Pager Application

[chrisrust]

Has anyone managed to interface appliances with a pager? I would like to use a pager to trigger my remote car starter. The idea is to be able to use my cell phone to call my car pager and have it prompt my remote car starter to start the car. I would purchase a commercial version if one were available but I have not been able to find one. There was a model called the Smart Car Pager but unfortunately it was discontinued. I would think you could find all kinds of uses for a pager. Does anyone have any experience with interfacing with a common pager?

[gadgeteer]

That would seem easy to "fry it" with a direct wired connection. And you would need "inside information" (IE schematic) for the connection...

What kind of pager are we talking about --- maybe one that passes DTMF digits to a speaker? Perhaps a microphone (acoustic-modem-style) driving a DTMF decoder, and a PIC-chip? That way you could still receive real pages, but only a specific phone number would start the car...

[Chris Smith]

Tapping into the vibrator motor or beeper in the pager unit is the easy part, opening and solving the can of worms of starting a car is the hard part. <p>Starting cars in the cold, for example, can ruin your starter and battery, if there is no one to gage, watch, or judge the starting process.<p> How long to crank, is it started yet, grinding the starter when the motor is already running, and a whole can of potential worms? And the pager, has no feed back, or second command, should the first fail? <p>Consider the car first, and how to ensure the starting process will be done properly, and then the pager is the easy part. Do you need to pump the gas peddle, or is it fuel injected? How about the Warm up sensor, sometimes called a cranking sensor, that controls the choke like mixture? <p>A simple transistor will carry a load to turn the ignition and starter, but for how long, and how to stop it from cranking when the motor catches, and other things will keep you thinking long into the night. <p>YES, it can be done, with enough logic, but do you really want to? Sounds easy, but even the commercial models don’t tell you the whole story?

[chrisrust]

What I'm looking for is a way to trigger the remote car starter via the pager as opposed to having the pager start the car. The remote car starter already has all of the logic necessary to perform the task of starting the car. The car starter is already installed on my vehicle and it works great. My idea is to figure out a way of possibly interfacing a pager to a spare remote keychain radio transmitter. To start the car now I simply press the button on my keychain. I was thinking that if I bought a second keychain maybe I could hack into it and add some kind of circuit that would simulate me physically pressing the button. My big question is in trying to figure out how to get a pager to trigger my circuit.

[Chris Smith]

Tap off the vibrator or buzzer. Any small relay, or transistor, fet, will do?

[chessman]

I think it'd be pretty easy to have the buzzer or vibrator control a transistor. That transistor would be able to pull the remote start button either high or low....

[chrisrust]

I'm curious about how I could build the logic between the pager and my triggering circuit. The remote car starter keychain transmitter has to be held for oh, 5 or maybe 10 seconds. The car then starts. If the button is pressed again, the car shuts off. I would need some way for the pager to send a signal long enough to simulate holding the button for a few seconds.<p>My other fear is in the pager itself. My one and only pager that I've ever used (a Motorola Flex unit) had an annoying feature in which it would continue to beep after it received page until I would push a button to acknowledge. It was nothing more an alarm to let you know you had a message waiting. That feature would definitely not work with this application. <p>What would be really neat is for some way to distinguish between what you wanted to do with the page. Something like pressing 5 to start the car. If one got really elaborate maybe you could also control the power door looks.

[bodgy]

A pulse stretching circuit at the car end (ignition interface) would be what you need.<p>Colin

[frhrwa]

just about any auto toy store should have the remote start/door open/alarm system.. I had one installed on my 90 GMC 4X4.. I could hit the button and it would start up and run for up to 5 minutes... it was adjustable as to how long it turned the starter, monitored the oil pressure too.. locked or unlocked my doors, turned on/off the alarm system.. and really anything you wanted to hook up to it.. cost me about $55 around 5 years ago.. worked great .. truck was warmed up by the time I came wondering out.. and if I forgot and started another project, it shut off after "your" programmed amount of time..

[Externet]

Applications for a pager... here is a proposal:<p>A permanent always-on installation of a pager in an automobile, supplied by a separate hidden kept-recharged cell.<p>Upon reception, to trigger a valve to release a huge orange cloud of smoke and blow running fuses and horn.<p>If your car is stolen, it will be very noticed as soon as you dial the pager.<p>Just keep fingers crossed you won't get a wrong number while you travel on a freeway. (or disable it with a hidden switch) <p>Miguel

[chrisrust]

Yeah, that's great guys. I'm just looking for a way to start my car using my cell phone. I thought a pager might be the way to go for price and simplicity. Since I already have the remote car starter I thought an interface between a pager and the transmitter for the remote car starter would be the way to go. The reason I'm interested in using the cell phone is because my car sits in a company parking lot about 2 miles away. It sure would be nice to have the car warm by the time the shuttle bus arrived in the lot.

[Will]

I don't now how to do this in detail - however - What you need to dois to investigate the innards of your pager. As you and others have said, if you just hang on to the buzzer/tweeter/vibrator circuit of the pager theb any wrong number will start your car. There are two ways you can get out of this i.e. 1) Arrange the electronics so that you have to call your car twice i.e. the first time you call you will set it up so that it needs another call within, say, one or two minutes to start it OR 2) You investigate the guts of your pager and set up a circuit so that you can read and identify the phone number you leave on your pager and only act on it. You might even be able to improve upon this by ;eaving an impractical/impossible call back number on your pager e.g onr witj a letter in it or 8, followed by (say) nine 2's and ending in a 9. Have fun

[ljbeng]

I make remote monitor and control systems that use a digital cellular phone and I can turn relays on or off and monitor temperature, pressure, etc.<p>The digital phone is connected to my pc board at the monitoring station and gives you voice feedback. It is somewhat custom made to the customer's needs. The voice messages are always specific to the application and the monitored inputs vary. It is cabable of reading most any digital pulse or analog input and I can switch a limited number of relays or other outputs.<p>LJB Engineering<p>None of my custom products are shown on the website.

[desterline]

I think were starting to lead Chris' thread astray, but here's my two cents.<p>A couple years ago I remember reading an article where they were using the pager network to send data to remotly located electronic signs at a ski resort (I think in Switzerland).<p>Denny

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