PIC Weather Processor
This project is a board to go between the Peet Brother's U-2000 Weather Station, and a
TNC. There are several reasons why I see the need for such a board:
This board is designed to go between the weather station and the tnc, taking the
place of the usual RJ-11 to DB-25 interface cable. The PIC processor decodes the
incoming records in complete record format, and parses out the significant data fields.
The data and time are included in the data, which allows the PIC to send out the APRS
weather packets. The interval between packets is specified with a DIP switch.
- The new "Complete Record Format" from Peet Brothers is more than 400 bytes long.
This makes it too long to be used in a stand-alone weather station. While the old
format is still available in the U-2000, the Peet Brother's Weather Picture requires
the complete format. I want to be able to run a stand-alone weather station and the
Weather Picture simultaneously.
- While some U-2000's (though not all) include a 5 minute wind gust as part of the
stand-alone string, it is only for the last 5 minutes. If the transmit interval
is set to more than 5 minutes, some of the wind gusts will be missed.
- In stand-alone mode, the U-2000 puts out total rainfall since it was last reset.
There is no provision for 1 hour or 24 hour rainfall.
More to come...
- Yes, this can be modified to make the Radio Shack Weather Station function as a
stand-alone wx station.
- Yes, I will probably do the Radio Shack version, though I'd welcome someone else's
participation. It has taken me a month to go from not knowing anything about PICs to
producing this project...it isn't hard. The code I have
is written in PIC-C, $99 from http://www.ccsinfo.com.
A free Windows development environment (MPLab)
including assembler for the PIC is available from
http://www.microchip.com. I'll give my source code
to anyone that wants to try...there isn't much to it, the reason
I'm not posting it because there are a couple bugs I'm chasing down.
The tough part is fitting it all into
the 1024 instruction limit of the 16F84.
- No, the U-II version is not so simple. Both the U-2000 and Radio Shack send date and
time information as part of the data. I use this data to time the outgoing packets and to
fill in the date and time fields in the APRS packet. Since the U-II does not send this
info, a version for the U-II would require an outboard real-time clock, and a way to set it...
too much for this project.
- No, a printed circuit board is not available. If someone wants to take this task on,
I'd love to buy 10!
- No, I won't build you one, unless you are willing to pay my usual hourly rate...if you
have to ask you cannot afford it! It only takes an hour or two to build, and perhaps $15 in
parts from DigiKey. One of these days I'll put a part
- If you want a programmed PIC, either send me $10, or mail me a 16F84 and a return
paid envelope, and I'll program
it for you for free. I can also send you the hex file if you have access to a programmer.
Pictures of the prototype:
Schematic (forgive the low quality artwork!)
Mail comments to firstname.lastname@example.org
Steve's home page