Be careful with those Arduino GSM cards. As [James] reports, they may turn into fire starters. One person has reported a small explosion and fire already on the Arduino forums.
Now before we go any further – You may be asking yourself who the heck [James] is, and what gives him the ability to second guess the Arduino team. Well, here is [James’] blog disclaimer: “James is a Senior Technical Expert for Technology and Applications at KEMET Electronics, a capacitor manufacturer. The content of this post are his and in no way reflects opinions of his employer.”
Senior Technical Expert? That’s a good enough reason for us to believe him.
[James] states the problem is a tantalum capacitor used to decouple the GSM radio power supply from the main Arduino supply.
Tantalum capacitors are great for their low ESR properties. However, they have a well known downside of getting very hot, or even exploding when stressed. It’s not the Tantalum Anode that is burning. The Manganese Dioxide used as a cathode in some Tantalum capacitors is the culprit. Continue reading “Safety warning: Arduino GSM shield may cause fires”
If you’ve ever worried about your car getting stolen this hack can help give you some piece of mind. It’s a cellular enabled geolocation device. These things have been in use for some time, the most common brand we know of is the LoJack. That company gives you a little box to install on the vehicle and if it ever goes missing they can grab the coordinates and forward them to the authorities. This custom version builds a lot into an addon board for an EFM32 board.
The image above shows the main components of the add-on: the GPS module and the GSM modem. Along the top edge of the board is the voltage regulator circuits which aim to keep the standby power to the slightest of trickles so as not to drain the car’s battery. What you can’t see is the SIM card slot which is located on the underside.
You can find the Eagle files for the design at the link above. We’ve embedded the video description of the project after the break.
Continue reading “Roll your own LoJack clone”
We don’t blame the manufacturer of this GSM to Landline converter box for not designing the thing from the ground-up. After all, quantities of scale have made dumb-cellphones available for next to nothing. But you have to admit that it’s interesting to see a fully populated cellphone board creatively soldered into a consumer product. It would be commonplace if made in your basement rather than being sold in a store.
[Anton] was using the box to add his analog house phones to the cell network. The signal strength at home is pretty low and this box offers an external antenna for better reception. He cracked open the case expecting to see a GSM modem and was surprised to see the cellphone board. It includes a battery backup, and has been soldered directly to the cables which interface with the main PCB using some SIL connectors. Those solder joints were done by hand directly to the pins of the SIM card slot and as well as all of the other important connection points.
A few years ago, [Phang Moh] and his compatriots were asked by a client if they could make a vehicle tracking device for oil tankers all around Indonesia. The request of putting thousands of trackers on tanks of explosives was a little beyond [Phang Moh]’s capability, but he did start tinkering around with GPS and GSM on an Arduino.
Now that tinkering has finally come to fruition with [Phang]’s TraLog shield, a single Arduino shield that combines GPS tracking with a GSM and GPRS transceiver. There’s also an SD card thrown in for good measure, making this one of the best tracking and data logging shields for the Arduino.
The shield can be configured to send GPS and sensor data from devices attached to an I2C bus to remote servers, or a really cool COSM server. [Phang] is selling his TraLog for $150, a fairly good deal if you consider what this thing can do.
Seems like the perfect piece of kit for just about any tracking project, whether you want to know the location of thousands of oil tankers or just a single high altitude balloon.
Tip ‘o the hat to [Brett] for finding this one.
Cellular shields for the Arduino have been around for ages, but this is the first one we’ve seen that turns your Arduino into a proper cell phone.
The shield is based around the SIM900 GSM/GPRS radio module, and is compatible with the SIM908 GSM/GPRS module that adds a GPS receiver. Also on board this shield are a pair of 1/8″ audio jacks, perfect for connecting a microphone and headphones. Yes, you can actually make cell phone calls with your Arduino now.
The real star of this build is the new GSM Shield library. This library of code includes the methods necessary for an Arduino to function as a cell phone (answer, hang up, dial a number), but also includes a lot of improvements for TCP/IP communication.
Even though the cost of getting an Arduino communicating through a GSM or GPRS network is fairly high, we’re thinking this would be the perfect starting point for a completely open source, open hardware cell phone. A phone with the same functionality as an old Nokia brick that is also a MiFy would be an amazing piece of hardware, and would surely make for a profitable Kickstarter.