Arduino altimeter & airspeed indicator

Discussion in 'Instruments / Avionics / Electrical System' started by cluttonfred, Apr 8, 2015.

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1. Feb 29, 2016

choppergirl

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I probably watched the Ben Heck Show... way too much...

I think I'd also like a numpad, with maybe one more row of digits (or simply switching modes and use whole display when numpad is depressed), for entering a verb and object to the computer, and an execute button, for changing internal values on the ground, like the Apollo spacecraft computer did. For example, high and low ranges for every display, go flash the dots and give a verbal warning when outside range. The speaker is so you can hear output on the ground without having to put ear phones in... and maybe an "attract mode" routine like pinball / arcade machines had, for the occasional kid that wants to sit in your plane.

2. Feb 29, 2016

cluttonfred

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3. Feb 29, 2016

Floydr92

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That would quickly become very annoying!
I like the tablet idea, could quite easily make a diy glass cockpit with an android tablet, sure, not as accurate and reliable as the likes of a dynon skyview, but at a fraction of the cost and for VFR flight, would suit me just fine.

With regards to using stepper motors, i would stick with setvos as they have a built in kinda position sensor (well, just a ceramic potentiometer). Stepper motors dont have this, and although they can be more accurate, i think its overkill, and you will need to buy stepper motor drivers for the arduino too.

In the arduino library theres a simple sketch which allows you to move a servo with a potentiometer. So you turn the pot and the servo turns, turn it back and it turns back. If you start with that sketch, and replace the pot with any other resistive sensor (pressure sensor being one), you should get the same output...servo moves in relation to the variable. You can then adjust how fine or coarse the movement is in the sketch.

Another option would be to couple the arduino to a raspberry pi and you can have a hdmi conection to a small screen. Thats a possible hard wired variant of the tablet idea.

Have fun! (I'm going to go and play with my arduini now)

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4. Feb 29, 2016

choppergirl

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Its only annoying because its using an old school style voice generator from waveforms so it can fit in a low spec small hardware package. Speach synthesis has come a long way since then, so much so its almost indistinguisable from human speach.

Play around with Ivona https://www.ivona.com/us/, for example. My favorite is Australian: Nicole. Change voices, punch in some numbers and warning messages you think up.

You could also program in all the warning messages just like big airline systems feature: Warning: pull up! Or count downs of altitude as you land under 100 feet. Compass heading variations, engine running hot, fuel level low and fuel level critical, approaching stall speed, etc. I would give mine a little snarky personality beyond just being a slave reporting system.

If I wrote it in python, I could program a pretty fair bit of conditional intelligence into it to eliminate spurious reports thst are non-reports or that you dont want to hear, that a more primitive system does not do. That would cut out a chunk of the "annoying factor" too. Dont talk to me all the time, just when theres a real problem developing or **** is about to hit the fan... or talk lots if I want you to like about things I really want to know on take off or landing, but keep it succinct.

Of course, using a nice sounding voice you like will probably require you to go way beyond using an arduino or minimalist controller board. That will add some bulk, weight, and larger power requirements, but pc miniturization has also come a long way. But you dont need the latest, something Less shiny could work fine. My webserver, for example, is running on a completely obsolete solid state thin client minipc the size of a book, with only 400mghz and 128mb ram, and uses 8 watts. My upload speed limits it's performance far before the ancient specs do.... the thing is 15+ years old.... but you know what, not a single fan or spinning drive on it to fail.

I love tablets, I'm on one now, but the absolute LAST thing I want to be doing is hammering away trying to press buttons on a glass surface in bright sunlight inside a noisy, windy, vibrating ultralight with no autopilot. Maybe it would be good to display a navigation map with waypoints, something you didnt have to change until you landed, just to keep you from getting lost in the air or help you in the air. But I would hope I wouldn't have to try and operate it with finger presses while flying. On big jet planes with autopilots and long stretches of safe, boring, straight flight, it's different, you can fiddle fart on a tablet or glass screen after you reach your altitude.

Last edited: Feb 29, 2016
5. Feb 29, 2016

cluttonfred

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That text-to-speech link is a great resource, choppergirl, thanks. I agree with you that the voice sythesis can be made a lot better than the Gipsi one, which is already several years old. I actually gave John Benedict of Gipsi a plug on my site back in 2010: Clutton FRED - A Gipsi for your FRED?. I also agree with Floyd that any voice data annunciator, even if the voice sounds perfectly human, would get old except in small doses. Still, as long as you could easily switch it on and off, it could be very useful for the designed purpose, which is keeping your head up and looking around instead of looking down in the cockpit. The Gipsi interface is a little clunky, but if you could wire, say, a hat switch and sound on/off switch to the joystick, it could be very handy.

