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Topic: Garage door, getting the position (Read 4 times) previous topic - next topic

bld

Did some testing with the 200 ohm I had, and it gave a pretty nice scale from 0 to 19 with a 10k pull up resistor (wont go higher than the 19 because  of it only being 200 ohm at max).

A 10k ohm trimmer (wired to gnd), with a 10k ohm pull up resistor would give the 0-1023 scale?
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arduiYES

i used to work on garage doors and so far i know, there`s a limit switch adjuster on the box.  it`s adjusted with a screwdriver.  some are physical inside the box....gears/pressure sensors.

also, perhaps you could hack a printer.  inside i`ve seen these little wheels that are read by a sensor.  you could craftily install one of those sensors and the wheel on one side of the door by the springs on top and then monitor the input from the sensor on a normal cycle and figure from there.

arduiYES

oops---looks like you already got it figured out

retrolefty

Quote
A 10k ohm trimmer (wired to gnd), with a 10k ohm pull up resistor would give the 0-1023 scale?


Half that count. A 10k pull-up and a series 0-10k pot would form a voltage divider that you yield a 0-2.5 volt range, so a 0-511 count range, no?

Lefty

bld

#49
Jun 22, 2010, 06:36 pm Last Edit: Jun 22, 2010, 06:44 pm by bld Reason: 1
Quote
i used to work on garage doors and so far i know, there`s a limit switch adjuster on the box.  it`s adjusted with a screwdriver.  some are physical inside the box....gears/pressure sensors.

also, perhaps you could hack a printer.  inside i`ve seen these little wheels that are read by a sensor.  you could craftily install one of those sensors and the wheel on one side of the door by the springs on top and then monitor the input from the sensor on a normal cycle and figure from there.

None of that inside the one I got. It is only a 24V wiper motor, just like you would find on the wipers on your car (just 24V instead of 12V). And that is then monitored by something so it will stop when the load is too high.


Quote
Half that count. A 10k pull-up and a series 0-10k pot would form a voltage divider that you yield a 0-2.5 volt range, so a 0-511 count range, no?

Lefty

ah yes, that sounds logic, but would a 20k trimmer then allow the 10k to pull it all the way up to ~510? or would that then be something around 750?

Update
Hmm, wont ever come up to 1023, as it will always pull a bit down, would need something that would go to completely disconnected... But, that much isn't needed either... 500 steps over 195cm makes it precise within 4mm. That should do it ;)
captain-slow.dk | non contagious!

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