ReflowESP bugs found - Githubissues

LuigiPapparotti commented 2 weeks ago

To detect correct communication with the MAX31855, a pull-up resistor must be added between the MISO pin and VCC. Without a pull-up, random noise may appear that might look like real data.

Read here: https://github.com/RobTillaart/MAX31855_RT?tab=readme-ov-file#pull-up-resistor
Capacitors C1 and C5 are connected in parallel. One of the two is unnecessary.

Weissnix4711 commented 2 weeks ago

Thanks. I'll probably never have a rev 2 of this board manufactured myself, but feel free to fork and fix this yourself.

Also, for what it's worth, I've never had any issues with using the internal pullup only.

LuigiPapparotti commented 2 weeks ago

That's really a shame.

I came across the problem after testing your circuit on a breadboard. If one or both MAX31855s fail, real temperature values are still displayed. After inserting the pull-up resistor, I get the correct message "129 No communication".

I have since made the following changes to the circuit:

Fix: pull-up resistor on the MISO signal line of the MAX31855
replaced the ESP32 with an ESP32-S3-WROOM-1-N16R8.
added a TF-SDCard socket.
added an input to the inputs so that you can use either a rotary encoder or 4 x tactile push buttons.
the resistors can be used as pull-up or pull-down via a solder jumper

Weissnix4711 / ReflowESP

ReflowESP bugs found #1