timer

Temperature sensors. What year technology do you prefer?

Do you want to change the tempo as well?

A thermostat would be the easiest design. They even have more advanced programmable thermostats available. If you are designing an electrical circuit, a window comparator would give you the logic required to measure an analog temp sensor.

It helps to know the power requirements, what you are controlling based upon temp, and what you are measuring the temperature of. More details are always better.

A thermostat might work but an aquastat most certainly will.

Most every furnace that supplies domestic hot water has two seperate settings on the main controls. Typically the adjustments are bimetallic adjusters working with relays and are found right at or inside the furnace.

One limits how high a the water temperature gets and a second keeps the water from falling below a certainly limit. They are quite common and should be easily adopted to do what you ask.

L.J.

Hi Solar,

To spend your time in designing, modification or alteration, on your problem if the thermostat is available then that is the simplest temporary remedy. timer will work however you will be encountering some problems like in-accurate temperature due to the number of door opening when people coming in and out. timer only useful if you desired to shut the unit off during the night if the desired temperature is already reach and no one will open it until the next morning. at the end of the day my suggestion after doing temporary remedy "go and order the proper replacement microprocessor, etc." which you detected to be defective.

Kind regards

Roman

Use a PIC circuit with either a thermister or dedicated temperature sensor. Picaxe.com have circuit boards already set up to monitor temp and turn on outputs so its relatively easy to do this and report back to a PC info such as how long it was on for. Download and read the free docs. Cost probably less than £20.

Depends on WHAT you want to start. If that means, switching a more power needing device on and off then a thermostat capable of current switching may be the solution.

If you only want to trigger a process and need a, lets say, TTL-Signal, then there are ready-to-use temp-sensors with built in reference and comparator giving you a logical signal depending on HI-LO-Temp thresholds.

there are several Data Logger with switch circuits that can be programmed to do what you need. they are pretty expensive. they can do so much more and are very versatile. if you planing to do a lot different experiments. it might be worth it.