Cypres 1 turnoff problem, I finally caught one

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Note: This discussion does not refer to the Cypres 2.

Much has been said about the inability to turn off the original Cypres. Many people have experienced this. The characteristic I have seen is that when the switch is activated, the LED does not even come on the first time. In other words, it is not "seeing" the switch.

I have been unable to turn off a Student Cypres during descent, and until now thought that this was a problem only with the Student Cypres or when the unit is busy during altitude calculations during descent.

I finally caught a unit doing it on the ground. (I have heard that other people have had problems with them on the ground.) This unit is in an experienced jumper's rig, which was being borrowed by a jumper with 30 or so jumps, and this jumper asked me what was going on when he was unable to turn it off.

I verified (multiple times) that the LED would not come on in response to a switch operation.

I then remembered people talking about getting a response from the unit by rapidly pushing the switch numerous times. I tried this and it worked.

For the many of you claiming over the years that it is a "user" issue, e. g., not knowing how to operate the switch, well, sorry, it ain't true.

[virgin-burner 1]

lended a rig recently, and had the same problem; turned out the battery needed replacement, it worked well after that!

i have the impression the cypres2 is a far better product, based on that observation..

“Some may never live, but the crazy never die.”
-Hunter S. Thompson
"No. Try not. Do... or do not. There is no try."
-Yoda

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lended a rig recently, and had the same problem; turned out the battery needed replacement, it worked well after that!

I will check into that with this particular unit.

[tetra316 0]

Haven't heard of this problem nor have I any problems turning mine off. I always turn it off when leaving the dz as i live an hour away through the hills. Interesting.

[Nutz 0]

You know, you can't drive down a hill fast enough to set it off - theoretically. It takes more power to turn it off than it does to just leave it on and let it turn itself off. (At least that is what I have heard. )

"Don't! Get! Eliminated!"

[kmills0705 0]

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You know, you can't drive down a hill fast enough to set it off - theoretically. It takes more power to turn it off than it does to just leave it on and let it turn itself off. (At least that is what I have heard. )

I have an original Cypres and have never had the problem of turning it off.

Kim Mills
USPA D21696
Tandem I, AFF I and Static Line I

[tetra316 0]

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You know, you can't drive down a hill fast enough to set it off - theoretically. It takes more power to turn it off than it does to just leave it on and let it turn itself off. (At least that is what I have heard. )

It's not setting it off that I turn it off for, it's the battery usage. It takes more battery power for it to recalibrate itself for the altitude changes for an hour then it does to simply turn off the unit. So therefore by turning it off I'm using less battery power than leaving it on and driving home.


At least that's why I do it, but I can't recall where this info came from. Hopefully, it's accurate though.

[BrianM 1]

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It takes more power to turn it off than it does to just leave it on and let it turn itself off. (At least that is what I have heard. )

I've heard this a lot of times. As an engineer with a background in embedded systems, I've always been skeptical. Google found CYPRES current draw measurements: http://www.pcprg.com/cyprespc.htm

Average current draw in standby:
(27 s * .23 mA + 3 s * 6.5 mA) / 30 s = 0.857 mA

While turning off, assuming LED flash and button pushes are 1 second long (they are actually shorter than that, so it will actually use less charge than this, but close enough for our purposes):
3 s * (7.6 mA + 13.5 mA) = 63.3 mA*s

So turning off is equivalent to being in standby for 63.3 mA*s / 0.857 mA = 73.9 seconds. Probably less since I've overestimated the duration of the LED flashes and button presses.

Conclusion: turning a CYPRES off uses less power than leaving it on, unless it is within about a minute of turning itself off.

"It's amazing what you can learn while you're not talking." - Skydivesg

[captain1976 0]

I had the problem with my Cypres 1 after it sat for a couple of years. The light would come on occasionally when I pushed the button. Then I couldn't turn it off once calibrated. I would just wait for it to turn itself off. Then it started working OK on its own. I have since changed the battery and haven't had any issues.

You live more in the few minutes of skydiving than many people live in their lifetime

[jurgencamps 0]

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It takes more power to turn it off than it does to just leave it on and let it turn itself off. (At least that is what I have heard. )

I've heard this a lot of times. As an engineer with a background in embedded systems, I've always been skeptical. Google found CYPRES current draw measurements: http://www.pcprg.com/cyprespc.htm

Average current draw in standby:
(27 s * .23 mA + 3 s * 6.5 mA) / 30 s = 0.857 mA

While turning off, assuming LED flash and button pushes are 1 second long (they are actually shorter than that, so it will actually use less charge than this, but close enough for our purposes):
3 s * (7.6 mA + 13.5 mA) = 63.3 mA*s

So turning off is equivalent to being in standby for 63.3 mA*s / 0.857 mA = 73.9 seconds. Probably less since I've overestimated the duration of the LED flashes and button presses.

