Posts Tagged ‘gsm’

A GPS without GPS

Monday, July 11th, 2011

gsmlocalizerWow, that sounds weird. It’s actually a mini GSM-based localizer without any GPS devices attached. It’s an old device with the cheaper SimCom module SIM900.  Here is a complete working GSM localizator which is pretty cheap and small too.

As introduction, this system allows localization without directly using GPS technology; we are able to locate the desired object fairly precisely by using database availability together with the geographic position of the cells themselves. In some country the cell coordinates are not publicly known (i.e. in Italy). If so, where do we find such data? Through Google Maps… Google has been able to store billions of data regarding the location of its clients’ cell phones. But how does GSM localization work? The radio mobile network is made up of a number of adjacent radio cells, each of which is characterized by an identifier consisting of four data: a progressive number (Cell ID), a code related to the area in which that given cell is (LAC, or Local Area Code), the code of national network to which the cell belongs (MCC, an acronym for  Mobile Country Code), and finally the company code (MNC, or Mobile Network Code), which obviously identifies the phone company itself. For this reason, once a cell name and coordinates are known, and considering the maximum distance allowed between this cell and a phone  before the phone connects to a new cell, it is possible to find out, approximately, the most distant position of the phone itself. For example, if the maximum distance has been determined to be one mile, the cell phone can be within a one-mile radius. It can be deduced that the more cells are found in a given area, the more precisely one can determine where the phone is located (up to 200-350 feet). The idea of employing only a GSM device to build a remote localization system occurred to us when we realized that Google Maps Mobile, which had been conceived to allow smartphones equipped with a GPS receiver to use Google for satellite navigation, was extended to all cell phones, as long as they were able to support GPRS or UMTS data.  Naturally, this method allows but for a rough estimate: determining the precise position of the cell phone hinges on data regarding the coverage of a given cell which can only be provided by the Google server.


The circuit

Compared to traditional localizers based on GPS, this device presents many advantages, primarily because it is lighter and less bulky, has a cost lesser and greater autonomy to exercise. This means that about one battery lithium ion, such as 1 Ah, our tracker can be in operation for several days (it all depends on the number of SMS that have to do). A locator based on cellular network may answare more immediately: the GPS receiver may take several minutes to determine its position. Our tracker works battery and thus can be brought on by people who may have the need to ask help or be tracked, but also placed on board motor vehicles (without installation) or simply introduced in goods in transit. To avoid unnecessarily draining the battery, the localizator provides its position via SMS, on requesto with a simple phone call. Among the functions implemented there is the SOS: By pressing the button the localizator sends a text message asking for help, containing the coordinates of position, the sending can be done to a maximum of eight thelephone numbers. When queried or with the autoreport function, sends an SMS with the localization.To know the location of remote device must send an SMS request cell is connected and sends a request (via GPRS) to Google’s site, the latter responds with the coordinates and the figure for the precision. Everything happens in seconds.


Well, you can get hell of these stuff from link provided afterward. Design files and the firmware are included. A fun stuff to experiment with at your disposal. Mini GSM localizer without GPS at

All images are courtesy of

Brilliant SCADA System that failed

Sunday, September 19th, 2010

A friend of mine shared an article about software failures. it’s a good stuff to read, where we can avoid some mistakes that previously been made by software developers. there is a SCADA software there – some of the problems that I’ve been encountered too in my life. check this out: – a monitoring application for water supply companies. It was a complex client server application that would receive monitoring data from specialized hardware and store that data inside a SQL database. The client displays that data in different graphs, provides printable reports or sends alarm messages via SMS if a monitored value is not within its specified limits. I developed Net-Herald as a perfect fit for that specialized hardware that is provided by a local manufacturer. That way, so I hoped, I could profit from their sales leads and would find a smoother way into these water supply companies. The downside of course, was that my software would only work with their hardware. (more…)

Cell phone based car starter, another take

Wednesday, January 20th, 2010


Dave Had been working on a cell phone activated remote start for his car for a while when we posted the GSM car starter. While both do carry out the same job, we feel that there is enough good information here to share. He’s gone a pretty simple way, by connecting the vibrator motor leads to a headphone jack. He’s using that signal to then activate the remote start by setting off an extra fob. Though it is amazingly simple, this version does have an advantage. As he points out, his cell phone has several features which could be utilized to automate some of his car starts. He can set alarms as well as recurring calendar events to get his car started without his interaction. Lets just hope he doesn’t forget and let his car run too long unattended, especially if it is in a garage attached to his house.

Source: Dave Hacks

GSM Car Starter

Saturday, January 16th, 2010


It’s just starting to warm up around here but it was very cold for a long time. We’re not fond of going anywhere when it’s way below freezing but those professional hermit opportunities never panned out so we’re stuck freezing our butts off. Fed up with his frigid auto, [Aaron] installed a remote starter to warm the car up before he got to it. This didn’t help at work because of the distance from his office to the sizable parking lot is too far for the key fob’s signal to carry. He decided to make his starter work with GSM so he could start the car with a phone call.

The first attempt involved a pre-paid cell phone for $30. The problem is that anyone who called the phone would end up starting the car. After a bit of looking he found a GSM switch that just needs an activated SIM to work. When called, it reads the incoming phone number for authentication but never picks up the phone so there’s no minutes used. He cracked open an extra key-fob and wired up the lock and start buttons to the relays in the GSM switch. Bam! A phone call starts (and locks) his car.

Maybe this isn’t as hardcore as body implants but it’s a fairly clean solution. He uses the car’s 12v system to power the switch and pays $10 every three months to keep the SIM card active. There’s an underwhelming demonstration video after the break showing a cellphone call and a car starting.

Courtesy of Hack A Day

Troll 9500 Water Quality Monitoring for Remote Locations using GSM/GPRS Telemetry

Saturday, July 12th, 2008

Troll-Link1-sm.jpgRS Hydro have recently won two seperate contracts to supply anWater Quality Sonde with Remote Monitoring Telemetry Troll Link Systemd install the Troll 9500 multiparameter water quality sonde in remote locations in Wales. Two further units are being supplied as stand-alone platforms.

The clients are using the Troll 9500 XP Professional platform along with the Troll Link solar powered telemetry system with plug and play sensors including turbidity, level, temperature, conductivity and pH/ORP. One of the clients is using the Troll 9500 to provide an early warning alarm to inform the client if any of their remedial works on a dam face are having an influence on the water quality of the compensation flow from the reservoir. The other client is using 4 units to measure water quality in a Site of Special Scientific Interest (SSSI) over a period of two years.

Both clients are using RS Hydro’s FlowView platform to provide all the data on a daily basis. Should any of the alarm thresholds be exceeded, text (SMS) messages will be sent direct to the client. It is possible to view a demo of the Troll 9500 on our local river. Before you think there are errors in the conductivity readings, they are correct! The Salwarpe RIver is partly fed by Droitiwch Spa’s naturally occuring brine baths, hence at low flows, conductivity rises dramatically.

Source: RS Hydro

No need for cables with GSM door entry system

Thursday, May 29th, 2008

Urmet Domus have introduced a simple solution for when audio communication is required as part of a door entry system but where it is not possible to install cables.

Domus Cell is compatible with all major mobile networks and provides GSM connection to Sinthesi door entry panels. The default programming enables users to have the system up and running within minutes and it can provide communication through analogue PABX systems, providing all the benefits of a standard telephone system, without the cost of installing fixed lines.

Domus Cell is a particularly practical and cost effective solution for installers of automated gates and barriers although it is also ideal for site and mobile office applications as the same contact numbers can be used for each new project. Read more about this