Silicone Heater Mats - Homemade Thermal Chamber. - Page 1
Forum section: electronics / beginners

author: Stephenniall
author_rank: Contributor
timestamp: December 21, 2012, 01:51:09 am
content: Hi guys,After watching Dave's video on his Thermal Chamber, I've decided to build one. Instead of using the peltiers which his device used, i've decided to try and use the silicone heat mats i recycled out of something I took apart a while ago.They are like the ones pictured above (Rectangle) - They are powered by 240v, When plugged straight into the mains supply they heat up to over 120 degrees (Rough guess, no proper measurement will be done till my IR Thermometer gets here).I'm guessing the way to vary the temperature of these is to change the voltage supplied ? Is there a simple way to do that.If that isn't possible, Another way i was thinking is to use an arduino board, With a solid state relay, to turn the mats on and off to get it to a desired temperature.Does anyone have any input or suggestions as to help me with this idea ?All help will be appreciated.Many Thanks,Stephen

author: ftransform
author_rank: Frequent Contributor
timestamp: December 21, 2012, 06:01:10 am
content: They might put out noise if they are powered by strait AC.Could you run smoothed DC through them instead?

author: phil4107
author_rank: Newbie
timestamp: December 21, 2012, 06:25:25 am
content: The easiest way to alter the voltage would be to use a variac, though I'm not sure how that would fit in with your design.

author: IanB
author_rank: Super Contributor
timestamp: December 21, 2012, 06:37:09 am
content: The easiest and simplest way to vary the power supplied to a heater is to use a light dimmer circuit. Using such a circuit it is also possible to vary the power electronically so that a temperature sensor can be used to measure the temperature and a control circuit can vary the power to regulate the temperature.

author: Balaur
author_rank: Unknown
timestamp: December 21, 2012, 09:33:58 am
content: We're using piles of such things at work.Frankly, while you can roll your own solution, I highly recommend using a commercial PID controller. You can buy them on eBay for as low as 10 euros (if you feel adventurous) or a bit more (30 euros) from online stores, hopefully less expensive than an Arduino plus relay, sensor or whatever.Cheers,Dan

author: Stephenniall
author_rank: Contributor
timestamp: December 21, 2012, 04:28:05 pm
content: Thanks for the reply guys.Ftransform - I'm not sure about running Smoothed DC Through them, It wouldn't be too hard to do, Although i don't think it would give me better results.Phil4107 - I was thinking that, Although i don't have a Variac, and they go for silly prices where i live !IanB - I never thought of that, That could definetly be something i look into as its cheap & would be effective.Balaur - Thats probably the easiest way, I didn't know such things were available so cheaply ! Most probably the method i will use, I'll probably test it with the light dimmer as Ian suggested, just to test if i can get up to the temperatures i need too, Then if my design is good enough, i shall buy one of these !Thanks alot for all the suggestions.Many thanks,Stephen

author: jeroen74
author_rank: Frequent Contributor
timestamp: December 21, 2012, 08:57:33 pm
content: Aren't these pads meant to heat things mainly by conduction? A thermal chamber usually uses convection (e.g. heater coil and a fan). I don't see these pads heat up some widget by any significant amount. Apart of the 'thermal mode' they are quite low power too. Maybe a couple of tens of watts at most.