<p>It is basically a circuit board with a couple integrated circuits and a pressure sensor. The altimeter works by sensing the change in outside air pressure. There is also an LED light that blinks the altitude after a flight.</p>
<p>sweet, any pyro outputs?</p>
<p>are you off-loading to flash, eeprom or what? what is your read rate? did you develop the protocols and stuff?</p>
<p>how much do i have to bribe you to come here? wait… i shouldn’t be bribing… ;-)</p>
<p>“rocketDA: Rocket Boys and October Sky are anagrams :]” - lol. yeah, i know. :)</p>
<p>Lol its a little late because im not applying to Mudd. Where is Mudd anyway? We didnt develop the algorithm for the chips we bought them from a company online. We can continue to add on to the board to customize the altimeter for drogue and main shoot deployment at specific altitudes. I think the read rate is 5 per second.</p>
<p>Are they Parallax chips? Are you using transistors for the pyros? isn’t 0.2 sec readings a little slow?!</p>
<p>rocketDA: it’s probably easiest to write to an EEPROM thoughout flight. you can buy an EEPROM chip for like $2 and it’ll store 8192 bytes, or 4096 words (not sure how familiar you are with programming, but pretty much a word consist of 16 bits, meaning you can store a number anywhere between 0-15535, or the number of rows in an Excel sheet). if you’re reading 20 a second, that gives you 204 seconds of flight logging.</p>
<p>Ya it is pretty slow. We havent set up the pyro system yet so im not sure. Its just a basic kit we bought so we could become more familiar with circuits before we get more complex. It has the ability to add more on. I wish it did have a faster read rate, but its our first so as long as it works.</p>
<p>yeah… 5Hz will be functional… just not good for research stuff or analyzing shocks and stuff. with our new boards, we’ll be sampling at 20kHz on 16 analog channels (12-16bit) and 8 digital channels. because of the high volume of data, we’ll be needing 512MB flash drives. i’m definitely not the expert here… another team is building them for us.</p>
<p>your altimeter is mach immune, right?</p>
<p>oops, I meant 65535, not 15535.</p>
<p>How does mach affect the baro sensor? I’ve read that people use accelerometers for the first few moments during mach flight, and then switch to baro later on, but I never knew why.</p>
<p>and that’s a lot of data! which microcontroller are you using?</p>
<p>Wow I didnt know about the whole mach immune part. I dont think it is. How does breaking the sound barrier affect the pressure sensor.</p>
<p>sound’s a pressure wave, squish all of them together and you will measure a huge peak. you dont get that?</p>
<p>also, rockets are cool.</p>
<p>How much was the total cost to build the altimeter, I’m getting tired of losing them when our rocket lawn darts. At 60 bucks a pop its not cheap!</p>
<p>Yeah, actually, those guys that make the altimeters aren’t raking much money. The sensor themselves are $17 from digikey. If you build one yourself using Parallax’s Basic Stamp, you’re running at a minimum of $29 just for the microcontroller. There are microcontrollers out there that run for like $5 each or so, but you would need to learn assembly language.</p>
<p>“and that’s a lot of data! which microcontroller are you using?”
something like “black____”. i don’t remember the name of it. i just remember “black” is in the name.</p>
<p>(it doesn’t help that this isn’t my section of the project)</p>
<p>oh yeah! they are called Blackfin processors (Analog Devices, a sponsor). Ever heard of them?</p>
<p>whoa, that’s tight… I’ve never heard of the Blackfin processor, but I do use accelerometers and ADCs from Analog Devices for my altimeters!</p>
<p>yeah. Analog Devices has some really awesome stuff. our boards will be running around 550MHz thanks to AD</p>