6. May 27, 2019

Charles_says

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Unfortunately "bubble" display, is no longer produced by "Sparkfun"

7. May 27, 2019

rotax618

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8. May 27, 2019

Saville

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I looked into making a flight data recorder using an Arduino but I found out that a Raspberry Pi is a better option. A GPS module is available as is a differential pressure module (gives you pitot airspeed in addition to the GPS ground speed) as well as a temperature module for OAT.

But electronic flight bag tools like Foreflight gives you everything except OAT and airspeed in the saved tracklogs. So for flight testing I record the OAT once I reach a test altitude. and record airspeed from the EFIS.

Still, it would be nice to have a Flight Data Recorder that records all of that which can then be downloaded as a file and used in data reduction tools. So when I have the time I'll build a FDR with the Raspberry Pi.

9. May 29, 2019

pwood66889

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But back to the original Arduino. I am working on a friend's Weedhopper, and the altimeter is missing. Having that and the rest of the stuff mentioned (vert. speed, air speed) would also be nice. From what I saw of the original, it has a small, red LED display. I would like something that is readable (by poor, old eyes!) a few feet away. Update?

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10. May 29, 2019

Charles_says

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http://experimentalavionics.com/ is the unit I am going to build...using the Can-Bus, The Data Recorder is part of it...also their AOA gauge. along with some mods, I can get "Heavy" messages like" Terrain Pull up!!" in a sexy voice!
Hey, at my age (73) you want all the "sexy" you can get! Ha Ha !

I have already built a"Raspberry Pi" ADSB-in that sends data to Foreflight,
and IR tach using the "Arduino Nano",
using the Arduino Nano and a 16P x 2row display module

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11. May 30, 2019

Bill-Higdon

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Percy, I sent you a PM

12. May 30, 2019

rv7charlie

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I wrote the expav.com guys a long time ago, asking why they don't consider the option of readily available smart phones/tablets for the display. Unlikely to cost any more than what it takes to get a display working in a case, *much* higher resolution for better graphics, and *color*. (This is significant, for readability and prioritizing info.

Charlie

13. May 31, 2019

282ex

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Just a guess that cost/complexity was a factor. The idea was to spend as little as possible. Back the phone screens were spendy in comparison.

14. May 31, 2019

Hephaestus

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Altimeter would be pretty easy, https://learn.sparkfun.com/tutorials/bmp180-barometric-pressure-sensor-hookup-/all

Potentiometer to set barometer

7 segment display https://www.allaboutcircuits.com/projects/interface-a-seven-segment-display-to-an-arduino/

Could go fancy and run one of the Nixie tubes like a 70s era Russian jet... Those can be super Bright.

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15. Jun 2, 2019

pwood66889

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Good seeing the code. Altimeter would take 4 or 5 of the 7 segment displays. Thanks for the tips!

16. Jun 2, 2019

cluttonfred

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You might take a look at this battery-powered, monochrome solution or this externally-powered, color solution, both of which include 1" diagonal OLED screens already mounted on Arduino-compatible processors. Add a rotary encoder dial/button and the atmospheric sensor and mount it all through and behind an instrument hole blanking plate and you're all set.

17. Jun 2, 2019

Hephaestus

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18. Jun 2, 2019

282ex

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I just revisited the experimental avionics page. It hadn't been updated in quite sometime and was pleasantly surprised to find new updates.
http://experimentalavionics.com/efis-ver-2-0/
I was also pleasantly surprised the right tools being used for the right problem. Rpi being used for data recording although I would update it to run from an SSD rather than a microsd card (I'll provide a link how to do this if you are interested) as RPI's running from sd are known to lockup, just ask the stratux users. I dont know much about canbus so I'll reserve any judgement. Another adjustment I might make is to use a single teensy (arm processor) and have dual instruments or individual arduinos per instrument.

Thanks for bring the topic up!
Erik

19. Jun 4, 2019

Scheny

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I just stumbled over this thread for the first time. I am a senior expert on embedded systems, and I already did a project of a digital alti/variometer 16 years ago when there have not been any good sensors available yet (needed to be done with resistive bridges). So, I have some background in this area and can support if you have questions.

First input. DO NOT USE THE BMP180 SENSOR!!! They have been invented by Bosch for their engine ECU's to have a cheap way of altitude correction for gasoline engines. I have worked for them a few years and these sensors are for use cases where it is sufficient to have 100m of resolution.

They have the benefit of being cheap and offering a digital interface, so you spare the complete analog circuitry which can be a real pain in the ass to develop (huuuuge errors).

Use the MS5611 sensor instead and you will save a lot of troubles. Here a comparison between these two used as a variometer without filtering. See the difference (blue line in the bottom window):

20. Jun 5, 2019

pwood66889

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Looks like $6 to$10 a pop, Scheny. Wonder how the pin outs are. Would they be in the standard libraries?