Update 17/02/2011

Well it's been a while since I've updated on this project. I'm working on so many different things that it's hard to keep it up to date.


I will be posting an updated version of the Spec. list (as below) soon to give an Idea of the revisions I have made up until now.

Hardware Modules

Output

Plug Block Switching

• 1 to 41 UK sockets (230 V ± 10% at 50 Hz) with a maximum power rating, to be confirmed, allowing for the switching on and off of light bulbs, fans or anything that does not exceed the power rating

• These will be designed for low-frequency switching e.g. on for 12 hours off for 12 hours

• They will also be able to be set to turn on/off at a certain temperature, but will not thermostatically control devices as such devices are not suitable for high-frequency switching

 Thermo-controlled Plug Block Switching

• 1 to 41 UK sockets (230 V ± 10% at 50 Hz) ) with a maximum power rating, to be confirmed, allowing for the thermostatic control of heat mats, ceramic heaters and heat rocks (not recommended2) that do not exceed the power rating
• These will be programmable to heat to certain user-defined temperatures (or ranges) as picked up by the digital temperature probes
• They will also allow for one temperature probe to control several, or all devices in the block or a combination of any available probes to control the available sockets (depending on model)

PWM Fan Control

• This optional module will allow for the control of PWM controllable fans or other PWM controllable devices (such as LEDs)
• This is a low power output that is powered by the system itself3

 Low Power Switching

• Another optional module allowing for the switching of devices like misters or waterfalls (or other small-motor driven devices)
• These can be 'programatically attached' to any thermometer or hydrometer

Input

Thermometer(s)

• These high precision digital thermometers (probes) will relay the temperature of its surroundings to the board at a high rate
• They will be protected by a waterproof housing

Hydrometer(s)

• These high precision hydrometers (probes) will relay the relative humidity of its surroundings to the board at a high rate
• They will be protected by a waterproof housing

Timer

• The timer4 will allow for accurate time keeping and thus timing of switching and data keeping
• This timer will be completely separate of the computer's clock

PC Link (Serial Comms)

• The serial PC Link (USB) will allow for:
• data to be transferred between the system and a computer
• settings to be programmed into the system
• the system firmware to be updated
• This link will not need to be connected to a computer all the time unless:
• large quantities of data are to be stored for data-logging
• data from a network is required
  

1 Preliminary design parameter

2 Heat rocks have been reported to be dangerous

3 Requires connections to be wired into the system requiring some knowledge

4 An in-built function of the system

All content Copyright © Ben Duncan 2011

Hardware Block Diagram

First Update

This is what I have posted on the RFUK forum lately. I will be updating the forum and this blog regularly as the project develops.


Update:

OK so progress has been slow due to concentration on Uni work and reptile care (mostly the playing part :P ).

But I've looked into this in more depth and am starting the design of the application that will interface the hardware with a computer. There will be two options for the software.

• Complete time-line control of the system, meaning the computer must be on at all times.
• Board setup interface and data-retrieving.

The first would mean that the computer would send commands to the control board and retrieve live sampling data for the computer to save in a database (datalog). The board itself will have power and the basic functions to keep the system running the basics if the computer fails as a safety feature.

The second 'mode' would allow for the computer software to 'program' the board with settings that you specify using the UI (user interface). This means non of those horrible button click menus used on digital thermostats and similar.

I will also be drawing up some Ideas for some different versions of the hardware soon. Such as different output/input configurations, power specifications, waterproof or not, and other spec. models.

This is just a start and I hope to keep you all updated as much as I can.

Cheers for reading.

P.S. Please comment with any Ideas or helpful criticism as of yet