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Jan 10, 2007, 03:19 PM
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A new project: RPV cockpit


I decided to start my own OSD (On Screen Display) for FPV/RVP (“First Person View/Remote Piloted Vehicle) project and call it “RPV cockpit”. The main purpose is to superimpose GPS and other useful information of the video signal that is being broadcasted.

I was inspired by another project started by AndyOne (https://www.rcgroups.com/forums/showthread.php?t=592531) that is composed of BOB4 (http://www.decadenet.com/bob4/bob4.html) OSD module, a Basic Stamp for interpreting the GPS data and driving the OSD module, 2 PIC controllers and a Garmin GPS with screen and keyboard. This setup could have fitted my needs but I wanted to replace the Basic Stamp with another PIC controller.

Somebody drew my attention to this “BlackBox” platform: it houses a standard OSD chip (STV5730A) and a PIC16F628 (http://www.blackboxcamera.com/stv5730a/gpsmod.htm). My idea is now to replace the BOB4 and the Basic Stamp of AndyOne’s project, by this board and replace the PIC16F628 code.

Many people report that wandering off and loosing orientation is an issue with RVP. So in the project of AndyOne, the GPS is configured to constantly calculate the distance and bearing to the pilot. This information is than displayed on the screen. In addition it allows the system to drive the rudder in case radio contact is lost so that the plane automatically flies towards the pilot and control can be regained.

In my project I would like to replace the GPS by a simpler one that just reports the actual coordinates. This means that the distance and bearing to the pilot will have to be calculated in the PIC.


Phase 1 features:
- Data: bearing and distance to pilot, speed, altitude, GPS precision
- Multiple screens with different amounts of detail, driven by knop on the transmitter
- Bearing and distance to pilot computed by PIC, not the GPS


Phase 2 features:
- Changing settings via transmitter
- Indication of values out of range (too far, …)


Phase 3 features:
- Integrate with external system for additional information: motor current, integrated current (mAh), receiver signal quality
- Integrate with external system for “rudder home”



The main tasks and challenges are:

- Setup a C development environment for PIC (until now I have only written small projects is assembler)
- Write code to decode NMEA (standard for GPS messages)
- Write code to calculate heading and bearing to pilot. By preference, without using floating point operations (as the libraries are big)
- Write code to communicate with the STV5730A chip
- Write the actual application

A major risk is that not all features fit in the PIC controller. If I want to use the Blackbox platform, I am limited to the 16F628. The 16F648 has 4K rom and a bit more ram and could probably also be used.
Last edited by FredericG; Jan 21, 2007 at 04:10 AM.
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Jan 11, 2007, 10:11 PM
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4mla1fn's Avatar
nice. we're on the *same* wavelength. i just started flying rc in october for the primary purpose of eventually flying fpv; i hope to be doing it by late spring.

most of the ideas you're described are one's that i've considered also. in december, i shared some of these ideas (e.g. displaying bearing and distance to home) with the owner of hitt consulting (the makers of another OSD and he indicated they'll soon be coming out with a new OSD/GPS module. i'm eager to see what he produces. it might be a good platform to build your various phases. anyway, i'll continue following your blog and would be willing to help out once i get my fpv gear and a few flights under my belt. peace.
Feb 02, 2007, 10:42 AM
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wedge98's Avatar
very nice. If you need any support in this department I have a degree in Computer Science and Engineering, I am a systems modeling engineer, and I am pursueing my Master's degree in CSE. I've done a fair amount of work in C and Assembly so I could lend a hand in looking over code or writing code if you want.
Feb 02, 2007, 12:03 PM
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FredericG's Avatar
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Quote:
Originally Posted by wedge98
very nice. If you need any support in this department I have a degree in Computer Science and Engineering, I am a systems modeling engineer, and I am pursueing my Master's degree in CSE. I've done a fair amount of work in C and Assembly so I could lend a hand in looking over code or writing code if you want.
Thanks.

Yesterday the PIC with the bigger memory arrived and finally I was able to put all code in the controller for a first integration test. It works, the distance and direction to a fixed point is calculated and displayed on the OSD. I seem to have some timing issues, which makes that some GPS updates are skipped. I will look into this the coming days.

So the project is coming to live but this does not mean everything is finished. The calculation part for example still needs some work. For example, it will only work for north-east coordinates. There is also room for improvement in terms of memory footprint and calculation speed. Is this something you could be interested in?

Frederic
Aug 14, 2008, 07:35 PM
Old retired Electronics Fart
Charles B's Avatar

C complier


You was going to write a C-Complier. Well check out this site.

http://microchip.htsoft.com/products...rocompiler.php

The Lite versions is free and it handles 10,12 and 16 MPU family.

While your at it check out this PDF file. If you went to the PIC32

processor you have all the power , speed and Memory you would

every need. They have wrote PSK31 Digital modem for the 16 bit ver.

in C of course. The source is off one pages in the PDF file.

The PIC32 starter kit is only $49.95 USD.

The starter kit page is

http://www.microchip.com/stellent/id...GE&nodeId=2591

Hope this helps.

WB8LGA
Charles


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