Troubleshooting a Raven 2

I have a Raven 2 that won't power up. I suspected a battery issue because the FIP says the Raven is not powered up. Charged all my batteries and confirmed >3.7V, but no joy. I guess they could have a loading issue, but probably not all three of them. So I hooked up a power supply. Symptoms are I get a red and blue LED, then the red only, then they all go out. The FIP initially shows that the device is connected (Connecting to altimeter on COM3...connected.) but then a message window pops up with the text
"No data received yet.
The Raven requires external power as well.
[It does not run simply off the USB bus.]
Please power up the Raven to continue."

I pulled it off the sled and noticed a part that is mounted directly under the USB port. It has a metal ring that appears to be filled with (possibly) thermal compound that has hardened to be more like RTV or dried silicon seal. The ring was loose, so I lifted it off figuring that it was likely damaged anyway. When mounted, this part is touching my fiberglass sled. There are two smaller surface mounted chips under the ring, mounted on the ceramic substrate.

Does anyone know what this part is? Is it a thermal sensor?

Does anyone have any other experience troubleshooting Raven's to the component level? Any input is appreciated.

Thanks,
Steve

That would be the pressure sensor it senses atmospheric pressure.

MarkH said:

That would be the pressure sensor it senses atmospheric pressure.

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OK, thanks. I thought the pressure sensor was on the top side, but no matter, this thing is obviously toast regardless. It's let me down twice so it's going in the trash.

If the pressure sensor id being pressed against the sled it wont measure pressure very well. That might explain some of the difficulties. I made that mistake in my first raven install.

watheyak said:

If the pressure sensor id being pressed against the sled it wont measure pressure very well.

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True. You need to drill a hole in your sled right where the pressure sensor is so it can breathe. Not sure if that relates to the OPs problems or not, but it might.

Doesn't Adrian offer some level of repair service for his altimeters (knocks wood I haven't had to find out)?

The standoffs that come with the Raven don't provide much clearance for the pressure sensor. I usually slide a piece of paper under mine to see if to see if there is clearance and call it good enough, but at first glance it appears as if there is no clearance. Drilling a hole below the sensor would be even better.

cvanc said:

Doesn't Adrian offer some level of repair service for his altimeters (knocks wood I haven't had to find out)?

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The featherweight altimeters website does not post an address, phone number or contact info. He works a full time day job. You have to troubleshoot by email exchange, and if he's travelling/ busy, he can take days to reply. I had a difficult time getting him to agree to retest my Raven when I suspected a problem. This lack of full time product support is the reason I will not buy another one.

cvanc said:

True. You need to drill a hole in your sled right where the pressure sensor is so it can breathe. Not sure if that relates to the OPs problems or not, but it might.

Doesn't Adrian offer some level of repair service for his altimeters (knocks wood I haven't had to find out)?

Click to expand...

It was not pressed up against the sled, I had it mounted on short, nylon standoffs, but I agree with the use of a hole. Since I still have one more of these things, I am thinking of giving it one more chance. The unit I was working on has failed me before; it typically stops recording mid-flight, usually just past apogee. The last two flights were in a 54mm minimum diameter all CF screamer. I hit ~12K on a K550 at October Skies with it last year (based on the Raven's initial Accelerometer data), but the main did not deploy, and it was a drogue only landing. That could have caused the hit on the pressure sensor, I don't really know. Last December, it wouldn't power up with a fresh battery (it had come up two nights earlier when I was prepping for the launch) but I figured I must have grabbed a dead battery, and since it was only a J flight, I didn't really feel I needed redundant electronics. My old reliable LCD800 did the work, and other than I lost it over night, it was a good flight. But the battery was dead, and the LCD800 doesn't record, so once again I didn't get good altitude data.

This bird is designed to fly on an EX "L" motor (34" of Swamp Gas) and would likely do well over 18K. I really need the data to complete my sims, and without the lower flight data, I just can't fly it. I really need redundant electronics in it for those flights, and I really didn't want to yank my RDAS Tiny out of my Comp4 (would need to mount another 9V, another switch, all that). The Raven with the power perch seemed like a good solution. But if this second unit gives me grief, I'm bailing on them. I'm likely moving the Altus Metrum products.

