Device that senses motion and calls the house phone


I was referred to Arduino by a friend on another forum and I want to see if you all think my project is possible.

I'm trying to detect whether or not a person passes though a hallway (or doorway) in a specific window of time (to be read from the computer's internal clock... or ?) and if not trigger an alarm. There will be two 20-minute windows of time each night and the environment may be well lit, dimly lit with a night light, or dark. That's a quick summary of the idea.

Other things I would like to implement: 1) A disable/resume button for people to pass through and avoid false positives (10 minute window? maybe, maybe not...) 2) Have the computer call the house it's being used at for the alarm

On my list so far: 1) Arduino Uno 2) Motion Sensor: - reports of it not working well on 5V? What about use in low light?

I found a cellular shield here but it puts me over-budget: Is there a way Arduino could make Skype calls or interface with a modified $20 pay-as-u-go phone?

Thanks in advance,


This sounds very do-able. The way I see it, there are two things you will need to be able to aquire: ---a number pad phone (landline phone) ---the pir sensor

You can use the PIR sensor to sense movement in the doorway and report it to (for example) pin 8. then hack the phone's switch. Remove the switch and put a transistor in its place. that way we can control whether or not the phone is off the hook. Once we have control of whether the phone is off the hook or not, we will have the arduino generate the two tones. (see the chart in the link bleow) Telephone frequencies sound odd because they are not individual tones. They are the combination of two seperate ones! I believe that creating the two diferent tones could be done by wiring pin 9 and 10 directly together and have them output the desired tones if pin 9 generates one frequency and pin 10 generates another, it would sound just like a phone.

This would call a number if the phoneline was not off the hook. Once the call is placed, you would program the arduino to wait about three seconds, and then play the melody of a song or something!

I hope this helps!

I made a telephone dialer interface for the Arduino. Another way to go is to interface the Arduino to a serial modem.

Great thread. I think the trick here would be placing an outgoing call on the land line to the same (originating) number. IOW, calling yourself. I know it is possible in some locales but it depends upon the carrier, etc. Usually they only allows a ring back with no voice message. The alternatives are more expensive - 1) use cell technology to dial the number 2) purchase a second land line. Skype might be an alternative as well but much more complex to drive from an Arduino. Perhaps the Arduino would talk to a PC or similar to facilitate the communication?


If the phone route doesn't work, you can have the arduino send you an SMS text message to your cellphone

All you need it to do when it detects motion is to send an email Most carriers use email to SMS gateway like this If I send an email to, it will send a text to that number Here is a list with many providers and their gateways

And you can use something like GoBetwino to send emails

If you are in the United States there are rules (laws) about attaching things to the telephone lines. Just a thought