Resistor for Nano Arduino circuit

I'm trying to work out what resistor to get for the Nano Arduino circuit for this mini fridge build. From the photo it looks like a 5.6K 1%, but I have no idea what wattage? In the circuit diagram it is listed as 4.7K with no other details.

www.instructables.com/id/DIY-Portable-Mini-Refrigerator/


Any help would be great!




ggom2017 days ago

Any 4.7k 5 % or 10 % should do.The value is not very critical.

1 percent precision is not needed it is not analog signal line.

it is a one wire communication bus witch only needs a pull-up resistor

For more information:

https://datasheets.maximintegrated.com/en/ds/DS18B...

Regards.

And btw

+1 with Downunder35m:

Using a microcomputer, digital hight precision 12 bits sensor+power switches, for a fridge thermostat looks just a bit overkilling and costly too !

Anyway learning to use an Arduino is a great occupation.

And could lead you to many more projects.

Regards

gg

iceng18 days ago

Downunder is correct that is what I call a pull-up resistor and can be as small as an 1/8 watt resistor.. It's job is to make sure the Mini Arduino digital input D2 has a positive voltage such that the open collector thermal sensor circuit can pull down (change_voltage) at the desired temperature..

1/4W should do, it is just to get a clear signal from the sensor and no real power goes through there.
You can also use a simple and salvaged fridge temp sensor if you want to avoid all electronics.