APRS Object now in OBEX

g3cwi · 2012-03-11 01:47

Hi all

I have posted my APRS object to the OBEX. It works rather well now after all the help from the patient people here. My biggest step forward was to buy a 4 x 20 serial LCD which revolutionised my debugging! The code I have written is in a naive style but is very readable (I think). I would welcome style tips.

It should use locks really but I could not get my head round their use in this context. It seems to work without. The stacks are far too large too etc etc.

http://obex.parallax.com/objects/849/

I hope that someone finds it useful - I know of one user already!

I have been pleasantly surprised at what could be done in a couple of weeks of spare time. The Propellor has a very interesting architecture.

Regards

Richard
G3CWI

Brian Carpenter · 2012-03-12 17:36

This is great. Thanks for posting this. I need to set up a board and try it out. Do you have any video of it in action?

pedward · 2012-03-12 17:46

Now that you have an APRS object, why don't you give my direct modulation code a try. http://forums.parallax.com/showthread.php?137751-DEMO-new-FM-broadcast-code-using-Chip-s-Video-mixer-method-explanation

You could direct modulate the signal with the Propeller, without the need for an HT.

A 100ohm resistor will give you 88mw of output power, 4.7k will give you 2.3mw of output power, so try the 4.7k first.

I'd bet this combo would be the bee's knees for a quadcopter, no extra hardware!

I still haven't tried it out on a spectrum analyzer tho.

g3cwi · 2012-03-29 09:39

Hi all

I hope to publish an update soon. This has some improved algorithms and adds special functionality for SOTA activations: auto-spotting (this is a unique feature never implemented before as far as I know). It also implements a mode switch which changes various parameters depending on whether the system is being used in a car or for hiking. Much more remains to be done and the code is still naive - but well commented.

Regards

Richard

g3cwi · 2012-04-08 09:24

Latest version now in OBEX.

73

Richard
G3CWI

kuroneko · 2012-04-09 00:25

You use

IfNot~~ON '***
    F.Start

to start F32 on demand (in FloatString). This is not the same (and doesn't really work) as the originally suggested

IfNot ON~~ '***
    F.Start

That said, it should probably be changed to the following sequence in order to avoid lockups if you run out of cogs:

ifnot on
    ifnot on := F.start
      return

The return could also be an abort. Furthermore, you call other methods which also require F32 being started so it would make sense to put the start call into the SetPositiveChr method which is called first (short of adding the sequence above into every method which requires support).

g3cwi · 2012-04-09 01:34

Hi Kuroneko

Thanks for spotting that. I have altered it and will upload to OBEX.

Regards

Richard

g3cwi · 2012-04-11 13:13

Dear all

A serious bug came to light today in V1.1.1. This was mainly due to me trying to be too clever which resulted in running out of cogs (I think). V1.1.2 is now in the OBEX and seems to work.

Field testing tomorrow.

Regards

Richard
G3CWI

JAComms · 2012-04-19 04:08

Hi

I have been playing with you APRS object and its working well. I have been trying to get the demodulator to work but with no luck.
Have you had any joy with thi as yet??

73's

Justin - VK2HJA

g3cwi · 2012-04-19 07:27

Justin

Thanks for the feedback. The OBEX object still has a few little bugs left. I will upload the fully working version soon. I have used my system very successfully on several hiking trips - it works just fine!

I have not experimented with using the Prop to receive packet. It was not a feature that I really needed. Perhaps you can take the APRS object to the next level with RX as well as TX fully implemented?

73

Richard
G3CWI

APRS Object now in OBEX

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