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How to get Mini work with a Motion detector?


#1

Experts,

I have a unused what look like a motion detector that being used in home security. i was currious if I can wire it to my mini and code it do something. do you all think it is possible? if so what should I take into account? what code components I may be able to use?

-Thanks!


#2

You can. Does it have an LED that lights us when it detects motion? If yes then just connect this LED pin to one of the FEZ inputs. I highly recommend adding a 1K resistor in series to protect FEZ.

By the way, your question is not directly related to Mini. It is general so ti is better to post general questions in the general discussion board. Only so other users can benefit from your questions.


#3

[quote]Does it have an LED that lights us when it detects motion? If yes then just connect this LED pin to one of the FEZ inputs. I highly recommend adding a 1K resistor in series to protect FEZ.
[/quote]

Yes. I think it has some source of pulse count there are jumpper to set whether count=2 or 4 to trigger an event. so I assume that once the number of pulse count reaches the setting, it will return a signal?

[quote]By the way, your question is not directly related to Mini. It is general so ti is better to post general questions in the general discussion board. Only so other users can benefit from your questions.
[/quote]

I will post in the right room next time.
Thanks!


#4

If it would have a led it would be great indeed. You could read that with fez.

I cannot see if it has a led or not, you say yes, but is this in response to Gus? :-[


#5

What you have might be a PIR motion detector. Can you give us some details about the unit? Any markings?


#6

Yes, I have seen one of those in a local hardware store and one on the internet. I was already thinking of buying one of these soon, since they seemed easy to implement.

Does it look like this?
http://www.sparkfun.com/commerce/product_info.php?products_id=8630


#7

^^That’s the motion detector I use with my projects, and probably the same one used in your unit. If you give us more details we can probably find the pinout to connect it to your FEZ.


#8

Guys,
It will be better for me to take a picture of it and post a URL for you guy to see tonight, I pulled it out from my old home security system. so not quite sure if it even has an LED. just remember it has some source of pulse count. so wait for my next post!

Thanks!


#9

Sounds good. Will be waiting. I can probably figure out what it is by looking at the PCB.


#10

Hey Guys,
Here it is: looks like it has an LED.

http://nangmoisolution.com/DSC_0001.jpg
http://nangmoisolution.com/DSC_0002.jpg

Thanks!


#11

Yikes. No markings on that that I can really tell by. What model of system did that come from?


#12

Chris,
Must be a pretty old one came with my house which built 1989, so not sure when previous owner got this security system installed.

Thanks!


#13

Now that I look at it, I’ll be that the alarm pins are on a relay, The other pins are for power in. Can you pull the wires so that the full silkscreen is visible?


#14

As far as I can see it has a LED? This would be easy.


#15

Does it say “Alarm N.C.” under the green/white wires? If so, then as Chris says, thats a relay triggered, normally closed circuit. Give it 12v DC on the red/blk, and check with a multimeter whether you have a circuit when it’s not detecting motion and when it is - NC should mean the circuit is complete when not “seeing”, and then breaks the circuit once it detects something. Check for voltage there as well, but I expect you will not see anything. Then you can wire one to 3.3v and the other to a Fez pin - put a current limiting resistor in the line if you’re going to use it more than just for testing.


#16

Like Bretty said, you might be able to hook the Alarm pins up to a multimeter on continuity mode to check to see if it does anything. If you have an O-Scope, even better. Again, it would help if there was a picture of the unit with the wires unscrewed so we could see the full silk screen.


#17

[quote]As far as I can see it has a LED? This would be easy.
[/quote] Yes it definitely has a LED.

[quote]Does it say “Alarm N.C.” under the green/white wires? If so, then as Chris says, thats a relay triggered, normally closed circuit. Give it 12v DC on the red/blk, and check with a multimeter whether you have a circuit when it’s not detecting motion and when it is - NC should mean the circuit is complete when not “seeing”, and then breaks the circuit once it detects something. Check for voltage there as well, but I expect you will not see anything. Then you can wire one to 3.3v and the other to a Fez pin - put a current limiting resistor in the line if you’re going to use it more than just for testing.
[/quote]

I think you are right it is “Alarm N.C”, Sorry for stupid question but how do you, Expert people figure out it needs 3.3v and not 12v DC or 110v AC by looking at this thing? :-). Again, I have zero background on electrical stuffs.

Thanks, Hai


#18

Educated guessing, mostly. As for the voltage, I don’t think we can tell that, unless someone were to really look at the board to see how it was put together. I seriously doubt it’s 110V DC, however.


#19

the two NC ports are essentially a switch. It doesn’t “need” anything, it’s just open or closed depending on what it “detects”. If you apply power, any power, to it then it’ll transmit that when it is closed and won’t when it does. It’s the same as pushing a push button switch, or flicking a toggle switch. If you hook that to a 9v battery and a old-tech torch bulb, it should go on and off when you detect movement. If you hook that to a 5v power source and a resistor and a LED it should go on and off as you detect movement. So that part of the circuit is “what you make of it” nothing more :slight_smile:

The 12V is the other side of the screw connectors, which is where the input power for the circuit comes. That is going to need to be 12vDC (or whatever the silkscreen shows, I think it’s 12vDC) to make the circuitry work. Get that wrong and you’ll either let the special smoke out of it and it won’t work agian, or it’ll do nothing. So that’s the only thing I see as a strict requirement.

good luck :slight_smile:


#20

Chris/Brett,
Thanks for the explanation. Sorry I did’nt know what you all refering to as Silk Screen, now I know (the cover…ok got that). I look at it, it reads

-Power input=9.5~16VCD/17mA max
-Alarm output: N.C 28VDC, 0.2 A max
-The model of this is Optex RX-40PI,

That leads to the following questions:

  1. The detector needs minimum of 9.5v to operate, the original FEZ mini kits only have 4.5v power supply, which means to use this I need a new power source that is at least 9VDC?

  2. Assuming I need to change 9VDC power source for mini, what should I take into account with existing connected hardwares like sensors, servo… if any?

  3. How do i wire this detector to Mini, like red/white go to where in mini, N.C wires go to where in Mini?

Thank You Guys!
-Hai