RE: Arduino Starter Kit - Love Meter with faster Reset

genebren — Thu, 11 Jan 2018 14:43:56 GMT

It is fun to solve problems in software, but the truth here is that the problem exists in physics. The 'reset' time has more to do with the heat that you have applied to the sensor and the time it takes for that heat to dissipate. To speed up your reset time you could use a small fan to blow ambient air across the sensor. To do this you will need some code. While the temperature is near ambient the fan needs to be off. When the temperature is rising or holding the fan also needs to be off. When the temperature is above ambient and is falling then the fan is turned on. (Be careful to get a tiny fan that can be driven safely by the arduino and one that will no attack your fingers)

Have fun, but be safe.

RE: Arduino Starter Kit - Love Meter with faster Reset

mcb1 — Thu, 11 Jan 2018 02:51:52 GMT

They are addictive aren't they.

[embed:dc8ab71f-3b98-42d9-b0f6-e21e02a0f8e2:3ef06e6b-9b7d-4651-b12d-db8be7f5e991:type=c_cpp&text=%2F%2FLOVE+METER+WITH+FASTER+RESET.%0Aconst+int+sensorPin+%3D+A0%3Bconst+float+baselineTemp+%3D+22.0%3B%0Avoid+setup%28%29%7B+++Serial.begin%289600%29%3B+%0A++for%28int+pinNumber+%3D+2%3B+pinNumber%3C5%3B+pinNumber%2B%2B%29%7B+++++%0ApinMode%28pinNumber%2COUTPUT%29%3B++++%0A+digitalWrite%28pinNumber%2C+LOW%29%3B++%0A+%7D%0A%7D+%0Avoid+loop%28%29%7B++%0A+int+sensorVal+%3D+analogRead%28sensorPin%29%3B+++%0ASerial.print%28%22Sensor+Value%3A+%22%29%3B+++%0ASerial.print%28sensorVal%29%3B+++%0Afloat+voltage+%3D+%28sensorVal%2F1024.0%29+*+5.0%3B+++%0ASerial.print%28%22%2C+Volts%3A+%22%29%3B+++%0ASerial.print%28voltage%29%3B++%0ASerial.print%28%22%2C+degrees+C%3A+%22%29%3B++%0Afloat+temperature+%3D+%28voltage+-+.5%29+*+100%3B+++%0ASerial.println%28temperature%29%3B+++++%0Aif%28temperature+%3C+baselineTemp%29%7B+++++%0AdigitalWrite%282%2C+LOW%29%3B+++++%0AdigitalWrite%283%2C+LOW%29%3B+++++%0AdigitalWrite%284%2C+LOW%29%3B++%0A+%7D+++%0Aelse+if%28temperature+%3E%3D+baselineTemp%2B2.25+%26%26+temperature+%3C+baselineTemp%2B4%29%7B+++++%0AdigitalWrite%282%2C+HIGH%29%3B+++++%0AdigitalWrite%283%2C+LOW%29%3B+++++%0AdigitalWrite%284%2C+LOW%29%3B+++%7D+++%0Aelse+if%28temperature+%3E%3D+baselineTemp%2B4+%26%26+temperature+%3C+baselineTemp%2B6%29%7B+++++%0AdigitalWrite%282%2C+HIGH%29%3B+++++%0AdigitalWrite%283%2C+HIGH%29%3B+++++%0AdigitalWrite%284%2C+LOW%29%3B+++%7D+++%0Aelse+if%28temperature+%3E%3D+baselineTemp%2B6%29%7B+++++%0AdigitalWrite%282%2C+HIGH%29%3B+++++%0AdigitalWrite%283%2C+HIGH%29%3B+++++digitalWrite%284%2C+HIGH%29%3B+++%0A%7D+++%0Aelse+if%28temperature+%3E%3D+baselineTemp%2B2%29%7B+++++%0AdigitalWrite%282%2C+LOW%29%3B+++++%0AdigitalWrite%283%2C+LOW%29%3B+++++%0AdigitalWrite%284%2C+LOW%29%3B+++%0A%7D+++%0Adelay%28.25%29%3B+%0A%7D]

In your elseif statements, you are basically driving

Pin 2 = + 2.25 deg

Pin 3 = +4

Pin 4 =+ 6

You could seperate these into an if statement to just control that Pin based on the baseline +xx.

eg High is it's above or low if it isn't.

You could also do some averaging for achieving the baseline temperature, rather than the fixed 22 degs.

You could read the temperature 5 or 10 times during the setup and then average it.

I can see that you're wanting to work out the actual temperature from the ADC value.

Correct me if my algebra is wrong, but I thought voltage = sensorVal * 5/1024, based on the fullscale ADC is 1024 which represents 5 volts (default value)

Good example and explanantion is here.

https://learn.adafruit.com/tmp36-temperature-sensor/using-a-temp-sensor

There is another very useful command called Map, that allows translation from one set of values into a range.

Personally I use the DS18B20's for temperature measurement ...

I'd add a couple of the waterproof versions on your next buying trip.

Mark