Making thermostatic controller with RPi Zero W, thermocouple

[SQRT_Neg_1]

Hi all,
I am in the process of making an electric furnace controller using a RPi Zero WH, a Thermocouple Amplifier MAX31855 breakout board (#269), a Power Relay FeatherWing (#3191), and a 24x1 LCD display I had on hand. Since the thermocouple breakout and the LCD are supported through adafruit python libraries, seems that using the target platform to develop would be most direct, but I am running into problems using the Zero as a development platform.

I loaded RPi OS Desktop, then found I could not use both the keyboard and the mouse at the same time (works on an RPi 3 B+). I got a powered USB hub, solving that problem. I then found that turning on WiFi makes the display go black, then switch back on, several times per minute, making it impossible to use. Even with WiFi off, the display will blank out periodically, but only once every several minutes. I assume this is a power issue unique to the Zero, since the same setup, including the 2.5A power supply, works with the 3B+. The HDMI to VGA adapter I am using does get a teeney bit warm, but I don't want to buy a monitor with an HDMI port just to see if that fixes the problem.

This is pushing me to use my 3B+ as a development platform, then copy the python code to the Zero as the target platform. The question then becomes, how do I install the needed python libraries (CircuitPython, Blinka, MAX31855 module, LCD) on the Zero, given that it seems unable to access the internet? I would imagine these files, as installed on the RPi 3B+, can all be found and copied to a USB flash drive, then copied to the Zero, but I don't know where to find the files list, if such a thing exists. Even with that, I have up to this point been unable to mount a USB flash drive for writing, even when I specify the -w mount option on the command line.

Any assistance would be greatly appreciated.

Thank you,
Scott

[adafruit_support_mike]

I assume this is a power issue unique to the Zero, since the same setup, including the 2.5A power supply, works with the 3B+

That's probably correct. The RasPi Zero is an exercise in designing down to the lowest possible cost, and had to sacrifice things like robust power management to get there.

how do I install the needed python libraries (CircuitPython, Blinka, MAX31855 module, LCD) on the Zero, given that it seems unable to access the internet?

You can do all your development and testing on the B+, then move the SD card to the Zero-W when you're done. The OS works for both boards, and all the code you've written will work the same way on both.

[SQRT_Neg_1]

You can do all your development and testing on the B+, then move the SD card to the Zero-W when you're done. The OS works for both boards, and all the code you've written will work the same way on both.

Moving the SD card would include a lot of software I didn't need on the Zero, so I flashed an SD card with Raspian Lite for the Zero W and used a USB to serial converter for setup and ssh to log in from the B+ to download the required packages. I used sftp to copy my python scripts from the B+ to the Zero W.