Altitude Datalogger Update

T

testerrrs

New Member
For all the guys on here who helped me with this (thanks a lot!) here is where I have got so far.

Information on the circuit and how I built it. First (and only, so far) result at the bottom:
http://hexoc.com/altimeter/index.htm

Pictures of the transmitter module and captions/comments including PCB design.
http://hexoc.com/altimeter/tx.htm

I will post the pics and schematic for the reciever and the code for both parts up soon.

I'll keep that page/s updated, and I'll post back here when I make some more progress.

Again, thanks for all the help, and feel free to ask any questions etc.

Jon
 
M

manuka

Senior Member
Bravo- I'm most impressed with the sensitivity! As air pressure reduces ~1hPa for every 10m ascent, perhaps consider testing in a tall building lift, although pressure spikes may result from sudden door movements etc. Approx. how high does your rocket fly? This is quite a topical item given publicity from the recent USAF satellite shoot down !
 
T

testerrrs

New Member
Good idea on the lift, I'll give that a try. I know a couple of places that I can go and use the lifts for that purpose :)

The rocket I am testing with is an air powered thing: you know, foot pump into a pressure chamber and then let it all go at once via a charged capacitor and a solenoid. I reckon it goes about 150 feet. Probably more like 100ft or just over with the added weight of the transmitter module.

As I said, this is only for testing. Once I've established all is working properly, and I've made the thing as impact resistant as I can, I'll strap it to a fuel cell rocket and try that :) I have no idea how high those go, and how high it would go with the extra weight. The only "restriction", as such, is that the RF link is good only to about 300feet in direct line of sight.

Jon
 
M

manuka

Senior Member
300' LOS= peanuts for 433MHz. I get better than that in built up areas. Consider a better quality tx/rx pair, such as the Aussie Jaycar ones, or "cotanga" Yagi at the receiver. Stan
 
M

manuka

Senior Member
Straight up- about 10x that! My last model rocket experiences however date from the pre solid state 1950s-60s, so YMMV. The Jaycar 433 MHz tx/rx units are usually good for 1km LOS, BUT local UHF interference etc can massively chop this away. I recall past posts that lamented it was hard to even send data across the room...

Model aircraft & near space balloons have explored all manner of PICAXE telemetry (& "lost in the corn field" location beacons) based on cellular,FM, UHF-CB,2.4GHz etc as well. Errant breezes can blow such costly darlings off into the wild blue yonder of course. Google & check a past forum posting =>http://www.picaxeforum.co.uk/archive/index.php/t-3279.html Stan
 
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