the old fart
Senior Member
double posted,
Please see below.
Please see below.
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Room Thermostat
- Thread starter the old fart
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the old fart
Senior Member
I have put together a room thermostat.
1" LED display, controlled from SA1064 chip.
20X2 picaxe controller.
Base default temperature is 18 C. rises to 21 C at pre defined times.
Panel controls can set 18C, 21C, or +- steps of 0.1C.
Voltage free contacts for control of zone valve/ boiler.
OLED display plugs into control box for setup / time set. (2.5mm stereo plug)
12v power plugs into control box, 7805 regulator added.
Programming lead, plugs into control box, (3.5mm stereo plug)
I'm still experimenting as to where to place the DB1820 sensor.
Can also be adjusted using a remote I/R handset. for setting temperature and time.
See here for the excellent tutorial by westaust55,
http://www.picaxeforum.co.uk/showthread.php?22252-Getting-Started-with-the-SAA1064-i2c-bus-4-Digit-7-Segment-LED-driver-chip&highlight=sa1064
Word/Byte/Bit table
Program listing
View attachment Thermostat.bas
I'd post the listing but it exceeds the 10000 character limit.
230vac relay box on top, control box below, plugs right hand side.
View attachment 15345
Control panel, top right I/R receiver.
top left DB1820 sensor, mistake putting it here.
Manual buttons at base.
(tried touch pads, but faceplate too thick, and 20X2 doesn't support 'touch')
View attachment 15346
1" LED display, controlled from SA1064 chip.
20X2 picaxe controller.
Base default temperature is 18 C. rises to 21 C at pre defined times.
Panel controls can set 18C, 21C, or +- steps of 0.1C.
Voltage free contacts for control of zone valve/ boiler.
OLED display plugs into control box for setup / time set. (2.5mm stereo plug)
12v power plugs into control box, 7805 regulator added.
Programming lead, plugs into control box, (3.5mm stereo plug)
I'm still experimenting as to where to place the DB1820 sensor.
Can also be adjusted using a remote I/R handset. for setting temperature and time.
See here for the excellent tutorial by westaust55,
http://www.picaxeforum.co.uk/showthread.php?22252-Getting-Started-with-the-SAA1064-i2c-bus-4-Digit-7-Segment-LED-driver-chip&highlight=sa1064
Word/Byte/Bit table
Program listing
View attachment Thermostat.bas
I'd post the listing but it exceeds the 10000 character limit.
230vac relay box on top, control box below, plugs right hand side.
View attachment 15345
Control panel, top right I/R receiver.
top left DB1820 sensor, mistake putting it here.
Manual buttons at base.
(tried touch pads, but faceplate too thick, and 20X2 doesn't support 'touch')
View attachment 15346
Last edited:
the old fart
Senior Member
Hi,
look here for the 7seg and driver chip,
http://www.picaxeforum.co.uk/showthread.php?22252-Getting-Started-with-the-SAA1064-i2c-bus-4-Digit-7-Segment-LED-driver-chip&highlight=sa1064
Look in the manual for the I/R receiver and the temperature sensor connections
Refer to the Word/Byte/Bit table for connections to the picaxe.
The rtc/eeprom is the cheepo DS1307 RTC AT24C32 board, hence the time correction routine. Tried different crystal but it only made timing worse.
I used the pcb as supplied by the PICAXE shop.
remember that temperature / piezo /IR are connected direct to the picaxe and not via the uln2803, or pulldown resistors.
My setup has been working without problem for over a week.
Dave