Casey Barker <[email protected]> writes: > Thanks, Keith! That's exactly what I needed to know. And yeah, I'm happy to > do a bit of firmware hacking. I'll be curious to see what others do with > the extra capabilities.
There's a lot of hardware on that board. While we log all of the raw sensor data, the board is using the 3-axis accel only for measuring the initial orientation on the pad so that we can get absolute angle from vertical during flight from the gyros, and we're not using the compass data at all yet. > 100 Hz is likely enough, though the team was musing about an old HCX that > could log the accelerometer at 500 Hz. (Indeed, the simplest solution might > be to just stick an HCX up in the payload bay for a flight.) More sensors is always a great idea :-) > If I needed to bump it up, rather than perturbing the sysclock and logging > format, perhaps I could borrow a hardware timer and just log a window of > the z-axis in a second file. Yeah, there are lots of available timers, so running another one at a higher speed and using that to drive the accelerometer for logging would work just fine; the actual flight mechanics use a 'blackboard' approach where the sensors dump data into a global data structure and the flight system just pulls out the most recent values, so having the accel run faster wouldn't require any changes there. > I didn't know it could do APRS, too... Neat. I recall the tx part was rated > for 16 dBm. Is that at 100% duty cycle? Could we interleave APRS just on > descent or landing? I smell feature requests, but if they make sense, maybe > I can help with implementation. Yeah, the new radio chip is a bit more flexible and can send arbitrarily long transmissions. APRS is just a 'really long' 9600 baud GFSK packet with some very strange bit patterns that generate the desired tone sequence. The new TeleMetrum uses the same radio chip, so it will also do APRS. Do you have one of the new TeleBT devices? That's really the best rocket tracker ever made -- live mapping on your Android phone, and state information including barometric height, battery and igniter status. -keith
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