EEVblog #1165 - Cypres Parachute Safety AAD Teardown

[EEVblog]

DejaVu. Dave revisits the new generation Cypres 2 parachute Automatic Activation Device and tears it down.
A safety device that automatically activates your parachute at a pre-set altitude. It has saved over 4000 lives to date.

[station240]

Dave, the little board with the two SOT23's on it, also has some sort of 3 pin thru hole part.
Could pry it out to see what that is.

Also having found the lithium cell was dead, why did you not apply a bench supply to see if it powers up ?

[cnxunuo]

The plastic is the cartridge wall, which holds the wedge shaped slug in place, heres an 300Kv xray of before and after

[cnxunuo]

from left to right,
electric wire with some lead based primer charge wrap as a ball, hense the high density.
copper cased primary charge, ruptured in the top
wedge slug with shock absorbing.
I have tried some salvaged from E-waste, it cuts thru steel wire like butter. There's a bigger handheld version which uses real 9mm cartridge without projectile, can do 16mm steel bar in one shot (handheld)

[max_torque]

When ever i see "life rated" i'm always amazed at what a bodge the devices actually look!  Loads of iffy soldered flying leads, bodge components etc.......

[Chipguy]

This transparent gel can be bought in 2x 1 kg glass bottles, it's a two component stuff that is pretty expensive. It has a shelf life of only 6 months.
After that the gel becomes unstable and does not fully "dry" and will still flow around.
Somebody wants some? 

It's no problem to use it with the pressure sensor, it transfers the pressure in a very very linear way.
In fact it is so linear that Fluke uses that in their type 713 pressure calibrators. They use a NovaSensor NPC1210 with that gel inside to make it moisture resistant.

I have made some experiments with that gel for pressure sensors as well, and used Merit M12 series sensors.
They are also available with that gel inside the chimney, but with black dye.
Reason is that pressure sensors are also light sensitive and the gel then blocks the light.
It does not matter in the Cypres Product since there is no light inside.

[Kleinstein]

It looks like the pressure sensor went out with the gel. At least the chip is gone at the end.

I was expecting some labels outside to show it being not RoHs. As least aviation electronics can still require (not just allow) leaded solder.

[johnlsenchak]

Why would   somebody  be   a  "Melf" resistor / diode  fanboy, that's just strange  in my  opinion 


Anyway,  Dave    how  come you didn't connect  the bench  power  supply  to the device directly in place of the battery  to  see if  it powered  on?

That might  have made  the video a little more interesting , just say'in

[LapTop006]

Why would   somebody  be   a  "Melf" resistor / diode  fanboy, that's just strange  in my  opinion 

I've heard claims that they're still better at specific things (stability or RF? can't remember).

Either way Stanford Research's (SRS) design department do seem to be members of that club.

[Chipguy]

I've heard claims that they're still better at specific things (stability or RF? can't remember).

Either way Stanford Research's (SRS) design department do seem to be members of that club.

At one time that really was the case. They used to have less aging and especially a lower tempco than chip resistors.
They also were better in terms of high current pulses.

But since around 2003 this has changed and precision / rugged resistors are more available in chip casings.

[mcovington]

Everybody who makes CPAP machines needs to see this video.  Notoriously, CPAP machines get water in their pressure sensors whenever anybody tilts the machine the wrong way and empties the water canister into the air tubing.  Beyond economic repair ($$).  Why can't they just use that gel?