duckredbeard
Posts: 46
Joined: Mon Apr 29, 2019 1:53 am

Use 3.8VAC as input

Mon May 20, 2019 1:47 pm

My garage door has a rpm sensor that puts out about 3.8VAC when the door is running. I want to capture when that starts and stops. I don't need to know the RPM info, just that it is in a "running" state.

When it starts running, do requests.post to URL.
When it stops running, do requests.post to URL.

These URLs are Join URLs that initiate tasks on my phone to indicate what is happening with the door.

I compel thee to opine.
You can't know your limits until you exceed them.

hippy
Posts: 5790
Joined: Fri Sep 09, 2011 10:34 pm
Location: UK

Re: Use 3.8VAC as input

Mon May 20, 2019 2:10 pm

Rectifying and smoothing the AC, driving an opto-isolator, would be my first suggestion -

Code: Select all

                 ___   .---------------.
  O---|>|---.---|___|--|----.       .--|---( GPIOx
          __|__        |   _|_   | /   |
AC In     ==.==        |  _\ /_  |<    |
            |          |    |    | \   |
  O---------^----------|----'       `--|---( 0V
                       `---------------'
A full-bridge rectifier may be a better, even easier, solution. And you don't need the rectifying diode or smoothing cap if your software can handle the input briefly being de-asserted while the AC is present.

Brandon92
Posts: 773
Joined: Wed Jul 25, 2018 9:29 pm
Location: Netherlands

Re: Use 3.8VAC as input

Mon May 20, 2019 3:01 pm

How do you know this is a 3.8VAC signal. I would think the signal is more "digital".
Also, how much can you load that sensor. If you load it to much with your sensor, the output could be something different than you would expect.

duckredbeard
Posts: 46
Joined: Mon Apr 29, 2019 1:53 am

Re: Use 3.8VAC as input

Mon May 20, 2019 4:25 pm

I will check AC or DC again tonight. I used a Fluke 87 on the orange wire in the diagram found in the pdf of this link:
https://store.geniecompany.com/collecti ... 000/wiring

The opener users this sensor to confirm that the door is running. When I disconnect it, the door only moves 1 inch. Probably to safeguard against the motor trying to move a jammed door, which would overload the motor.
You can't know your limits until you exceed them.

Brandon92
Posts: 773
Joined: Wed Jul 25, 2018 9:29 pm
Location: Netherlands

Re: Use 3.8VAC as input

Mon May 20, 2019 5:14 pm

duckredbeard wrote: I will check AC or DC again tonight. I used a Fluke 87 on the orange wire in the diagram found in the pdf of this link:
With that meter you can also measure the frequency/ duty-cycle? of that signal. This will give you al lot of information about that sensor in your case.

duckredbeard
Posts: 46
Joined: Mon Apr 29, 2019 1:53 am

Re: Use 3.8VAC as input

Mon May 20, 2019 8:01 pm

Confirmed 3.5VAC at 233hz (+/- 3hz). Would be sweet if I could use that as an input.
You can't know your limits until you exceed them.

Brandon92
Posts: 773
Joined: Wed Jul 25, 2018 9:29 pm
Location: Netherlands

Re: Use 3.8VAC as input

Mon May 20, 2019 8:09 pm

duckredbeard wrote:
Mon May 20, 2019 8:01 pm
Confirmed 3.5VAC at 233hz (+/- 3hz). Would be sweet if I could use that as an input.
Ehm, is it possible that you make a picture of that sensor. Is the input, (power supply) of that sensor DC?

Edit:
When I take a look at the manual what you provided. I'm almost cirtain that that signal is DC (PWM). And you measure a AC value, because of the nature of that signal. This is also comfirmed by the following parts in the manual: wiring diagram (vcc, signal, geen), Opto Wheel and Opto-Luctor Assembly. What suggest that is a sensor like this.

duckredbeard
Posts: 46
Joined: Mon Apr 29, 2019 1:53 am

Re: Use 3.8VAC as input

Tue May 21, 2019 1:08 pm

Brandon92 wrote:
Mon May 20, 2019 8:09 pm
duckredbeard wrote:
Mon May 20, 2019 8:01 pm
Confirmed 3.5VAC at 233hz (+/- 3hz). Would be sweet if I could use that as an input.
Ehm, is it possible that you make a picture of that sensor. Is the input, (power supply) of that sensor DC?
Input is about 11VDC. Linky for the part: https://store.geniecompany.com/collecti ... pto-luctor
You can't know your limits until you exceed them.

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