Chill Your Phone For Longer Battery Life?

The first specs we look at when choosing a cellphone are the battery life numbers. We know that eventually we’re going to see performance loss, and [Dr. West] wanted to see if there’s a way to delay the inevitable. What he found is that ambient temperature affects the battery throughout its life. He set out to build a phone chiller to slow the degradation of the battery.

The research that he points to shows that at room temperature, a Lithium battery will lose 20% of its capacity each year. This seems like a dubious number so do share links to studies that state otherwise in the comments. Whether that 20% is right or not, the point is that cooling the battery will preserve it. With that in mind, [Dr. West] put together a pod that uses a peltier cooler and a heat sink to host his Blackberry while he sleeps. He figures he can reduce the capacity lost per year from 20% down to 14%. This of course comes at the expense of running that cooler every night (in addition to charging the phone when it needs it). But perhaps this solution will spark an idea that leads to a better one.

Building An Advanced Mobile Phone Service (AMPS) Base Station

Remember the early days of cellphones and carphones when they were super-bulky and all the rage? Those early handsets used analog technology for communications in a protocol called Advanced Mobile Phone Service (AMPS). As more customers flocked to wireless providers, networks were transitioned over to digital phones in order to save bandwidth. Some places still support AMPS but it has rapidly gone the way of the Dodo. But a few years back [Mark Atherton] got his hands on some old hardware, including a bag-phone and some test equipment, and set out to build a base station that can control AMPS handsets. In short, he’s creating his own analog cellphone tower. There’s a wealth of information on his page. The writeup comes out as a mix of protocol and electronic resources he scavenged across the net, as well as a work log serving as a testament to his successes and failures. He did his experiments in New Zealand, so if you’re thinking of undertaking this make sure to research your local radio regulations first.

[Thanks J]

SMS Gateway Lets You Twitter By Text Message

[GuySoft] threw together a cellphone-based SMS gateway that allows him to push text messages to Twitter. Once up and running, it can be used by multiple people, either with shared or individual Twitter accounts. At its core, this setup uses the cellphone as a tethered modem on a Linux box. The open source software package, Gammu SMSD, provides hardware hooks for phones running in modem mode. The package is already in the Ubuntu repositories but it runs cross-platform and can be downloaded from the project site. This gave [GuySoft] the ability to script a framework that checks for received SMS messages, compares the incoming phone number for a match on a saved list, then pushes the message from a confirmed number to Twitter via their API.

A web interface is used to register new numbers and associate them with Twitter accounts. On the back-end, [GuySoft’s] own Python script handles the translation of the message. You can download all of the code, and get more insight on setup from the readme file, over at the GitHub repository.

Lower Cost Arduino Cell Shield

People love putting their Arduinos in interesting and remote places. while it may be possible, it may not be practical to run out and collect data from the devices. That is where this GSM / GPRS shield comes in handy.

Based around the SIMCom SIM900 that puts this device on the lower end of the price scale, (49 Euro for the module, ~60 Euro for the module mounted on a breakout board, or around 85 greenbacks) makes this module an interesting target for anyone wanting to add cell phone connectivity to a project.

To take this a step further [Boris] whipped up a nice shield PCB for the Arduino and Arduino like footprint users to make connections between the 900’s breakout board and the Arduino layout a snap. Electrically its just wires, and a LM317.

Cellphone Charger Has A USB Port Forced Upon It

We still can’t figure out why a standard charging scheme hasn’t been developed for handheld devices (other than greed). Certainly we understand that many devices have different electrical needs as far as voltage and current are concerned, but we still long for the ability to use one charger for many different doodads. [Rupin] is trying to narrow down the number of dedicated chargers he uses by adding a USB charging port to his Nokia cellphone charger. Since the USB standard calls for regulated 5V a hack like this can often be done just by patching into the power output coming off of the voltage regulator in the plug housing of the device. [Rupin’s] charger had 5V printed on the case, but when he probed the output he found well over 8 volts. He added a 7805 linear regulator to get the stable output he needed, then cut a hole in the case to house the connector.

Since [Rupin] wants to use this as an iPod charger he couldn’t just let the two data lines float. Apple uses a specific charger verification scheme which requires some voltage dividers to get the device to start charging.

GSM Tracking Without GPS

If you use the Google Maps Mobile function then the big G knows where you are even if your phone doesn’t have a GPS module in it. So the next time you want geolocation capabilities in a project consider building around GSM functionality which can also be used for Internet connectivity. That’s exactly what this module does and luckily the hard work has already been done for you.

The method really hinges on a couple of things. First of all, any GSM capable device knows the information about the cell it is currently communicating with. Secondly, Google knows the coordinates of radio towers used in the cellular mobile network. A little bit of data sniffing on Google Maps Mobile app communications confirms how and when cell information is transferred between the device and the maps server. Take a look at this series of write-ups which go into detail about hardware, software, cell network location data, and communication protocols which Google hasn’t publicly documented. Sure you’re not going to have the accuracy we’ve come to enjoy with GPS, but this can get you pretty close.

[Thanks Boris]

Literally Turn Your Headset Into A Handset

[Rachel’s] Bluetooth glove is proving that you don’t have to be missing fingers to talk to the hand. You can see in the video after the break that, like us, she wears fingerless gloves while typing to keep the cold from causing pain in her hands (it’s so cold in here it’s like we’re [Bob Cratchit]). So why not make those gloves multitaskers?

She cracked open a small Bluetooth headset to see if it would play nicely with her fuzzy purple gloves. A bit of wire and some shrink tubing allowed for the speaker and microphone to be moved a bit further from the circuit board. Once those components had been extended she pinned everything in place to make sure it fit the bill. The components were then sewn in place and a microswitch for answering calls was repositioned in the hollow of the wearer’s palm. Now you’re free to work the day away, with all of your incoming calls already at your fingertips.

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