Arduino, Thermocouples, MAX31855K (vs MAX6675) and SPI – The Fine Points

It can’t be that hard to get a MAX31855K up and running …
↓↓↓ Complete description, time index and links below ↓↓↓

Or so you might think. But if you have one of those simpler Chinese modules you’re facing a challenge right out of the gate: it won’t work without modification. And if you have to 5V MCU, you’ll need some level shifting down to 3.3V.

There’s a nice MAX31855 library available for Arduino, but you can also bit bang the SPI bus directly. Multiple slaves on the SPI bus are a must of course. But do you really need a MAX31855K or will a MAX6675 just do fine.

00:00 Intro – Arduino, MAX31855K and past MAX6675 videos
01:04 MAX31855K vs MAX6675 – datasheets, differences, similarities
07:53 Input filtering – strongly recommended, in fact required
09:33 5V operation – connecting the 3.3V MAX31855 to a 5V MCU
12:49 MAX31855 library – by Rob Tillaart, easy and lean
17:57 Bit banging – code for the MAX31855K with just the SPI library
29:08 Multiple MAX31855Ks – on the same SPI bus
31:47 Mixing 5V and 3.3V – devices on a SPI bus is complicated
32:58 5V compliant modules – they are not, at least not fully
35:06 Shorting things – and destroying MAX31855s
36:22 Wrap-up – verdict, link to code and bye

Tutorials:    • Tutorials  
Mini Mailbag: Breakout PCBs for HB100 Doppler Radar and MAX31855K Module    • Видео  
Arduino, Thermocouples, MAX6675 and SPI – The Fine Points    • Arduino, Thermocouples, MAX6675 and S...  
Faulty Chinese MAX31855K Modules: Fake Chips? No! Just a Capacitor Missing!    • Faulty Chinese MAX31855K Modules: Fak...  
Galvanic Isolation of SPI Devices (e.g. Arduino, MAX6675 and SI8631)    • Galvanic Isolation of SPI Devices (e....  
My Arduino code https://drive.google.com/drive/folder...
GitHub – RobTillaart / MAX31855_RT https://github.com/RobTillaart/MAX318...
Adafruit Thermocouple Amplifier MAX31855 breakout board (MAX6675 upgrade) https://www.adafruit.com/product/269

#thermocouple #MAX31855 #Arduino #SPI #tutorials #tutorial #how-to #robertssmorgasbord