Conclusion: turning a CYPRES off uses less power than leaving it on, unless it is within about a minute of turning itself off.

Airtech gave that message to prevent that people would switch their cypres on and off between two jumps in order to save some batteries.

It's more than probable that it's the switching on that costs a lot of energy.

[Nutz 0]

I knew that would get a lot of replies.

"Don't! Get! Eliminated!"

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.... Then I couldn't turn it off once calibrated. I would just wait for it to turn itself off. Then it started working OK on its own. I have since changed the battery and haven't had any issues.

OK, now we are starting to get somewhere. I asked the owner of the unit I caught not turning off, and he said it was getting near the end of the battery life.

If anyone else has had similar experiences please tell us.

[piisfish 135]

does the battery have over 500 jumps or 2 years ?

is the tension of the battery acceptable (within limits fixed by manufacturer, and displayed while turning the Cypres on) ?

is it an equipment failure or an operator failure ?

scissors beat paper, paper beat rock, rock beat wingsuit - KarlM

[Gary73 8]

When an AAD is sitting at the DZ, it checks altitude about once a second. Once it detects a change, it assumes that it's in a jump plane and starts checking altitude about thirty times a second. That significantly increases battery drain. If a rig is going to stay at the DZ at the end of the day, leave it on. If it's going to leave the DZ, turn it off first, especially if there are any elevation changes between the DZ and home.

Hadn't heard that "push the button frequently" approach for a CYPRES that won't turn off. I'll give that a try next time. Thanks!

"Extraordinary claims require extraordinary evidence." - Carl Sagan

[tetra316 0]

Although I've never had a problem turning off mine, I have heard several people complain about theirs. In every instance I was able to turn it off myself. Seems they are simply pressing the button too hard and too long and that is why it was not activating the shut down mode. Light and short and it works

[BrianM 1]

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Airtech gave that message to prevent that people would switch their cypres on and off between two jumps in order to save some batteries.

It's more than probable that it's the switching on that costs a lot of energy.

If you're going to turn it off and immediately turn it back on, then sure, of course it does. If you're going to leave it off for more than a few minutes, you'll still save power by shutting it off in between - not that I'm recommending it. The point I was reply to was the question of turning it off versus letting it shut itself off - it wasn't about power cycling between jumps.

In any case, as a rigger I've never had to replace a CYPRES battery before it reached the 2 years/500 jumps limit, and I jump at a DZ where we land off the airport, so AAD's get power cycled after every jump. I really don't think it matters in practice, with perhaps the exception of the case where it will detect a "takeoff" on the drive home.

"It's amazing what you can learn while you're not talking." - Skydivesg

[tetra316 0]

I've had two replace my cypres battery before two years but less than 500 jumps before. It was when I was jumping 4-6 days a week and alternating between tandems and camera. Just turning it on that many times a week was enough to drain the battery faster.

[hackish 8]

If you are concerned about the unit having enough juice to flash the LED so you can turn it off then how the heck will it ever have enough juice to charge the cap used to fire the cutter in the event of a firing? Instead I would be leaning more toward a cable failure.

-Michael

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If you are concerned about the unit having enough juice to flash the LED so you can turn it off then how the heck will it ever have enough juice to charge the cap used to fire the cutter in the event of a firing? Instead I would be leaning more toward a cable failure.

Michael, I'm not concerned about a particular unit. I'm trying to find the reason that many original Cypres units sometimes will not turn off. The reason most often given is that the user is not activating the switch correctly. But there are many people who have experienced this problem that know quite well how to operate the unit. By the way, a cable failure is a reasonable possibility too.

[hackish 8]

Do not forget that case where a cypres that was turned off fired out the door of an aircraft. The advice when dealing with an AAD that won't turn on or off always should be to have it removed and inspected before jumping it again.

I too saw a cypres that wouldn't turn off at the end of the day last year at a boogie. I also tried a trick someone on this forum mentioned where you take two AAD's side by side and press the buttons at the same time which would presumably work if the LED was inoperative for some reason (bad solder joint or bad wire). It didn't work in this case.

I'm sure if there were as many (competing brand) out in the field you'd probably find some sort of consistant failure on those too. I would be interested to hear the official report from airtec.

-Michael