Open Source Thermostat and more (Schematics)

Cool, I'll add it to my hardware links section of my pages. :-)

Thank you. The more people that add their feedback will make these projects a reality. I'm working on more content to describe operation and adding one more really simple (but pretty neat IMHO) remote temperature sensor RS485 of course.

I came across ages ago a very simple RS485 to RS232 using only 2 1.2K resistors! It was very basic but it worked, I've lost the schematics ages ago. Elektor or Circuit Cellar maybe.

Bill

You should check the HCS II project, it uses several 8031 boards and PIC boards. The one thing you really lack is software.

I don't remember seeing anything like that in Circuit Cellar. I have my doubts that it would work for bidirectional communication. Isn't RS485 a + and - signal? I wonder if that was for sniffing the RS485.

I'll have to check my back issues of epe & elektor, the 2 resistor RS232 to 485 did indeed exist, it couldn't handle devices with termination or long lines but was a cheap & cheerful way to talk from your PC to a RS485 deivice.

I have all those HCS II issues and what I would like is to give my linux server the eyes and ears it needs. I have ICE pods for the

16F876 and 16F628 & 509 and will use an ICD2 for the 16F87 & 18F2525 series.

I do remember seeing lots of CEBUS stuff back then too and a little modbus.

PS two more devices will be posted in today or tomorrow. Then it's on to firmware.

New will be (names may change :-)

Owl: (a very inexpensive networked low power temperature sensor) Basically a LM75 I2C temperature sensor, RS485, PIC12C508, 32khz crystal, 3 bit address switch. The fun part, it's SLOW 300baud and automatic, device 0 transmits every 4 minutes, all other devices will sync up and send their temperature reading 4 seconds+address after the master (00) sends. It's designed to have it's own network and will work with any operating system. Updated firmware and or flash PICs will allow more operating modes in the future and new RS485 chips more devices per network ~128

Fiddler & Crab: (4 switch inputs, RS485 or RS232) Fiddler = 4 relays probably aromat PA series Crab = an L298 dual motor controller CPU 16F87 or 16F628 should work with both, trick will be one circuit board for both.

Bill

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 PIC)

Bill

Something I'd like to do with the schematics on

Looks great IMO.

Bill