Standalone Phone Call from Arduino-based Project

Projects General Guidance
1

Hi All,

I'm looking to determine the feasibility/difficulty of the following project:

I'd essentially like to hack an old phone to have one button on it that calls one phone number (internationally, might I add). The phone would have to be standalone (external power supply is okay). I know that it is possible to call another phone with the following shield: http://www.cooking-hacks.com/index.php/shop/arduino/arduino-gprs-module.html

However, with this project, I would like the phone to still function in that speaking in the receiver actually works and the speaker/receiver still work as originally devised. In a nutshell, it'll be a phone that can only call and talk to one number—no other numbers can be dialed.

Any input would be great.

Thanks!

2

I don't know what you want to use this for, but assuming it is for a child that you don't want calling other people than your home phone, you might want to consider widening the scope of the project to add a second button to call the local emergency services (911 in the USA), just in case something happens. Maybe just a few numbers instead of just 1 (home, cell, emergency).

While it isn't Arduino programming, I recall that several of the phones I've owned in the past have had a parental lock down setting, where the phone would only allow dialing to numbers in the contact list, and you would need a password to unlock the phone to unlimited dialing.

3

You could install a (cheap) modem inside a phone box, than dial a number using AT commands

4

Clearly, he's making a BatPhone.

batphone.jpeg
batphone.jpeg450×531 61.7 KB

5

Is your phone going to be a cell phone, or a land line?

If it's a land line, you could use loop-disconnect or DTMF to dial the outgoing call from your Arduino, and disable the phone's original dialing system. In this scheme, your Arduino would dial its programmed number as soon as it detects an off-hook condition.

If the phone is a mobile, for some mobiles you can connect via serial and dial using AT commands. I guess that would need an RS232 or USB driver, depending what type of interface your mobile supported.

6

Hah! Yes, like a bat phone.

Essentially the goal is to hack an old rotary like phone—take out the dial for a big pushdown button that would dial only one number. Since it's only one number, I figured the shield I linked to above would be easiest. I just want to make sure that the speaker/receiver functionality remains in tact. Hopefully that clarifies things a bit...