Development of GPS tracker from scratch and 512 months warranty

Greetings For more than five years we have been engaged in the development of various devices for monitoring vehicles, this article will tell about the whole process - from the idea and model board to the final production stage in serial batches. Who cares - please roll up (many pictures).

Development

We are one of those who do everything themselves. Let it be a long time, albeit expensive, but in such cases we remove all the shortcomings until the moment of release, and nobody needs to blame for the failure. The main tasks that faced the development of a new device were reliability, the presence of an accelerometer, work with any devices using rs-232, and also the convenience and ease of installation for the end user (bought - installed - used). No auto electrics and other installers.

GSM

Due to interruptions in the delivery of Telita to Ukraine, the choice was made in favor of the Quectel M12 module. The module is quite famous and replaced the module M10. It has the same form factor as Telit (SMT), it is convenient in troubleshooting, because all its outputs are bounded on the sides (no BGA). For the most part, the module has absolutely the same (or very close) characteristics to Telita. It is worth noting that in the Ukrainian market almost all modules have the same functionality with the main differences only in the development environment, and here everyone already chooses what he knows best and what is more convenient to “write”. I would like to mention about the M12 chip in the form of OpenCPU , which greatly reduces the entire process of developing a ready-made device, and is extremely easy to learn.
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GPS

Well, there is an interesting story. Initially, everything was developed under the chip, which was used in the past device Uranus 625r. But at the time of the order, the Chinese stated that this chip was discontinued, and they are 100% sure that the new chip (of their production) will satisfy us a little less than completely. During the negotiations, pin-to-pin compatibility was agreed (and this is rx, tx, reset (special attention will be written about this below), the ground), this point was raised several times in correspondence and oral negotiations. The presence of a new Sirf IV and support for loading ephemeris for the a-gps mode is extremely pleased. Looking ahead, I can say that if you remove a fairly large number of defects (about 10%, which thank God, you can filter out at the device assembly stage) the quality of the receiver itself is quite excellent.

Build number zero

Since it is not very convenient to poison a board for such a device, it was decided to use a prototype board for the initial revision


This is the “perfect” tracing:


A little embarrassment in the development:


Well, the main workers in close-up:


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


After coordination of all specifications, the fee was given to production and 8 weeks for the manufacture of the first batch were spent on searching / purchasing all the spare parts. About two months later, the first 10 devices were received:

As usual

After receiving the first samples, the most interesting part usually begins - this is when everything seems to be correct, and seems to be tested for a long time, but nothing works. Or it works, but not like this. It just does not work and it seems that nothing can be changed.
So it happened. The incoming "magic" GPS modules simply "were silent." We put the old ones - everything works, we call new ones - it should work, but “the skis do not ride.” The reason is the use of reseta at the first start, when the module first accesses the stack. The Chinese, with their usual surprise, said that “they needed to be warned” and sent a manual on how to get everything back in place. After raising all the correspondence and sending them, they simply promised that this would not happen again. A curtain.

TTH of the finished device

- start in 2 seconds, AGPS
- sirf IV (the possibility of replacing options for glonass for the Russian Federation)
- memory on 250000 points
- adaptive mode
- shock / vibration sensor (accelerometer)
- lighthouse mode
- remote control and management of tariff plans through direct USSD commands
- work without a server via SMS
- and many more, described in more detail here.

Bonuses

The retail cost of the device at the moment is 180 USD Dealer prices at certain volumes fall to 110 cu On our service, the subscription fee until the end of 2013 is completely absent when connecting any number of devices.
As usual, the warranty is 512 months from the date of purchase of the device (the battery is not covered).