UPDATE: 23/05/15 - I did a teardown on another telematics box, check out post #8 for teardown number two.
Remember when I said:
... while referring to an insurance policy with a telematics box, well that policy is over so naturally I took a peek inside.
So here's "the box" and a hardwired accelerometer or some such device.
Nothing particularly interesting on the back, just a port for power.
The insides: (IMEI number covered up)
The other side of the board:
NiMH battery:
Accelerometer, I don't know what's inside, it's completely potted and I don't want to take it apart, it may come in handy for a future project.
That's all, no surprises really.
Observations:
- ARM9 microcontroller with onchip receiver for various satellite navigation systems, e.g. GPS. Chip by ST.
- 2Mb SRAM by ISSI.
- 16MB? flash by Spansion.
- Off-the-shelf GSM module by Telit.
- SIM chip is flat packaged and soldered directly to mainboard, appears the GSM service is with Telenor, there are also jumpers for Vodaphone and Tim.
- All antennas are printed on the mainboard.
- Everything except for a single connector is SMD.
- Multi-layer PCB (4 layer?).
- Nicely assembled, it's not as rugged as I thought it could be but that's to be expected, considering these things are semi-disposable and are built to a tight budget.
- NiMH battery used instead of lithium to save on cost? Since size and weight isn't important.
One last note, even though my new insurance company (also telematics) is with the same group as my last one, they couldn't reuse the box so a new one was fitted. The new box looks similar but is a different model, unfortunately there's no chance of having a closer look for the time being, I don't want to the box to inadvertently "detect" that the car has lost power, rolled several times and has gained 8m of elevation.