Hi Keith, thanks for the response. On Mon, Feb 13, 2012 at 8:51 PM, Keith Packard <[email protected]> wrote:
> I don't seen the usual accel spike from the drogue charge in the plot, > and the plot data ends almost exactly two seconds after apogee; did you > have the raven set to fire a drogue charge with a two second delay? > The TeleMetrum was configured for a 2-second apogee delay and did fire a Rouse-Tech CD3 (CO2 cartridge) for drogue. I think the use of the CD3 is why there's not much of a bump. The Raven was set for 4 seconds and connected to a BP squib. I know the Raven blew after the TeleMetrum because there was no BP residue inside the airframe (unlike for the main). For what it's worth, on my first flight of this unit, I misconfigured the Raven and it fired the drogue BP a couple seconds early. In that flight, I saw a clear pressure spike in the TeleMetrum data when the Raven blew the drogue, and later, the TeleMetrum successfully fired the main CD3 with no apparent bump. (It then reset immediately after deploying main.) So it seems like a similar issue as last time, but just reversed drogue/main. >From what I can see, it looks like there's some kind of interaction > between the two flight computers, so you'd need to ground test the ebay > with both turned on and then try firing a drogue charge from the Raven > to see what's happening. > I don't think this is it, based on the above description. But I have gone through the Raven's flight cycle on the bench, and it doesn't seem to interact with the TeleMetrum. I was actually thinking that a feature similar to the Raven's "simulated flight" would be really useful on the TeleMetrum. Being able to fire charges on demand is oh so helpful (more useful than the Raven, frankly), but it doesn't properly simulate the combination of firing charges and tx'ing live telemetry. I think that's where the issue lies. I've poked around the TeleMetrum code, but I don't know it well enough to add this feature myself yet, and I'm not sure there's room for it. > Have you sent pictures and a schematic of the ebay? We might be able to > suggest > some wiring improvements to reduce interactions between the two boards, > if that is indeed the problem. If so, we'll also try to figure out how > to fix the system so it doesn't happen even with the original wiring. In short, it's all #20 stranded copper wire, with a tight twist in all the leads to switches and igniters based on the RFI lessons learned in my 54mm Little Dog. The wiring harness uses the 4-pin 3M connectors and the rotary voltage switches from the Altus Metrum site. All of the wiring is completely independent from the Raven, and the Raven is on the opposite edge of the bay, as far away as it can be in a 5" airframe. I'll send photos in the next day or two. Thanks, Casey
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