Water flow sensor and temperature sensor in water

Hello my name is Christoffer and i'm new here and new with Arduino.
Does any of you guys know if theres a water flow sensor that works on Arduino ( I expect the flow to be around 2 L/m - 15 L/m and the temperatur to be around 0-80 C°).

I am also looking for a temperatur sensor which works in water. Does any of the temperatur sensors here on this website work in water or do you know of any that does and works with Arduino ( I expect the temperatur to be around 0-80 C°)

what kind of timer do you need, if you want to display the volumen of water going through the flow meter, in Liters?

Really hope you will and can help me.

best regards Christoffer.

I can't think of any sensor that works "in water"... you will always be looking at a sensor somehow packaged in a waterproof "container".... so why not just leave the water inside its pipes, but give the heat a way to reach the sensor?

A length of copper pipe somewhere in the plumbing with any of the usual sensors... the DS18B20 is excellent... slight learning curve to get started, but not much, and well worth it... taped to the pipe, and then something wrapped around that the keep the heat in, and you are done.

OR.... if you want to "dip" the sensor into, say, a tank... make a big "test tube" out of copper pipe or similar, put the sensor in a small ball of steel wool (to "connect" the sensor to the sides of the "test tube"... only just enough to do the job, and beware shorting the connections to the sensor), and push that down to the bottom of the "test tube". Be careful that any silicone sealer you use to make the thing waterproof doesn't get between sensor and "test tube" walls.

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Flow sensors...

All the ones I am aware of are SUITABLE for a given range of flow, given in gallons or liters per minute, per hour, etc.... but (until you get to expensive integrated things) REPORT the passing of a certain volume... a gallon, a liter, a cc. It is up to you, in software, to count how many units of volume have passed in a given stretch of time, and then express that as L/min or whatever you want to use. (Not hard.)

There's a wonderful collection of animated diagrams covering more flow sensing technologies than the whole forum could imaging in ten years at....

... but prices... ouch! Go to eBay, unless this is for "the day job"! An eBAy search on "water flow meter" will give you lots of options.

Thermocouples can be interfaced to the Ardu' : Thermocouple sensor tutorial

I'm sure that you can get a thermocouple that would be waterproof because it's just a case of making a tube of one metal with a wire of another welded to the bottom.

From a random e-bay listing:

K-Type Thermocouple probe lead

In Bean tips

Ideal for air and liquid probe

Yellow standard K type connector

For digital thermometer

Support range from -50 °C to 200 °C

Cable lead around 100 cm long

Here's a pre-waterproofed version of the DS18B20 http://www.adafruit.com/products/381.

As to timers, you can just use the millis function - no need for external hardware.