Temperature control of a small water tank

Kits PC Related Projects
1

Hi there,

I have a question about a project I am planning to start working on.

To put it simply, I want to control the temperature of water in a small vessel, somewhere between 30 and 100 degrees celsius. (different temperature/time combinations for different experiments)

I am planning to do this with a K8055 USB interface board.
I plan on heating the water with a basic 220V 1000W heating element (like you find in a domestic water cooker).
For now, let’s assume that I use a relay to control the heater (in fact I am not sure if the result are “smooth” enough or will result in a large sawtooth, but that is a separate issue)

I have seen a K8067 kit, which has a range from 0 to 70C. Is it possible to adjust this to 0-100C??
Moreover, is it suitable to make submersible, or are there other/better possibilities?

Kind regards,

2

It is not possible to adapt the K8067 for 100°C. Furthermore, it is not submersible.
Sorry, we do not carry a suitable sensor.

3

wow you have managed to crush all my hope in one reply…

I know it is not submersible… I think I have found some info on how to make a probe with a LM in it (homebrewtalk.com/f51/diy-sub … obe-26400/)

Isn’t there a way to modify the temperature range of the K8067 with another LM?

4

As I understand from the assembly manual and the the datasheets:
Sensor LM335 is a temperature sensor with a range of 0-100C (national.com/mpf/LM/LM335.html#Overview)
Voltage reference LM385-2.5 has a range of 0-70C (national.com/mpf/LM/LM385-2.5.html#Overview)

What is the function of the LM385-2.5?
Is it only used as a reference temperature (i.e. the ambient temperature?)

The sensor itself seems suitable to operate in a 0-100C range, so why can’t the kit operate in that range?

5

No suggestions anyone?

6

In no way we can assist with modifications.
Please note that the LM335 sensor can measure up to 100°C.
Using it at 100°C is just too close to the max. operating range.

7

Hello soccie49

Maybe you can use a temperature sensor from a car or a motor. They usually have a range to 140 degrees Celsius. Most of them are NTC resistors. When heating them the resistance will decrease.
When you add a serial resistor and connect them to a 9 Volt battery, you can use the voltage over the NTC for measuring the temperature.
You can use analogue input A1 to calculate the temperature.

I hope it can solve your problem.