Hardware Developement

ESP-PROG

I was looking into a JTAG-esque header for this project, and was reminded of the ESP-PROG board by Espressif. It is available from Mouser

I was unaware it worked for the ESP8266, but after ordering one, I have confirmed that it does. I then put a ESP-PROG header on my board. ESP-PROG setup

To flash from WSL Ubuntu, I used the command: idf.py flash -p /dev/ttyS9 -b 115200

Layout

Using KiCad, I’ve drawn up a board for my temp probe. I followed this tutorial for layout. I also had a bunch of help from some friends and a few people from the Embedded.fm Slack channel.

board layout in kicad

Top Render in KiCad: top render in KiCad

Bottom Render in KiCad: bottom render in KiCad

I found a useful collection of open source KiCad Libraries

I decided to go with a JST XHP-3 Connector for the DS18B20.

Manufacturing

JLPCP is what I used, which was recommended in the youtube video.

There are useful tools to generate BOM files for JLCB, such as this plugin

There is also another interesting BOM generator I did not have time to test.

I sent the design out, only to find out that the footprint for my LM3671 was wrong. I had used a SOT5x3 vs SOT23 Luckily, they caught my error, and I was able to cancel the order with populated components.

I did, however, keep my order of unpopulated PCBs. It was cheap enough, and it was a good silkscreen test. I ended up adding some pictures of my dog, because why not.

The silkscreen came out pretty good V1 Rev A board

Here is a grayscale render. I’ve been looking into a way to render more than stls.

I’ve sent out a fixed version of my files to JLPCB, and am awaiting populated boards.

Next Steps

Hopefully my fixed rev B of the board arrives, and I can load software on it. The production version of software is still in progress, so I plan to continue work on that.

Future Plans

I plan to cover the vinyl portion of the DS18B20 with food grade tubing