Hi, Mathias from Denmark here.

I am automating a chicken coop mostly build on old Lego Mindstorms components (controlling the door opening with light sensors, self controlled feeder etc). Now it's winter here and the water supply to said chickens are freezing over. Rather than buying a "heater plaque for chicken water dispensers" I want to build my own running on DC voltage from the Lego unit (9 volts output). I am not limited with batteries as it is all plugged into to a power supply, but I want to run the heater element on the Lego 9v system, such that I can make it an integrated part of the automated system.

Any thoughts apart from what has already been described in this excellent tread?

Mathias
Legochicken.tumblr.com

 

This probably should get its own thread.

Keeping water warm requires heat, and that means you are ultimately limited by the weakest link in your system. By "weakest" I mean "least able to handle current and/or power". I suspect this would be your power supply. You do not want to run your supply at more than, say, 2/3 of rated power for too long.

Once you know how much slack power you have, I'd be tempted to just use light bulbs for heaters, and mount the bulbs under the water supply, with insulation around them and the water reservoir to help contain the heat. A small recirculation pump would be something to consider, even if it only runs intermittently.

 

It probably should have a new thread, yes sorry about that. Thanks for your reply. I now have a working prototype. Photo of parts of it here: http://www.flickr.com/photos/matisok/8259505564/in/photostream and a video here http://www.youtube.com/watch?v=5Y0983FZkWg

 

Voilà! Your own thread. Tell me if the title is of your liking.

 

I don't see any problems. Is there sometning you wanted to ask about?