Building a steam detector

Hello I have an UNO and would like to build a steam detector with an out put on a timer.
So when I take a shower a steam sensor detects steam and would then send an output to a relay (ssr 240vac) on a timer for say 10 minutes.

A simple device with 1 input device and 1 output command.

Can anyone help with schematics and code?

The first thing you need to tell us is what sensor you propose to use to detect steam. My guess is that it is not a simple thing to do.

Programming for a time interval is straightforward.

...R

I think there are easier ways to detect whether someone is having a shower, such as a water flow detector mounted in the shower hose.

If all you want to do is have this trigger a relay for a certain amount of time (which probably doesn't even have to be that accurate), you can do this much cheaper and smaller by using a 555 timer in monostable mode. An Arduino is total overkill for such a project.

I would try DHT22 if it can detect "steam" from shower by quick increase of humidity and possibly temperature too. I think Arduino + DHT22 is still cheaper than water flow detector + 555. But lot of work is needed for both if OP has no experience (it is likely: first post here). Doable but you need to start blinking LEDs and doing such "basic stuff". Also note water + 240VAC KILLS! You MUST know what you are doing before you try to do this.

I'd use a BME280 sensor and turn the fan on when humidity exceeds 95% or some other value determined by experiment.

I don't recall the OP mentioning a fan. I have been assuming he wants to warn the user that he has been showering for 10 minutes and it is time to stop.

I have no experience of any humidity sensor but I wonder how long it takes them to realize that the first person has finished his/her shower and that a second person is now using it and a second, quite separate, 10 minute interval needs to be timed?

...R

Humidity sensors are quite slow (in the tune of several minutes) to react to large changes in humidity, like you would have here. So it'll take a few minutes from start of showering for the sensor to react. Also those sensors must be kept away from water, just vapour. Condensation may also be a problem, and that's a real issue in a shower where the air is easily over saturated, and clouds tend to form (often the air in the room just outside the shower cubicle is a bit cooler than the air inside the shower, which is heated by the water).

OP didn't state what the relay is to switch (I would also assume a fan, but could be something else of course).

OP also didn't state whether the 10 minutes should start when the shower is turned on, or when the shower is turned off.

So let's wait for OP to come back and clarify what they want and what they think of the proposed solutions.

How about temperature?

Strap a temp sensor to the pipe on the shower head, should be around 70 degrees F to start and something over 95 F when the water is warmed up to shower temp. Temperature is cheap and easy

saildude:
How about temperature?

Strap a temp sensor to the pipe on the shower head, should be around 70 degrees F to start and something over 95 F when the water is warmed up to shower temp. Temperature is cheap and easy

Nice idea but it won't be so precise.
If the ambient temperature is also high it won't be a big difference between it and the water temperature so no stream will be created and then triggering the fan or whatever for no reason.
Same as for a low temperature in the ambient when as much as 25 degrees C water can form stream, and because the limit of the water is higher it won't trigger the output when needed

Maybe using 2 temperature sensor will reduce the false triggers by estimating the stream.

prologikus:
If the ambient temperature is also high it won't be a big difference between it and the water temperature so no stream will be created and then triggering the fan or whatever for no reason.

The ambient temperature high enough to make steam? I think everyone in the house would be dead at that point.

wvmarle:
Humidity sensors are quite slow (in the tune of several minutes) to react to large changes in humidity, like you would have here.

So you've never used a BME280 then? It's so fast that the datasheet claims it can be used for indoor navigation just by identifying the humidity changes when you move from room to room.

It's response to a humid breath is pretty much instant. It doesn't pick up on the temperature change from a breath until many seconds later.

MorganS:
So you've never used a BME280 then?

Not yet indeed, it's on my wish list. Not for the response time, but for the integration with pressure and air temperature.

aarg:
The ambient temperature high enough to make steam? I think everyone in the house would be dead at that point.

No, he said the opposite: ambient too high for the shower to produce steam, so no steam at all.
That's for me also quite normal, no steam produced in summer (ambient 30-33 C, usually showering "cold" which is about the same temperature - even if showering with water at 38 C there's no steam production). Detecting showering with humidity detection is also getting tricky as the baseline ambient is often at 90% or so.