<#part sign=pgpmime> On Mon, 13 Feb 2012 21:14:49 -0800, Casey Barker <[email protected]> wrote:
> 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). Ah, all is clear now -- the 2 second delay was internal to the TM. The TM reset just under two seconds after apogee. (apogee at +27.68s, last data at 29.49s). TM would have sent a couple of packets past apogee indicating drogue state; perhaps they were just lost? > 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. Yeah, it's like your board doesn't have the fix installed; once we stuck a cap across the LDO input, we couldn't cause *any* kind of voltage drop on the 3.3V rail. > 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. I've thought about this. I coded up bits of it a few months ago; of course, it would require talking to the TM board over USB, which makes it less than ideal from an electrical perspective. > 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. Yeah, it's always a tight squeeze to add anything to the TM code. > 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. Sounds really clean. Let's see if Bdale has any other suggestions on how to test stuff; if I had the board in hand, I'd hook up a meter to the 3.3V rail and then take a high power transmitter (like a regular HT) and see if I could get it to drop at all by holding it near sensitive bits of the TM. That's how we diagnosed the missing capacitor issue... -keith _______________________________________________ altusmetrum mailing list [email protected] http://lists.gag.com/mailman/listinfo/altusmetrum