Thanks for the comments, everyone. Fast up, slow down, get 'em back!
Steve

Never fly a Raven alone. The only times I can be absolutely sure the failed recovery was due to the altimeter failing was with Ravens. Twice - once on the 23rd flight with a Raven 1, the other on the 5th flight with a Raven 2. I love the data they provide, but if the rocket is going to crash, it's not worth it.

Rocketjunkie said:

Never fly a Raven alone. The only times I can be absolutely sure the failed recovery was due to the altimeter failing was with Ravens. Twice - once on the 23rd flight with a Raven 1, the other on the 5th flight with a Raven 2. I love the data they provide, but if the rocket is going to crash, it's not worth it.

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That's a little harsh. I have flown multiple Ravens in multiple rockets, including my cert, and have never had a failure.
It might be fair to say multi vendor redundancy is beneficial - for any altimeter.

Worsaer said:

That's a little harsh. I have flown multiple Ravens in multiple rockets, including my cert, and have never had a failure.
It might be fair to say multi vendor redundancy is beneficial - for any altimeter.

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Not really. Programming can be quirky. Height 1, 2, 3 ? Really? I set what I thought was field elevation and the main chute channel didn't fire. Rocket was bullet-proof and landed in a pile of soft dirt so no damage there from just the 12" drogue
recovery. Ejection charge fired fine with a remote external application of power so the ematch was fine. Using the testing circuit on the Raven 2 all the channels were fine. Even did a bare ematch on the channel in question and it worked/popped. I did a factory reset and just set the main chute opening altitude and left everything else alone now. If it fails again the device is going in the trash and I'll stay away from the product. The altimeter always worked for 5 prior flights and didn't fire when I thought I was setting the field elevation manually. I don't know how anyone can figure out how to do staging with a modicum of altitude checking. Pretty confusing. No detailed manual or explanations on flight scenarios so I tell newbies to stay away from this product unless they know someone who "really" knows it. Kurt

ksaves2 said:

Not really. Programming can be quirky. Height 1, 2, 3 ? Really? I set what I thought was field elevation and the main chute channel didn't fire. Rocket was bullet-proof and landed in a pile of soft dirt so no damage there from just the 12" drogue
recovery. Ejection charge fired fine with a remote external application of power so the ematch was fine. Using the testing circuit on the Raven 2 all the channels were fine. Even did a bare ematch on the channel in question and it worked/popped. I did a factory reset and just set the main chute opening altitude and left everything else alone now. If it fails again the device is going in the trash and I'll stay away from the product. The altimeter always worked for 5 prior flights and didn't fire when I thought I was setting the field elevation manually. I don't know how anyone can figure out how to do staging with a modicum of altitude checking. Pretty confusing. No detailed manual or explanations on flight scenarios so I tell newbies to stay away from this product unless they know someone who "really" knows it. Kurt

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I think you are being very critical of the Raven. You have to remember the Raven was designed to be used by people who understood the basic science of the rocket in flight.

It is not an easy device to learn, but it was never meant for that. There is a reason the Raven is used in almost every high altitude attempt, its reliable and it can be programmed to do exactly what you want it to do.

If anyone is having problems with the Raven I would PM Adrian on the forums, he has responded to me before and has repaired one of my Ravens for $15.00, when it needed an overhaul.

Good advice for any altimeter. Always use two if you have room.

Rocketjunkie said:

Never fly a Raven alone. The only times I can be absolutely sure the failed recovery was due to the altimeter failing was with Ravens. Twice - once on the 23rd flight with a Raven 1, the other on the 5th flight with a Raven 2. I love the data they provide, but if the rocket is going to crash, it's not worth it.

Click to expand...

BLKKROW said:

I think you are being very critical of the Raven. You have to remember the Raven was designed to be used by people who understood the basic science of the rocket in flight.

It is not an easy device to learn, but it was never meant for that. There is a reason the Raven is used in almost every high altitude attempt, its reliable and it can be programmed to do exactly what you want it to do.

If anyone is having problems with the Raven I would PM Adrian on the forums, he has responded to me before and has repaired one of my Ravens for $15.00, when it needed an overhaul.

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But an online manual with screens of common scenarios for basic flights, staging and what have you would go a long way to clear the "air" on the device. An explanation instead of "this" is < "that" is too cryptic to "know" what the author of the programming
algorithm means. A paragraph describing in "longhand" what the screen save is doing would go a very long way to understanding the algorithm. Having to depend on a maker who has a day job too and may not be available when the user needs advice it would be prudent to have a clear tutorial available. Kurt