Build a Digital Timer for a water heater or larger appliance

This 'digital timer' project is very cheap - you can find an amazing completely programmable digital wall timer for $25 on Amazon, or same price in Home Depot.

I want to play with Arduino since I'm a Computer Science major (Neuroscience as well), and I have been learning about this stuff in my Digital Electronics II class.

We are using Prototyping boards, writing code, and then demonstrating the project.

But I want to experiment with Arduino and a good project to start would be a small on-off digital timer.

I know this is possible, but is an Arduino something to use for this project? I would need a relay module or something to handle a large water heater. Would this work? I saw people use Arduino's for a greenhouse, and he could open the screens based on the temperature, sunlight, etc. So this is essentially high amperage like a water heater.

I guess my question is, would it work? Also, what would I need? Is a Relay Module enough to power this high amperage? OR, use a relay module to control a larger relay or breaker? Right now, the water heater is direct to the breaker panel, and at a breaker switch.

Maybe this is a project for a simple $25 digital timer. :(

I'd like to have an override switch (HTML web page is okay) and then on a daily timer, easily configuring the days, etc. The honeywell digital timer can do all of this, and is quite small.

Hopefully I can find helpful advice.

Any arduino + any relayshield would do the job. Probably for even less money than a honeywell.

You may also want to use a RTC (Realtime clock) module with this, as although the Arduino clock is relatively accurate, i.e error is only normally a few seconds per day, if your project is a timer then I guess accurate time is important

you might add a temperature sensor to detect 100C to stop cooking in time.

You sound a bit ambivalent about your goals. If you want to learn to use an arduino doing this project, it's quite feasible. If on the other hand, you just want a timer at a low cost, you're best served pointing your browser at Amazon. You will struggle to beat the price you quoted from Honeywell, particularly if you want the arduino to have network connectivity to serve up a web page for the override.

There are of course other things you can do with the arduino that aren't competing on price with the economies of scale that huge manufacturers enjoy - something more custom. The greenhouse controller you mention is one, lots of people lately seem to be working on Acquarium controllers. Take a look at for a use of arduino to save money on power bills.