recycle cell phone as garage door opener

I hope some genius on this usenet group can give me some clues in recycling a cell phone. I spent over a $100 for it about 5 years ago. In todays' dollars that must be $150. Sprint persuaded me last year I should get a RAZR. Maybe I'm too gullible and should still use the Moto 120, I don't know. I do know I have lots of company. Surely it could be a good walkie talkie, garage door opener, etc and not lay around wasting space in my tool box. In fact I have two! One is a Motorola V Series Dual Band Model 120c. The other is a Qualcomm QCP 1920. I've been a programmer since the days of the IBM7090, wrote some disk drivers for the IBM360 so I'm not totally stupid (at least not yet). Come to think of it, we have some old PCs wasting space too that cost a h--l of a lot more than these phones. Maybe one of them combined with a Cell can make Bill Gate's garage look like Buck Rogers?

Anybody else out there interested in Real-World interfacing with your (old) cell? (Yeah, I hear some boys over Arabia-way do some black magic with them. That is NOT what I want to do. But white magic is a horse of a different color. right?)

Reply to
Bob
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Sell it to a recycler who recodes it and ships it to some second or third world country. Its on the wrong band for a garage door opener, and you don't have the resources to convert it to to a walkie talkie, or the money to pay the FCC for its use afterwards. Why would you want to spend over 100,000 dollars to modify a 100 dollar phone?

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Service to my country? Been there, Done that, and I\'ve got my DD214 to
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Reply to
Michael A. Terrell

There are agencies that attend to the needs of battered women who have restraining orders out against their stalkers. They give out donated used (unactivated) cell phones that can still be used to call 911. Donate the unit to one of those organizations.

You *could* make a needle threader out of a crowbar, but that would be ridiculous as well.

Reply to
JeffM

Hi Mike - thank you for your reply.

I too have my DD214.

What I'm thinking is: Cheap inexpensive DIYS project to satisfy my curiosity: #1 Cell phones are small 2 way radios - receive and transmit signals at certain frequencies. They have fairly decent batteries which, after several years use, are in poor shape but they come with battery chargers and mine will operate from the charger. The price for a replacement cell batteries is high. The price is right for the charger is just right - free.

#2 A garage door opener is a primitive radio receiver connected to a comon solenoid circuit. One state turns on the electric motor to revolve in a direction that winds up the garage door. Another state is OFF. The third state runs the motor in reverse and closes the door.

So far this is about as complicated as a screwdriver. Reminds me of what I learned about early radio experiments with crystals and so on.

Then there is security. I've heard of a couple ways that is done. First we are talking very low power so the signal is weak and reception is nill beyond 50 feet or so. Our old unit has a small circuit board with a few cheap components that act in combination to tune the unit to one of several thousand possible frequencies. Johnny Q. Thief has between slim and none chance of getting into my garage unless he camps on the driveway for a weekend.

#3 When #1 and #2 are tuned to the same frequency, they can communicate, especially simple things like on and off and that is all that is necessary.

#4 Why bother? DIYS - and my current garage door > Bob wrote:

Hi Mike

I too have my DD214.

What I'm thinking is: #1 Cell phones are small radios - receive and transmit signals at certain frequencies. They have fairly decent batteries which are usually not in very good shape after several years but, the ones I have, also came with battery chargers and will operate from the charger. The price of the batteries for the cells I've looked at seems way higher than is necessary. The price is right for the chargers - free.

#2 A garage door opener is a primitive radio receiver connected to (I'm guessing) a three state solenoid. One state turns on the electric motor to revolve in a direction that winds up the garage door. Another state is OFF. The third state runs the motor in the opposite direction and closes the door. Reminds me of what I learned about early radio experiments with crystals and so on. I know that security must be provided also and I've heard of a couple ways that is done. First we are talking low power so the signal is weak and reception is nill beyond 100 feet or so. I think commercial units include a small circuit / crystal with a few cheap components that tune the unit to one of about ten thousand possible frequencies and that way the chances that John Q Thief will have little chance of getting into my garage.

#3 When #2 is tuned to a frequency used by #1, they can communicate simple things like on and off and that is all that is necessary. The reason I'm thinking about this is my current garage door opener stopped communicating with the opener (or vice versa) and I'm thinking about Doing It Myself. I'm sure you've been there and done that too. Right?

Reply to
Bob

On Fri, 05 Oct 2007 15:52:57 +0000, Bob wrote: ...

Wrong. If it's broken, get it fixed rather than trying to hack something else.

Frankly, the idea of hacking a cell phone to make it operate a garage door opener doesn't really sound quite sane.

Did you replace the battery in your hand-held?

Good Luck! Rich

Reply to
Rich Grise

They are dedicated devices that have to 'phone home' to the network to operate.

That is done by the controller on the motor. There is usually only an open circuit to initiate the next function, and new units have a second set of terminals for the safety auto reverse. I repair the receivers and transmitters for about five years, for a friend's garage door business.

A modern cell phone is NOTHING like a crystal radio. You would have a better chance of repairing the old transmitter and receiver than converting a cell phone.

A carefully tuned pair of controls will open a door a lot further than 50 feet. I have set them up to work well over a city block.

No, to a couple channels, and different digital codes.

I would use a replacement receiver, and put a vacation switch in the garage that disables it while you're gone. Then, they would have to pry the door open.

Cell phones don't transmit and receive on the same frequencies.

A replacement transmitter and receiver is under $100 and takes a half hour to install and program. Lowes, Home Depot and other DIY places sell them.

Have you looked at the chips used in a modern cell phone? A lot of them are proprietary so unless you work for the OEM at the right level, you'll never get any data. There are very few salvagable parts, You would have to write new software for the phone to keep it from calling the local cell tower when its turned on, so you could spend years and still not have a usable unit.

The old bag phones were more hackable, and turn up for a dollar or two in thrift stores and yard sales. If the phone works let someone else use it up. I worked on the test line for Telemetry radios, so I can tell you that without some idea of the design, you are wasting your time. With the production volume of any model cell phone, the software may be hard coded. Without changing that code you need the card to let it turn on. Find another item to recycle into a project. Also, most of the cell phones I've seen need special security tools to open the case.

--
Service to my country? Been there, Done that, and I\'ve got my DD214 to
prove it.
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Reply to
Michael A. Terrell

Yep. One end is the phone, the other is a cell. They can't communicate with anything other than a cell.

And those frequencies are reserved for the mobile phone companies. It's illegal to transmit on those frequencies other than as directed by the cell.

Even if it weren't for the legal issues, there is almost nothing you could salvage from a cellphone which would be of use for any other purpose. It's almost entirely custom circuitry.

Reply to
Nobody

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