Looks like there are quite a few types of CorrosionX out there. Which one specifically are you using?
On Jun 20, 2019, at 12:20 AM, Bryan Duke <[email protected]> wrote: FWIW, I’ve been using CorrosionX sprayed on a few different altimeters that get exposed to ejection charge gasses. I’ve only been doing it a couple years, but the boards all look corrosion free so far. To make sure the baros work, I’ve always put a little piece of electrical tape over the baro before I spray CorrosionX. I don’t know what CorrosionX would do to the internals of a baro, but my guess is that it’s not perfect for them. After I spray, I dab off any huge puddles of it and remove the tape. After several years and dozens of flights, you can still feel the CorrosionX on the boards. So, I haven’t resprayed any of them. I realize this is just anecdotal data, but it seems to be working for me to keep boards going. Keeping the gasses off is obviously better, but there are cases where ya just can’t make it happen. I have a couple rockets with TeleMinis in the nosecone just like you describe (no cable cutter though). I also have an EasyMini in a fairly similar setup in another rocket. No issues so far. One other thing I haven’t tried on a rocket is the technique that some quadcopter/drone pilots use on their baros of putting a little piece of foam on the top of the sensor. They do it to help smooth out the wind flowing around the sensor so that it gets smoother data. Something like that (foam + some hot glue) might add a baffle-like barrier that might help some. Just make sure it’s a pretty porous foam so that you’re not blocking the baro port. -Bryan > On Jun 12, 2019, at 9:48 PM, Keith Packard <[email protected]> wrote: > > Reinhard Rath <[email protected]> writes: > >> For a group project, I'm looking into replicatingfunctionality similar >> to the Jolly Logic Chute Release, but with a pyro cutter instead of a >> servo releasing a rubber band. >> >> For mechanical reasons, the EasyMini would be mounted in the nose cone >> and subjected to the ejection charge pressure. I'm not too concerned >> about damaging the sensor, the sensor in the JLCR seems to handle the >> same treatment quite well. > > While the pressure spikes are bad, the worst part is the corrosive > nature of the gasses generated. I've heard of people putting an > altimeter in a plastic bag so that pressure can be measured but no > gasses are exchanged; if you can think of a way to do that, the baro > sensor would last a lot longer. Otherwise, expect to replace the board > from time to time. > >> Do you expect issues from the pressures spikes regarding premature >> detection of the main altitude, or is there any other thing that you can >> think of the would preclude such "off-label" use of an EasyMini? > > EasyMini's Kalman filter should survive any weird pressure spikes you > impose on it. It works by ignoring 'crazy' data; data where the Kalman > error value is high, which indicates that the modeled altitude isn't > matching the measured altitude. > > -- > -keith > _______________________________________________ > altusmetrum mailing list > [email protected] > http://lists.gag.com/mailman/listinfo/altusmetrum _______________________________________________ altusmetrum mailing list [email protected] http://lists.gag.com/mailman/listinfo/altusmetrum _______________________________________________ altusmetrum mailing list [email protected] http://lists.gag.com/mailman/listinfo/altusmetrum
