Adept altimeters and momentary power loss.

At the last launch, I had my Leviathan rigged with a cable-cutter and an Adept DDC22 altimeter. I watched it plunge to the ground without firing, loosening a fin. When I recovered it, the altimeter was still beeping out continuity.

Later the same day, another flier got a drogue deployment via his Adept22, but no main. Likewise, when he recovered, his altimeter was beeping out continuity.

Someone commented that Adept altimeters don't have any recovery from momentary power disconnects. That would seem to be the case, but I was wondering if anyone had any history/info to that effect?

Never, it has worked 100%.

What battery setup did you use? Type, volts and amp-hours.

Bob

Also, what type of switch did you use?

I used a standard 9V alkaline. I had the battery cable-tied to the sled (no battery holder), and the typical 9V connector stuck on top, with nothing extra to keep it on. No switch. I used a JST connector, like twisted pair, but not twisted.

The 9 volt battery will source between 3 and 5 amps. Do you know how much current the cable cutter e-match will draw? If there is no brown out protection on the dual deployment device, it could be possible to reset the altimeter if the voltage drops below some critical value.

Bob

Been using only Adept electronics since 1995 and never had an issue to this day. Batteries? Inadvertent bad wiring error?

Bat-mite said:

At the last launch, I had my Leviathan rigged with a cable-cutter and an Adept DDC22 altimeter. I watched it plunge to the ground without firing, loosening a fin. When I recovered it, the altimeter was still beeping out continuity.

Later the same day, another flier got a drogue deployment via his Adept22, but no main. Likewise, when he recovered, his altimeter was beeping out continuity.

Someone commented that Adept altimeters don't have any recovery from momentary power disconnects. That would seem to be the case, but I was wondering if anyone had any history/info to that effect?

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It's easy to prevent a momentary mechanical power disconnect, just use a good locking power connector and firmly attach the battery and wires to the sled. Zip ties work well for this. I've seen issues with 9V batteries and some of those plastic battery holders with the snaps built into them, they can flex under G-forces and cause the battery to come loose. If you're using a 9V battery, use a good quality snap connector instead.

A little bit more insidious is the issue of an ematch shorting out after firing. If it happens to the drogue you won't get the main, if it happens to the main you won't get an altitude beep-out and you'll wonder why when you recover your rocket. I've seen that happen with Q2G2's because of their design, and even with a backup capacitor it's possible for that to cause a reset on the altimeter's processor. I've gone to using the MJG Firewire ematches instead of Q2G2's because their chip-head design prevents this from happening.

I did use a snap connector, but I am not convinced of the quality. However, I should be able to wrap it with masking tape to make sure it doesn't disconnect.

I don't think I got a short on my ematch, but I will look at it.

Another question, due to things beyond my control, it sat on the pad a long time before launch. Obviously at some point it woke up, because it was beeping out continuity when I recovered. But do you think it might have woken up too late or something?

You ground tested it, right? Put the whole thing in a jar/tub with a small hole in the bottom corner (I like to use the biggest squarish transparent plastic Planter Peanut containers with the blue lids). Slowly suck the air out until the sides sag (that's about 2000 feet), then put your finger over the hole and let the air slowly seep back in (that's about 20-50 fps). The match should fire. If you have a Jolly Logic AltimeterOne, put it in Real Time mode and its display will tell you the altitude at which it fires.

I suspect you're getting voltage sags, which "brown out" the altimeter before it heats up the igniter enough to work. So the altimeter crashes, then comes back to life. You end up with a non-burnt igniter and an altimeter that acts like it's ready for launch.

If it can work on the ground, just make sure to use a new battery each time in the air to be safe. Use the batteries first in your rocket, then put them in a box for use in fire alarms, etc, later.

The altimeter has been ground tested multiple times, and flown multiple times. This is the first time I have ever had this experience where the altimeter was beeping out continuity on recovery. I would have assumed user error, but then when the other flier had the same issue with his 22, I had to scratch my head.

I've seen Adept 22's go haywire with 2 watt Rf Garmin dog trackers. Kurt

Bat-mite said:

The altimeter has been ground tested multiple times, and flown multiple times. This is the first time I have ever had this experience where the altimeter was beeping out continuity on recovery. I would have assumed user error, but then when the other flier had the same issue with his 22, I had to scratch my head.

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Like several others, I have used the Adept products without problems. I suggest that you contact Tommy Billings via the Adept web site-I'm quite sure he would discuss your issues and test out the altimeter in question. Tommy is very knowledgeable offers excellent customer service.

Fred,
KG4YGP
L2, ROSCO member

Hmmmph,

I'll say. He's a very generous person. Willing to help. Kurt

FMarvinS said:

Like several others, I have used the Adept products without problems. I suggest that you contact Tommy Billings via the Adept web site-I'm quite sure he would discuss your issues and test out the altimeter in question. Tommy is very knowledgeable offers excellent customer service.

Fred,
KG4YGP
L2, ROSCO member

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