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Topic: NEEDED CODING TO CONTROL A PUMP WITH INPUTS FROM TEMPERATURE AND HUMIDITY SENSOR (Read 1 time) previous topic - next topic

abhisheksingh9

HELLO EVERYONE

I NEEDED CODE TO TURN ON/ OFF A 12V(.5A) D.C. PUMP WHEN TEMPERATURE AND HUMIDITY VALUES REACH A TARGET VALUE. THE TEMPERATURE SENSOR IS MLX 90614 IR TEMP. SENSOR. THE humidity sensor is  Hr202 Humidity Module. the microcontroller is arduino uno.

i will pay 50% once code gets completed and 50% when it works succesfully with my sensors.

robtillaart

50% of how much?

what are the threshold values to start?
what are the threshold values to stop the pump.

The pump can be controlled by a relay or a power transistor.
Do not forget to put a diode over the relay (google images is your friend)

Rob Tillaart

Nederlandse sectie - http://arduino.cc/forum/index.php/board,77.0.html -
(Please do not PM for private consultancy)

PaulMurrayCbr

What are your target values?

You have two numbers in, and you control one pump. Should the pump come on when either value exceeds a target? When both values exceed a target? When some function of the two values exceeds a target?

What kind of hysteresis would be suitable? You don't want the pump rapidly switching on and off when the temperature and humidity are very close to the target. Should it be based on the values, or did you want something time-based?

Did you want the values to be adjustable?

Did you want some sort of override switch, so that the pump could be manually turned on or off? Did you want any sort of indicator LEDs?

Are you able to edit the values in a sketch yourself, to tune them to what you need? Are you comfortable with compiling a sketch and uploading it onto an arduino? Do you realise that what you will get is some code that you need to compile and upload? Or where you expecting that someone would supply you with a board with the sketch loaded onto it?

Your MLX90614 uses SMBus, which is mostly compatible with I2C, and your Hr202 is an analog input.

Your coder will almost certainly need to work with an actual MLX90614 to be sure the code is talking to it correctly. So he or she will need to source one of these things, which will take a little time and a few bucks. Is this ok? If you need this job done in a very tight time frame, then it might not be do-able.

The humidity sensor is trickier - it will need a voltage divider circuit (same as using a potentiometer). Do you already know what voltage divider values you will be using, and the target numbers on the analog input? Or will your coder need to work it out from the data sheet?

(EDIT) The data sheet is here: http://www.elecrow.com/download/HR202%20Humidity%20Sensor.pdf . The resistance of the humidity sensor is dependent on both the relative humidity and the temperature. Determining how to convert the value off it into the decision you want the code to make is not trivial.

Is operating your motor simply a matter (from a programming point of view) of setting a digital output to HIGH or LOW? It looks like it is - I assume you are using some sort of motor shield. Bit it doesn't hurt to ask.

When did you want this by?

And, of course, what's it worth to you?
http://paulmurraycbr.github.io/ArduinoTheOOWay.html

DuaneDegn

I tried to get clarification on the details in this thread.

I still don't understand how pumping cold water alone will regulate humidity while maintaining a temperature.

cedarlakeinstruments

Relative humidity is also a function of temperature, so that may be what he means.
Electronics and firmware/software design and assistance. No project too small

DuaneDegn

Relative humidity is also a function of temperature, so that may be what he means.
Except cooling the air will increase the relative humidity. In the other thread he said this:

my application is for room coolers in order to reduce the humidity transmitted during its operation in summers.
Cooling the air with cold water can remove moisture from the air. In order for moisture to be removed, the air needs to be cold enough to cause the relative humidity (RH) to reach 100%. At this point the moisture will precipitate/condense from the air and it can be collected as liquid water. If one knows the (RH) and temperature of the warm air, the temperature which will cause the moisture to condense out can be calculated/looked up. I'm pretty sure the temperature where the water begins to condense out of the air is called the dew point.

Once the the moisture has been condensed from the air, the air will still be cold. If the room's temperature is to be maintained, then this air needs to be warmed back up. I believe commercial dehumidifiers use a heat exchange system so the incoming warm moist air can warm the outgoing cold dry air.

I still don't understand how the OP wants to regulate moisture while maintaining a constant temperature using cold water alone.

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