www.shaneburrell.com Telecom – Electronics – HAM Radio – Test Equipment – Rescue

13Apr/120

Digital Modem Codec and SDR

I've be looking at several platforms to do DSP work in relation to a SDR and digital modems.  I have a xmos demo board and some AVR32 items laying around which I needed nice DAC/ADC to interface with.  The TLV320AIC23 is a nice inexpensive codec.  I built a small prototype board to use the chip in development products and later I'll turn this into a module that can just be plugged in to various projects.  This board can be used with a small MCU 16-32 bit to do APRS, GSMK (DSTAR), P25 and various other digital demod/mod.  The board breaks of all of the TLV320 channels for both input and output.

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11Jul/116

SB710Key – TM-D710A Keyboard Adapter

Prototype boards have arrived.  I'll be working with these for the next few weeks to hopefully finalize a line powered PS2 keyboard adapter for the Kenwood TM-D710A.  Here are some pics of the proto board.07/14/2011 - UPDATE waiting on some missing parts to arrive in mail.

07/20/2011 - All parts arrived except for the osc. It's on backorder for at least two weeks.

07/29/2011 - Still no osc.  I'm researching alternatives.

08/05/2011 - Finally located something that should work.  2 week leadtime on this part so more waiting.

11/30/2011 - I 've assembled and tested the few boards I had left and due to limited application of this I will be doing some sort of open source release of the project in December for those that want to build one of these and improve the software.

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3Nov/106

AVR based TNC/DIGI PCB based on 644p

Now I need some plastic to put it and the display in.

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2Nov/106

APRS TNC using Arduino with a display PCB Test

I've done a test layout to play with that I'll be testing in the next few days.  Below is the layout.

AVR TNC Arduino Shield Layout

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2Nov/100

APRS TNC using Arduino with a display.

Several folks have asked about using Arduinio hardware with APRS TNC.  I don't have a lot of motivation but figured I'd get the project started.  If you have an arduinio and would like to help develop this using arduino hardware please post (no emails please).  Here is the alpha schematic I'm working on using the display I started with in the original design.

Arduino TNC Shield

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21Oct/100

APRS AVR C vs Processing (Arduino)

I've gotten ton's of emails (100 or so) about the code for the APRS node I've been hacking away at.  I normally use an Arduino type board for prototyping.  However, the code is in C.  I do sometimes use processing to quick test something but generally things destined for the embedded world are in C.  Below are some projects I found related to what I am working on.  Some use the CML chips some don't. In the low cost model I don't use it.  I have been playing with a CML chip for digital type radios but they drive the cost up with what I am attempting to do which is build a device within the reach of just about any public safety department in volume.  And please if you don't mind, post questions as comments rather than emailing me directly.  That ensures that any Q&A can be seen by everyone.

http://garydion.com/projects/whereavr/   - This is a really nice setup, different application but very tidy setup.

http://sites.google.com/site/ki4mcw/Home/arduino-tnc - Hope to see more from this.  Its what more of you are looking for with PDE files provided.

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27Jul/100

AVR – CTCSS 2 Tone and APRS AX.25 project.

Brother Toner Transfer to PCB working!!!

AX.25 encode is complete and seems to work well.  AX.25 decode works, but I have a special mode and also have a CTCSS listen setup to remotely turn on that mode.  Still some items to do , but its almost time to put this on a board.  If you are interested in this project please let me know.  I was able to get my Brother Laser printer to work with the toner transfer method after some trial and error.  I had great results using a Brother HL-4070CDW and Kodak inkjet photo paper using a iron and being very patient with the soak.

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