Help on an idea please! Relays etc

I need to create a project where i take my arduino mega and read a temperature from a probe. then based on the temperature turn on a lamp to adjust to a set temperature.

IE keeping the temperature set to a say 85 degrees.

Im totally new to this. the probe could do with being water proof and maybe have a display and either buttons on it to adjust the temp. Ive seen the relay shields that have 4 relays on them and this could be useful to use as i may want to replicate the process on 4 differnt ones at 4 different temps. Im in the UK so must be able to use 240v and im likely to be using a standard 100w light bulb in the lamp.

Please can anyone point me in the right way or guide me to look at the right place.



im likely to be using a standard 100w light bulb

I don't think you can buy such a thing, can you?

Awol, I've always assumed that the light bulb regulations in the UK would be avoidable, in that there are some environments (e.g. machine shop) where incandescents are desirable or necessary. Some legacy equipment such as incubators would need them too. I was expecting that you'd still be able to get them but they would command a price premium that'll likely rise over time. I have no hard data - is the change really so draconian?

why not, AWOL? at least in europe you can still find them...


anyway, it doesnt not sound like you need a mega, you'll probably be fine with a uno or duemillenove ...

places to start searching for parts might be or (not saying you should necesarily buy them there, but look at what they have in stock, to get an impression of what is available...)

theres a guy who posts in this forum quite a bit who recently started his own shop, you may want to check it out as well:

Also try googling liquidware, as far as I remember they had a nice temperature sensor...


what are you building? a greenhouse?

if you have questions to any specific product you can allways come back here and ask about compatability etc.



why not, AWOL? at least in europe you can still find them

They're getting rarer, because their manufacture or import has been banned in the EU since 2009.

yeah, I know... (granted I am in canada at the moment) but, I have not noticed any effect - at least 6 months ago in the netherlands getting regular bulbs was no problem... ...the day when we run out will make me sad :-(

Theres always the heat lamp, probably slightly more efficient at producing heat than an incandescent lamp :

The easist way of controlling it (or a 100W bulb) with an Arduino is probably a small SSR :

in the netherlands getting regular bulbs was no problem

Yes, the Dutch are famous for their bulbs.