Project: DS18B120 Dallas temp sensor chip VS MAX31855K Thermocouple amp chip

[cobbler]

Feel free to tear this apart and tell me what I did wrong, I am interested in building a project to monitor the heatsink in high output Cree COB LED lights. These LEDs are extremely efficient (~70%) but get extremely hot and put out a tremendous amount of light. The Cree COBs being used for the test are model CXA3590. The CONs are being driven by very efficient Meanwell HLG-185H-C700A LED drivers.


So the plan is to have a LCD display showing the temperature of the high output COB LED. The DS18B120 Dallas temp sensor chip is thermal pasted directly to the LED ceramic collar. After this first simple test is done, then I will add the MAX31855K thermocouple amp chip with a thermocouple wire attached to the other side of the LED collar. Then we can see which one is more accurate and how they perform.


More detail to come but here is a video of the DS18BB120 Dallas chip being tested. It is very accurate!



So the temperatures mentioned in the Cree datasheet are important so the light runs efficiently. This test is pretty accurate, it is not measuring the aluminum heatsink temperature, it is monitoring the COB directly. The temperature is requested every ten seconds by the microcontroller and then logged to LCD and serial output.
This is just for a temporary test of everything- to help read temperatures. Obviously in a production environment you don't need any of this- or if you want to have it, mount everything more secure and permanent.


Parts:
Arduino UNO R3 
LCD Display model 1602
Breadboard Kit
Ethernet cable
3pin cpu fan connector


1x  5M ohm resistor
3x  220 ohm resistor  (or 1x 1K ohm resistor)
3x  DS18B120 Dallas temperator sensor chip
5x  Cree CXB3590 COB LED
1x Meanwell HLG-185H-C700A LED driver


Part Pictures: