Hacking analog phones for VOIP

analog_phone

[Tyler] has been using Google Voice extensively for some time now, but he hasn’t quite found a microphone/speaker setup he is happy with. He tried a headset, but that just didn’t do it for him.

While browsing around at his local thrift store, he came across an old Model 500 rotary phone for just a few dollars and decided it just might do the trick. Once disassembled, he mapped out the circuitry and got busy wiring up the handset to a pair of 3.5 mm stereo plugs – one each for the earpiece and microphone.

Once everything was reassembled, he hooked it up to his computer and gave it a spin – success!

While he is happy with how the phone works at the moment, he already has plans for improving it. He is currently looking for a way to use the handset hook to disconnect calls as well as a way to implement the rotary dial for number entry. We think that hacking a Bluetooth headset would easily take care of the first part, as well as eliminate the need for any sort of wired interface to his PC. It would also make it dead simple to use with any other Bluetooth-enabled device such as a cell phone.

We’re pretty sure he is open to implementation suggestions, so let us know what you think.

Convert an old busted phone into a voice-altering prank machine

phone_mixer

Have you ever wanted to be someone else, at least over the phone? Do you dream of turning the tables on telemarketers, making them hurry to get off the line instead of you? If so, [Brad] over at LucidScience has the project for you.

A bit of a prankster at heart, he walks through the conversion of a normal telephone into a Data Access Arrangement device (DAA), allowing you to interface it with either hardware or software-based audio mixers.

The process can be completed in a relatively short time period, and doesn’t require much more than an old telephone, a handful of tools, and some miscellaneous switches and jacks. He disassembled a telephone and trimmed off all of the unnecessary circuitry while retaining most of the original functionality. Line in and out jacks were then installed in place of the handset microphone and speakers, respectively. The final result is a compact box that relays altered audio from any kind of mixing device to person at the other end of the call. Since the majority of the phone remains intact, your calls still sound natural as they pass through the phone’s existing voice filter and preamp circuitry.

Once the DAA is complete, you can use any number of effects on your voice, limited only by your audio mixer. [Brad] says he has long-time friends that don’t even recognize his voice after he has run it through his effects machine, so get started on yours before April Fool’s day arrives!

Cassette case cameraphone tripod

We see a lot of comments on shaky video asking why that person didn’t use a tripod. [Aatif Sumar] wants to use one when taking pictures and video with his phone but the threaded mounting hole you’d find in most cameras doesn’t come as a feature on smart phones. That didn’t deter him, he used an old cassette case for this phone tripod. The build started with a cheap flexible camera tripod. [Aatif] used a soldering iron to melt a hole in a plastic cassette case. We’re apprehensive about relying on the plastic’s ability to hold threads so we’re recommend epoxy to reinforce the joint. A bit more melting with the iron and he had a cradle on legs with a hole for the camera lens. It’s nothing fancy, but it also cost him next-to-nothing.

Excuse me, my pinky is ringing

We get a lot of email challenging us to hack things. Sometimes we ignore them, other times we send some words of encouragement. But this time around we thought [Tait] had really come up with a great hack; to build a Bluetooth handset into his prosthetic finger. He hasn’t done much hacking in the past and was wondering if we could put out a challenge to our readers to make this happen. After a bit of back-and-forth brainstorming he decided to take on the challenge himself and was met with great success.

Like other Bluetooth handset hacks [Tait] started with a simple ear-mounted module. He extended the volume button with a piece of plastic and placed it under the battery. A couple of wooden matchsticks space the battery just enough so that it can be squeezed to adjust the volume level. He then extended the speaker with some wire. Next, he used the Oogoo recipe from our previous post to mold a false-finger and a thumb-ring. The PCB and battery fit in the finger, which places the microphone near a hole in the pad of the plastic pinky. The thumb ring houses the speaker to finish the look. Don’t miss the photos [Tait] sent in after the break.

[Read more...]

Your mobile phone, now with 100% more RFID

More and more today, it is becoming harder to avoid having some sort of RFID tag in your wallet. [bunnie], of bunnie:studios decided to ease the clutter (and wireless interference) in his wallet by transplanting the RFID chip from one of his subway cards into his mobile phone. Rather than the tedious and possibly impossible task of yanking out the whole antenna, he instead pulled the antenna of a much more accessible wristband with an RFID chip of similar frequency instead. Nothing too technical in this hack, just a great idea and some steady handiwork. We recommend you try this out on a card you haven’t filled yet, just in case.

Twilio adds touch tone telephone control for Arduino

An Arduino with an Ethernet shield, nothing new right? Not quite, [Chris] is showing us how to use Twilio to control an Arduino via a touch tone telephone. We saw Twilio used before in a cellphone video game but this time around an audio menu system comes into play. You can make your own menus whose options will be read by the WOPR (see the demo after the break) when you call the Twilio number. This application just turns an LED on and off but once you’ve got access to the Arduino the sky’s the limit. Most immediately this is an easy implementation for all those cellphone door lock systems we’ve seen. We also envision some classic home automation such as feed the cats or turn on the lights.

[Read more...]

Lower productivity by using a rotary num pad

[Maximilian Ernestus] sent us a quick little demo that shows him using a rotary phone dial as a num pad. We’re often frustrated when notebooks and netbooks prohibit us from using our mad 10-key skills (alternate key mapping doesn’t count). This makes coding and using GnuCash undesirable on small form factor portables.

Instead of fixing the problem, [Maximilian] made it worse by interfacing a rotary phone as a num pad. An Arduino counts the pulses and feeds them to the computer via a serial connection.  From there it’s just a bit of software handling to issue a keypress.  He mentions that a future version should register as a USB keyboard. This is a great opportunity to ditch the Arduino and use the V-USB library.

Want to dig a bit deeper into this old technology? Don’t miss out on the information available from the Magic Phone hack.