GoFly is a project based on PNA (car navigation devices with Windows CE), LK8000 tactical fligh computer software and variometer (altimeter) external input based on Arduino board and pressure sensor.
-You can build this for about 150$,
-Your ordinary PNA (Personal Navigation Assistant) changes to really nice, high end flying computer, with lot of features and Arduino based altimeter and variometer let You see in real time your altitude, vertical and horizontal speed,
-Software let You log your flight in logfile, that is approved by FAI, so You can always claim Your flights in any competition,
-most PNA devices are much cheaper than dedicated flying devices
–GoFly gives You also nice altitude changing sound so You dont need to look into screen all the time to see what is going on in the air
-easily support competition tasks, with easy to understand user interface
-your PNA is still very good car navigation system, so it will be peace of cake to come back from any XC flying
Step 1: How this project works
So basically, device is based on two devices. First one is a PNA (car navigation) device which let You run extra software (LK8000 in that case) and second one is Arduino based altimeter/variomter.
Most PNA devices on the market works under Windows CE environment. When You turn on PNA, device is booting up and autostart navigation software. There is a lot of information over the internet how to “unlock” PNA devices to be able to run other software.
Other important thing is that we need physical interface to connect Your unlocked PNA do Arduino board. Many PNA devices has built in USB interface, but unfortunately we are not able to connect PNA with Arduino over typical USB pna port. But some devices (like few Mio models) also support serial interface (TTL logic, 3.3V) over usb port.
Second device is an Arduino board (Pro, Mini Pro, Nano) based on 3.3V logic with Atmega328 microcontroller, with pressure sensor board, speaker and extra battery holder. Arduino board is processing in real time air pressure, temperature, vertical speed (m/s) and pushing those values few times per second over dedicated protocol to PNA device running LK8000 software. LK8000 is taking those values and present in nice form on PNA screen during flight. Also very nice feature of every altitude/variometer is beeping noise sound. Arduino, when pilot is gaining altitude is beeping faster and faster letting You know that You are inside rising air. Rising hot air is what we called thermalls. During great flyable weather day pilots are able to soar hours, that is why we need extra battery pack. Average PNA device is capable to run without external power around 2 hours (about 300-400mAh power consumption with average 750-900mAh battery inside). Providing extra power let You fly few more hours with highest lcd brightness.
If anybody ask why doing all that if there is a lot of different devices for flying, new palmphones, iphones, android devices with dedicated software. The answer is easy for me. Most dedicated flying devices price range is around 500-1500$, user interface is miserable, with gray-scale LCD screens, with lack of information and less features. Iphone/Android devices cost also a lot, and flying software is using GPS based altitude to measure Your speed and altitude change. Unfortunately this is not enough. GPS latency is to big for usable real time thermalling.
So,basically the idea is to find cheap, nice looking PNA device, with good lcd screen, that we can see even in direct sunlight, unclock it, put LK8000 software on it, build small altitude/variometer device based on Arduino board with serial and sound output and connect everything together.
Also even without PNA navigation connected to GoFly, this is still full functional sound variometer device.
Step 2: What we need?
1. Mio Moov s501, s401 or Mio M400 car navigation system (You can do research over the internet to find other suitable devices). You can find those devices on ebay for around 35-70$ (You can also use other pna, but remember, we need good lcd screen and serial TTL 3.3v input). Mio is already tested by many paraglider/glider pilots.
2. Arduino Microcontroller board (look at your local Radioshack or SparkFun.com). You can start with ful size board, but if You feel confortable with small Arduino Mini and Nano board after some experience I think is a better choice.
3. Pressure sensor board
Those are very sensitive devices (resolution is about 25cm of altitude change) bt ou have to use some good algorithms to filter noise from those sensors.