fail safe measures. Is this in a vehicle, if so you need to do a lot of research on vehicle electronics such as load dump, reverse battery, etc. Just what does the arduino do?
Something to think about:
Wheelchair vans with handicap lifts are equipped with a safety lift interlock.
Wheelchair lift safety interlocks are designed to prevent operation of the wheelchair van or wheelchair lift in unsafe situations.

For example, if the wheelchair lift is in operation, the wheelchair accessible van cannot shift into "drive."
And if you were to accidentally try to go down the road with your lift out or if a wheelchair were to come too close to the open doorway of the wheelchair van when the wheelchair lift is not at vehicle level, an alarm will sound to warn the wheelchair user.
The alarm would prevent an individual from falling out of the wheelchair van. These wheelchair lift interlocks--and their functionality--are mandated by NHTSA.

Sorry, ditto.

Tom... :slight_smile:

as for using buttons, the resistors are on the wrong side.
they do nothing for the pin side of the switches.
put them on the pin side to pull down when the button is not depressed.

=====================

as for modifying a device, it is often best is you can use the original device and just push the existing buttons.
that keeps in all the safety feature and such.

as you are aware, we are very worried that you want to work with a device that has more than enough power to move a human body, and that has options like retract, possibly fail and hurt someone.

as a group we would say, HIRE A PROFESSIONAL

For any long distance digital use opto isolators , pull up resistors are insufficient .
Agree with the others safety is paramount - any stop system should be hard wired outside of the Arduino , limit switches should also be direct acting .

i have a a voltage regulator powering everything.....i have an abort setup as well.....im using a nano that the abort switches are connected to and when triggered the nano with send LOW to the reset pin on the Mega

hammy:
For any long distance digital use opto isolators , pull up resistors are insufficient .
Agree with the others safety is paramount - any stop system should be hard wired outside of the Arduino , limit switches should also be direct acting .

i have limit switches at all of the limits of travel.....the abort system is external as well....i have a nano with the abort switched connected....when triggered the nano send LOW to the mega's reset pin....stops it cold....as for opto isolators, how do they work? i never looked into them do i need one for each button?...would that eliminate a resistor?

gilshultz:
What happen if it fails? Have you added fail safe measures. Is this in a vehicle, if so you need to do a lot of research on vehicle electronics such as load dump, reverse battery, etc. Just what does the arduino do? Something to think about:
Wheelchair vans with handicap lifts are equipped with a safety lift interlock. Wheelchair lift safety interlocks are designed to prevent operation of the wheelchair van or wheelchair lift in unsafe situations. For example, if the wheelchair lift is in operation, the wheelchair accessible van cannot shift into “drive.” And if you were to accidentally try to go down the road with your lift out or if a wheelchair were to come too close to the open doorway of the wheelchair van when the wheelchair lift is not at vehicle level, an alarm will sound to warn the wheelchair user. The alarm would prevent an individual from falling out of the wheelchair van. These wheelchair lift interlocks—and their functionality—are mandated by NHTSA.

i have limit switches, and external abort system. the lift isnt one that she would "ride on"...she drives on to the platform and then waiks to the drivers seat, then retracts the lift.

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