Open Source Thermostat and more (Schematics)

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I've just put up a very basic (schematics only at this time) site.
There are currently four projects:

    Cricket Communicating Thermostat (IR, iButton, RS232 or 485)

    Ladybug Super IO Controller  (RS232 & RS485, RTCC with 24hr backup,
relays, 3 digital & 1 digital/analog input, 1 iButton)

    Daisy Communicating Clock (six digit RS485)

and just for fun Dice

All are PIC Microcontroller based, some are configurable at build time.

Example: Cricket will work stand alone (1 relay) or mate with Ladybug
relays) similar hookup to an RCS type thermostat.
Ladybug can be standalone similar to an Elk Magic 443, but with more
both RS232 & RS485 and a RTCC as standard. Can be upgraded to 32K when
a PIC 18F2525 instead of the standard 16F876

Also all (except the dice) can be reflashed via the serial port
and the Ladybug supports ICD/ICP

I'm looking for ideas, advice etc...  I want to make open source home
automation products for anyone to afford & use.  Also any help would be



Re: Open Source Thermostat and more (Schematics)

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I think you've got that the wrong way round.  The Daisy and Cricket both
show a 16F628 PIC which can't use a bootloader to self program the FLASH,
they can do LVP/ICSP. It's the 16F876 that can do both.

I'm also intrigued how the key switches work on the same two schematics
since the key scan diodes will pull the input low when a key is pressed, but
there is nothing pulling the RA5/MCLR pin high. Have I missed something?


Re: Open Source Thermostat and more (Schematics)

Thank you Pete, I'll correct the schematics in both and repost. My
tech-tools emulator has  a weak pullup on MCLR I forgot to include in
the schematic.

I'll also use the PIC 16F87 in Cricket, I've found several bootloaders
for that one.

I wanted to get feedback like yours before commiting to PCBs.  I'm also
trying to find a better way than using a opto isolator for power loss.

PS the display in the Cricket uses a method called Charlieplexing


Re: Open Source Thermostat and more (Schematics)

I've added two more schematics to the page, I've put Fiddler Crab on
hold while I write up descriptions on the six projects on the site.

The added schematics include:

Owl a iButton / 1wire security system (simple to show what can be done
with a 8 pin PIC)

Beetle (low cost) addressable remote temperature sensor (another 8 pin


Re: Open Source Thermostat and more (Schematics)

Something I'd like to do with the schematics on

Looks great IMO.


Re: Open Source Thermostat and more (Schematics)

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Interesting that the jack screws on the D-connector on the first 3-D PCB
view have left-hand threads. ;)

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