Some professional rockets and spacecraft use capacitive discharge, but others use direct battery current. The latter technique wins the design trade in most spacecraft applications due to lower mass...
Type: Posts; User: Adrian A
Some professional rockets and spacecraft use capacitive discharge, but others use direct battery current. The latter technique wins the design trade in most spacecraft applications due to lower mass...
The baro data is much more accurate for apogee altitude than the double-integrated acclerometer measurement. Looking at the data, it looks like the FIP and the Raven were using a little different...
The firmware for beeping out numbers is done. One new and improved feature is that high beeps (used for regular digits) and low beeps (used to represent zero) each have their own corresponding LED...
On a little bit of a tangent, lithium polymer batteries have a nice relationship between their voltage and their state of charge. When a lipo cell is pretty much empty, its voltage is 3.0 volts when...
In the Jart case, only the main and apogee channels were connected, and they both show a small voltage drop around the same time that the battery has the dip. In the case of the Darkstar on the J...
Just a reminder that the current described by a lipo battery C rating, even in burst mode, is generally significantly lower than the current that would be produced in a short circuit. I would be...
I don't want to make any promises on time until I have a complete version of firmware and I've done some alpha testing. Then I'll make some altimeters for beta testing and take advantage of the...
Update:
The hardware is pretty refined now, but the firmware is coming along slowly. I started fresh with the Sparrow code, to use better software coding practices than I have before, and make it...
Yes, even in the simulated flight they happen at slightly different times, so you can review the recorded data and see exactly which event triggered each output.
Possibly. Interesting idea. Try...
Not quite. More like the flight data shows that the apogee channel was actually set up to use the acclerometer V<0 with no delay, which explains why some accelerometer measurement error caused the...
The FIP does support the 250G Raven3s. For all of the 250G, single-axis Ravens, the 1st and 3rd orientations provide the axial calibrations, and the 2nd and 4th positions are ignored. By the time...
It's going to be a little while, but I'm still making progress on the Featherweight Sparrow.
NCR does generally abide by the requirement not to fly into clouds. When I was an RSO with that club, I have turned away several rockets that would have gone into the deck when we have had overcast....
The GPS receivers don't need to be rebooted; they will re-acquire lock on their own when they can. The better rocketry units get the lock back well before apogee, and others re-acquire around...
The Power Perch does not have a battery cut-off. When it's powered off, it drains the battery around 1% per day.
The 130mAhr batteries I sell on my site and include with the Featherweight av-bays don't have any cell protection circuitry, so unintended cutoff under high currents is not an issue.
Just for test purposes? That's much too high to use in a firing circuit with the small single-cell Lipo batteries under discussion. In a Featherweight av-bay setup, the battery has about 500 mOhms...
That's correct, and I'm glad to see you found how to select the different flight events. I think while I'm updating the manual I'll put in some instructions that I thought I already had in there, on...
Thanks for the review.
Yes.
Actually, the default settings now has the backup main set for AGL3 < 480 feet and no delay. Also I'm changing the table to correctly show that the default...
The accel-derived velocity check that's part of the default baro-based apogee detection will prevent any high-speed deployments on the way up. When the rocket is moving more slowly, the specifics of...
In the most recent version of the manual (June 12 2012, available on-line here: ), it correctly states that the default apogee detection is barometric. Could you tell me where you got the old...
The Raven and the 29mm av-bay were designed for this case. The recovery deployment outputs are independent from the stage ignition. Also, you can set the stage ignition with an altitude trigger so...
Calibration can't hurt, and I do it when the upright or upside-down Gs read outside of 0.95-1.05. That's part of my pre-flight routine of checking that all the real-time data from the Raven looks as...
I make and sell small single-cell Lipo chargers and batteries here:
http://shop.featherweightaltimeters.com/category.sc;jsessionid=4E239B11ECCD2EF60431FE926FC722A2.qscstrfrnt06?categoryId=2
The...
Modern integrated circuits for embedded systems have been quickly switching from 5V to 3.0 or 3.3V as a standard compatible voltage. Just a few years ago, finding sensors that operated below 5V was...
The diagram on post 1 and post 8 both look correct.
-Adrian
Was that this one?
http://www.rocketryforum.com/showthread.php?42957-Post-your-Raven-FIPa-files-here&p=515443#post515443
That's why I like the really small Lipos, 130 mAhr or 160 mAhr. They are very abuse-resistant, they don't put out enough current to damage Featherweight altimeter outputs even in a short, and they...
Soldering on a 0.1" pitch header is a viable option, but wiring straight to the header block doesn't need to be difficult. With appropriate-gauge wire (24 or 26) it's pretty easy to twist 3 or 4...
It's not a shorted output because the battery was down for more than the 1-second on-time. After 1 second is up, the output switch would open to cut off the short. Also, the battery dropped out at...