4 Channel Thermostat using PID loops

[malc-c]

Well a few months have passed and I'm able to get back to this project.

I used Eagle to design a PCB, but every time I ran the build it required a double layer PCB and my DIY PCB skills resulted in several coasters ! I've just found one of many stripboard design applications and have come up with the attached. Hopefully it won't need modding too much, and will either update the image when completed and tested, or confirm that I've got it right first time (be a miricle )

I'll also take some pictures of the unit as it's put together and will add them to this thread as I progress.

Note that before anyone jumps in and states that I need to break tracks around the relays, due to the lack of being able to design a custom component, I had to compromise, the real relay doesn't have all the pins on the package as shown

[malc-c]

Well due to work and other personal commitments I've been too busy to turn the drawing into a practical prototype... until today.

I called into Maplin and purchased some stripboard and a suitable box this morning and then spent an enjoyable afternoon building the board. I've not fully tested it yet, bit on powering up the EasyPIC board and taking a 5v supply and using a test LED, the pins to the LCD flashed the same way as they did on the development board (and there was no smoke )

Wife has plans to get me to sort out the garden tomorrow... but hopefully I'll find time to build the PSU board, and LCD and test this further before hooking up the mains to the relays. For convenience I'll probably take the sensors straight in through the back panel rather than rig up some connectors... we'll see.

It's taken me six months since DT (and Henrik) assisted me with developing the code to get this far. With out their help it would of taken me a lot longer. I'm determined to see this through to the end - I feel I owe it to you guys to prove the project works in the real world

[Mike, K8LH]

Hi Malcom,

A truly nice project Sir. May I ask if you've developed menu and display subsystems and would you have display examples you might share? Just curious to see how your user interface works.

Cheerful regards, Mike

[malc-c]

Hi Mike,

The menu's as they stand are fairly basic. If the option button is pressed the main menu is displayed.

LCDOUT $FE,2,"Main Menu"
lcdout $FE, $C0, "Select Option"

IF Option = 1 THEN lcdout $FE, $D4, "Set Time and Date  "
if option = 2 then lcdout $FE, $D4, "Set Night Period   "
if option = 3 then lcdout $FE, $D4, "Set Normal Temps   "
if option = 4 then lcdout $FE, $D4, "Set Lighting Period"
if option = 5 then lcdout $FE, $D4, "Run                "

Depending what state you leave the option button set to the LCD display reads

Main Menu
Select Option

Set Time and Date

The normal temp sub menu simply displays the A/D from the four pots.

The sub menu for the lighting period simply shows the time which gets changed by the +/- buttons so you can set the on time and then repeated for the off time (for each viv).

If I get chance I'll take some photo's of each menu and post them up at a later stage.

[malc-c]

Guys,

Normally when strip boarding I build as I build up the board from the schematic as I go along, and often test each section, ie get the LCD working, then the sensors, then the switches, then the RTC etc. However this time I used an application to design the board and having followed it found that the board contains an error somewhere as the LCD doesn't work. I'm no longer able to edit the post to remove the image so..

DO NOT USE THAT IMAGE

[mackrackit]

Sounds like one more reason not to use simulators and such.

I always thought, WOW!!!
Those folks that write simulators must really be good. Able to anticipate all variables and all....
Yeah right....

[Mike, K8LH]

Hi Malcom,

Thank you for the brief description of the user interface. It sounds very easy and very intuitive.

A couple more questions, please? (1) Do you "lock out" the pots' to prevent someone from accidentally bumping them and changing the settings? (2) Could you use a single pot' to adjust the four zones, one zone at a time?

Cheerful regards, Mike