“It Ain’t Half Hot Mum” or better said “baby it’s cold outside”

One thing we always need to watch is the temperature inside the engine room. Now we can be easy and just turn on a fan, and turn it of once we are done cruising. But why not make it automatic. We have arduino’s we have temperature probes….so lets do it, lets make it.
The other advantage of this method is, if the temperature rises even more we can automatically turn on a 2nd fan, to blow even more ‘colder’ air into the engine room.
This cruising year I’ll just watch how much the temperature handles and will decide then if I want the extra power blower option. But with the horrid warm temperatures like in the high high 30’s (C) we might need it.

Real simple to use are the DS18B20 waterproof temperature probes. They cost about $3-$5/ piece, are waterproof and are 3 wire. +5V GND and signal. The big advantage of these are that you can hook up a number of them on the same Arduino port ( -55C to +125C, with a 0.5C accuracy) . You can even get them with a BSP 1/2 Thread, like for your engine cooling circuit.

So I got a few of these on Ebay, connected them to the Arduino, used a 5K pull up resistor connected to the signal wire and +5V and first ran a program to get the Hex addresses, so I knew exactly which one was which one. (YES I copied and pasted it from the web !)
Voila the code…

Now that I knew the addresses, I could slap a program together which has an outside temp probe (AOT, actual outside temperature) and a engine room probe (AIT actual inside temperature).
All the speeches and articles I have soaked in about engine room cooling they keep talking about a DELTA of 25 F ( 13.8 C so 14C).
So the fan should come on if the AIT > AOT+14 . We do not want the fan to turn off at the same temperature point so, we turn the fan off if AIT < AOT+5, the last one is just a personal choice. To control the fan I added a relay board on it , connected the control wire to digital 7 and the relay works like a charm.

The relay is a 10 amp 250V relay. 1 channel relay board for Arduino, around $5- $6 on Ebay.

So the code is working, I will get a 4 line LCD screen so I can view the temperatures from the wheel and get a breadboard to solder the components on. More to come.

For those grumpy old man who remember the TV show “It Ain’t Half Hot Mum” it was a fun one!

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