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Small and simple Flight data display

PostPosted: Tue Aug 02, 2011 7:07 am
by Helno
Wondering if there is any interest in a simple flight data display.
It would give you things like altitude, rate of climb, airspeed (good down to about 15 mph), RPM, and optionally EGT or CHT or magnetic compass.

I got the idea after seeing my uncle Glens instrument pod and realising how silly it is to have an airspeed indicator that can hardly read below 25 mph and paying hundreds of dollars for a pair of tiny tachs seems a bit outrageous.

Most of what I want to do comes from a few open source projects namely the Arduino project and the Ardupilot project. The Arduinio is a microcontroller system that allows for rapid prototyping of small and simple electronics it is a very inexpensive peice of hardware and the software is free. The Ardupilot project is an autopilot for R/C aircraft and has a large amount of mature code for reading the various instruments that small lightweight aircraft could need.

My prototype is up and working that reads altitude and displays it on an LCD it took only a few hours to get that stage from a box of parts and a few coding manuals.

I have been playing with power systems and I think a 4 cell nihm AA pack will run it for plenty of time and can be recharged with solar cells nabbed from a few $3 solar lamps or in a pinch alkaline AA's could be used.

Let me know if there is any interest and if there are any coders out there who are interested in cleaning up my code feel free.

Re: Small and simple Flight data display

PostPosted: Wed Aug 10, 2011 4:02 pm
by Chaosrider
Hi,

I for one would be interested in that kind of project. I actually started on a RPM reader project a while ago to the point I got the code mostly working ( I was in the process of fixing a debouncing issue either through software or hardware) and building the actual sensor circuit.

Is your code in Arduino ? I have an Arduino compatible board (mostly, it is actually a Teensy board) but I did all my coding in C

If you wish to talk about it,PM me for my msn address.

And here is a link to my code :
http://ubuntuone.com/p/rir/

Re: Small and simple Flight data display

PostPosted: Sat Aug 13, 2011 7:57 pm
by Helno
I'll have to take a look at your tachometer.

Shortly after I started my project I found this one. http://dangerpants.com/labs/adi/userguide.html he is now way beyond what I had made.

I am terrible at programming and am really struggling to get my project off the ground. What this guy has achieved is missing only a handful of features and I am sure they would be trivial to add on.

I basically wanted to add on servo driven gauges for airspeed and rate of climb and add EGT and Tach to the display. It might be easier for me to just do some type of work for Ian and get him to write the code.

Re: Small and simple Flight data display

PostPosted: Sat Aug 27, 2011 12:44 pm
by Chaosrider
That sure looks promising, I will definitely check it out when I have a minute.
For the gauges, LCD is the easiest way to go, but for dials, I would'nt use servo driven stuff but look instead for electric driven ones.

I think adding EGT and other temp sensor would be trivial but Tach might be a bit trickier (depending on the sensor used)

Re: Small and simple Flight data display

PostPosted: Mon Oct 10, 2011 3:11 pm
by Helno
I think I am going to go in a different direction with this project.

You can buy a really nice altimeter/ASI for a reasonable price and my GPS will work ine as a compass.

What I think will be a more usefull is just an engine information system. The fact that Tinytachs have non-replaceable batteries makes me want to find an alternative.

I think a hall effect sensor will be a better option for detecting RPM than an inductive sensor. Once it is in place it will not need to be fiddled with unlike the inductive sensor coming from an ignition wire.

My understanding of the Rotax 185 flywheel is that it has 4 magnets 2 north facing and 2 south facing. A latched hall effect sensor should give a nice square wave off of that with 2 pulses per revolution.

The code for a simple Tach is pretty basic.

Here is a good example.
http://blog.nsfabrication.com/2009/06/2 ... ontroller/

Re: Small and simple Flight data display

PostPosted: Mon Oct 17, 2011 10:54 pm
by Shannon
Best thing to use (in my opinion) are the 2-1/4" Westachs. Very easy at a glance to sync the engines. Your eyes pick up slight difference in the needles quite easily. Little 2-inst side by side pod is all you need. Sucks using dual digital readout to sync the engines. I use tiny tach on one engine simply to log engine run time. 0-70/80 ASI in bullet case with remote Pitot tube or hall indicator will work. I hardly look at anything but the tachs anyway. After a bit you could take all the junk off and fly the plane with nothing. I have Alt, ASI, GPS, Twin Tachs, Bank indicator, clock and compass. Don't need any of it really Haa Haa !

Re: Small and simple Flight data display

PostPosted: Tue Oct 18, 2011 6:47 am
by russell
I'll bet you text will flying also!

Re: Small and simple Flight data display

PostPosted: Tue Oct 18, 2011 7:04 pm
by JPXman
IMHO an EGT gauge is a must for a new lazair flyer. Even for veterans after an overhaul of an engine. Personally I would fly with an ASI and two EGTs over anything else (well tiny tach of course, they are so cheap and bulletproof!).

EGT will instantly tell you the condition of your tuning job. seasonal, and for some, montly tuning is sometimes necessary and the rpm/EGT combo makes it really easy.

geez i gotta get off my butt and get my plane back in the air i'm jonesing for some lazair time!

Re: Small and simple Flight data display

PostPosted: Wed Oct 19, 2011 7:32 am
by Shannon
russell wrote:I'll bet you text will flying also!



I tried that Russell but the Geese (which are arriving early this year) keep honking for me to get out the way.

Based on my long 185 experience I'd say skip the EGT's. No way a NEW guy is going to be able to make any sense of tuning the engines paying attention to that. It's hard enough for a NEW guy to understand what's going on with the engines as it is. IMO time is a better spent learning precise ignition tuning (TDC dial gauge method) and proper carb overhaul-adjustment (per the manual). If a new guy builds himself a test stand and follows long established tuning-maintenance-rebuild procedures the engines will run properly and be super reliable. I've seen many guys many times try to out-think the established 185 routines and to date it has never worked ONCE. All that has ever produced is god awful running engines and bent planes. You can take that to the bank !

Re: Small and simple Flight data display

PostPosted: Mon Dec 19, 2011 9:04 am
by Wayne
Check out 'Kangook Paramotor' websites there's a simple unit with rpm, feul, egt , speed, cht alltogether in one unit for $250 ?? including sender units I was thinking of having a 3 way switch to check each motor indivdually rather than having 2 units ? then you would just have 2 senders connected to a switch mounted somewhere at start up you can swith to each motor and every now in flight switch over to check ? there already out there also wireless throttles are available as well ?