Development of a GPS tracker from scratch and 512 months guarantee

Welcome! For more than five years engaged in the development of various devices to monitor vehicles, this article will tell you about the whole process, from concept and development boards to the final stage of production in repetitive batches. Anyone interested – please tackle (lot of pictures).

Development

We are one of those who does everything themselves. Let the long, albeit expensive, but in such cases, we remove all defects before release, and to blame in case of failure, no need. The main problem that stood in the development of a new device – the reliability, the availability of accelerometer, work with any device via rs-232 as well as the convenience and ease of installation for the end user (bought – put – use). Any electricians and other installers.

GSM

due to disruptions in the supply of Telita in Ukraine, the choice was made in favor of the module Quectel M12. The module is quite famous and has replaced the module M10. It has the same form factor as Calves (SMT), easy to Troubleshooting, because all its output displayed on the sides (no BGA). For the most part, the module has exactly the same (or very similar) characteristics to Telito. It is worth noting that in the market of Ukraine almost all the modules have the same functionality with the major differences only in the environment of the development, and then everyone chooses what he knows best and what is comfortable "to write." I want to mention about the chip M12 in the form of OpenCPU, which highly reduces the entire development process ready device, and extremely easy to learn.

GPS

Well, there's actually an interesting story. Initially, it was developed under the chip used last device . 625r. But at the time of ordering the Chinese said that this chip is discontinued, and they are 100% sure that the new chip (their own production) will satisfy us a little less than full. In the process of negotiations was agreed upon pin-to-pin compatibility (which is rx,tx,reset (here special attention, this will be written below), land), this point was repeatedly raised in the correspondence and oral negotiations. Extremely happy with the new Sirf IV and support download the ephemeris for work mode a-gps. Looking ahead, I can say that if you remove a fairly large number of defects (about 10%, which is the glory of God, it is possible to weed out at the stage of assembling the devices) the quality of the receiver is quite excellent.

Build the number zero

Because poison for such a device is not very convenient, it was decided to use a breadboard for initial revision


Here's a "perfect" trace:


A little snafu in the development:


Well, the main employees of the closeup:


After debugging all the key moments went to the human layout and preparation for production. The result below (both sides for comparison):


After all the specs of the fee was given to the production and 8 weeks for the manufacture of the first batch were spent on the search / purchase of all spare parts. About two months later, the first 10 devices:

As usual

After receiving the first samples, usually the fun begins is when everything seems right and seems to be tested for a long time, and nothing works. Or working, but not. Just not running and already like anything and cannot be modified.

performance characteristics of the finished device

— start for 2 seconds, AGPS
— sirf IV (the possibility of adding glonass to the Russian Federation variants)
the memory for 250,000 points
— adaptive mode
— shock sensor / vibration (accelerometer)
mode beacon
— remote monitoring and control of tariff plans through direct USSD commands
— work without a server by SMS
— and many more, details here

Bonus

Retail cost of the device at the moment is 180.e. Dealer prices at some level to fall to 110.e. On our service, the subscription fee until the end of 2013 is completely absent when you connect any number of devices.
As usual, the warranty on 512 months from the date of purchase (battery not included).

Article based on information from habrahabr.ru