Surprisingly, nobody got the right answer on this one. To be honest, I wouldn’t have gotten it either, but then again there are a lot of ware-sharpshooters out there who seem to headshot my wares within minutes of posting.

Here is the cover for the unit, I think it says it all:

SRS is for a Supplemental Restraint System–e.g., an airbag–and even though it says “Diagnostic Unit” I am informed that this is the sensor and trigger controller for an airbag unit that had deployed in an accident. It’s unclear if the sensor was destroyed as part of the deployment or not, but it was removed by the mechanic who was working on the car. I haven’t seen the sensor myself, but I’m guessing it’s some kind of accelerometer assembly, and I have heard many airbag sensor assemblies are fire-once (and of course, the airbag and it’s charge are fire-once as well). Why such a unit takes so much electronics, I don’t know…maybe someone out there knows the reason??

As for picking a winner, this time it’s tough. A lot of people gave really detailed, excellent answers. I’ll have to give it this time to JimmyJo, partially because he went so far as to check with OnSemi reps for the part number lookup, and partially because I’ve already named Mouser and Roastbeef as winners in the past already (did you guys get your prizes yet…? I think I mailed them out).

Oh yes, and the crud on the board…it seems to be the remnants of some kind of foam filling that was applied to the backside of the board (possibly as a shockmount?). It’s a fairly brittle foam that breaks up into small particles when you mush it under your finger.

This entry was posted on Wednesday, March 1st, 2006 at 2:08 am and is filed under Hacking. You can follow any responses to this entry through the RSS 2.0 feed. Both comments and pings are currently closed.