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kr1st
03-08-2003, 04:10 AM
GPS support for Cybiko UI Messenger

A while ago I posted an article here about the software that I write for the Cybiko. The Cybiko is a small handheld computer that's just a little bit larger than a PDA and contains a 900MHz digital transceiver. It was designed for teenagers to play video games and "chat" with others who have Cybikos. Cybikos can often be found on sites like Ebay for about $10.

The UI Messenger software I developed turns the Cybiko into an APRS client when used with a KISS mode TNC and a 2 meter transceiver (HT). It allows you to monitor and log traffic on your local APRS network, send and receive messages, display yourself and other stations on a map and of course it can transmit your position. Another program, UI Gate, can be used to share one TNC and radio combination with many other Cybikos. It acts as a gateway between the 900 MHz channel, on which the Cybikos communicate with each other, and your local APRS network.

I've received very good feedback on my first article, which I appreciate very much. Now it is time to introduce a new version which supports the use of a GPS receiver. You can connect a GPS receiver to a Cybiko running the UI Messenger software and you will be able to see your position change on the map in real time. Any GPS receiver that can produce standard NMEA output will do. Most GPS receivers on the market today are capable of doing this.

<image src="http://www.kr1st.com/gpssup3.gif">

Unfortunately, you can not share the single serial port a Cybiko has between a TNC and a GPS, so you will need two Cybiko Classics to build a tracker. One Cybiko is connected to the GPS receiver and runs the UI Messenger software. The other Cybiko is connected to the TNC and runs the UI Gate software. UI Messenger can be put in and out of GPS mode on the fly and all functions normally offered by UI Messenger (mapping, monitoring of traffic, messaging etc.) will still be available when in GPS mode. In fact, you can now build one mobile installation and use that as your mobile and stationary (home) setup.

For instance, you could put a Cybiko/TNC/Transceiver combination in the trunk of your car and run the UI Gate software on that Cybiko. In the passenger cabin you use a second Cybiko running the UI Messenger software. Connect this Cybiko to a GPS receiver and put UI Messenger in GPS mode when you plan to be mobile. When you're at your destination, simply disconnect the GPS, turn off the GPS mode and take the Cybiko with you. You'll stay in touch with your local APRS network through the installation in the trunk.

The UI Messenger and UI Gate software with documentation in PDF format is available free of charge on my website at: http://www.kr1st.com.

73,
Alex (KR1ST)

kd7pfc
03-10-2003, 01:46 PM
Hay what about 6m?

Thomas KD7PFC KD7PFC@arrl.net http://www.qrz.com/iB_html/non-cgi/emoticons/biggrin.gif

kr1st
03-10-2003, 04:46 PM
</span><table border="0" align="center" width="95%" cellpadding="3" cellspacing="1"><tr><td>Quote (kd7pfc @ Mar. 10 2003,02:46)</td></tr><tr><td id="QUOTE">Hay what about 6m?

Thomas KD7PFC KD7PFC@arrl.net http://www.qrz.com/iB_html/non-cgi/emoticons/biggrin.gif[/QUOTE]<span id='postcolor'>
Hi Thomas,

Of course you can also use it on 6 meters. It doesn't have to be two meter FM.

73,
--Alex KR1ST

kg6pds
03-11-2003, 06:31 AM
So, whats the main reasoning behind having to use two of these devices instead of just one?

Wouldnt this kinda work like how the palm pilots are used with APRS? http://www.qrz.com/iB_html/non-cgi/emoticons/wink.gif

n0mhs
03-13-2003, 11:41 AM
</span><table border="0" align="center" width="95%" cellpadding="3" cellspacing="1"><tr><td>Quote (kg6pds @ Mar. 10 2003,23:31)</td></tr><tr><td id="QUOTE">So, whats the main reasoning behind having to use two of these devices instead of just one?[/QUOTE]<span id='postcolor'>
He actually explains why in the original post... since the cybiko only has one serial port, you have to connect two Cybikos up (via the Cybiko Part 15 data link) to get the required two serial ports (one for the GPS, and the other for the TNC).

- Stewart
http://groups.yahoo.com/group/MURS-OPEN
http://groups.yahoo.com/group/murslink

kr1st
03-13-2003, 02:28 PM
Indeed the Cybiko has only one serial port. Usually on computers and microcontrollers you can share a port when you use something like an HSP (Hardware Serial Port) cable which is basically a multiplexer which uses one of the serial port handshake lines to toggle between ports.

The Cybiko serial port does have one extra line, the RTS. However this line is hard wired to TxD and goes to a high state when data appears on the TxD line. Unfortunately, this is not controlled by the microcontroller (as it should) so that line can't be used to switch between multiple serial devices like a GPS and a TNC for instance. The documentation that comes with the software development kit does mention function calls to set and reset DSR, RTS, etc. but they are not implemented in the hardware.

73,
--Alex KR1ST