I’m excited to reveal the hardware I’ve been working on to go along with the heat pump feature in the v1.5-dev image that I’ve been working on. Here’s what changed:
- Supports up to 5 relays, enabling 3-stage heating
- Socketed pi, so it can be upgraded/replaced in the future
- Power switch so you can reboot whether using the Pi Zero or Zero 2
- Ribbon cable to the LCD so pins don’t get misaligned and the case is easier to put on
- This is by far the #1 complaint I’ve heard
- All of this, and it’s still compatible with the same case
This is what it looks like when populated with 3 relays without and with the pi inserted.
Here’s a shot of the bare PCB, front and back.
Sponsor: The reason I was able to do this hardware development was because PCBWay sponsored the first prototype and one revision. The ordering process was straight forward and I had the boards in hand within a week of when I placed the order. It was a 3-4 times faster than I’m accustomed to when ordering from overseas! Prototyping is expensive, especially when the shipping costs as much as the product, and the taxes push those costs even higher, so I really appreciate them reaching out.
Disclaimer: The current boards I have work fine with 3 or 4 relays, but unfortunately, somehow the ground pin of the 5th relay didn’t get connected (design error, not manufacturing issue). It can be jumpered to get it to work, and I’ve fixed the KiCAD design file, but I haven’t gotten another batch of boards made to physically verify everything.
Release: I will be making the new boards available in the store later this week, either as part of a kit, or as a fully assembled unit. I’d like to get PCBs made of the final KiCAD file to do final testing before releasing the design files. I don’t want people to use an old or untested file and get an imperfect board. If people really want the KiCAD files before I test them, I am willing to make them available. I have been versioning each file and printing the version numbers on the back, so if someone does order an old version, we’ll at least be able to tell which design file they’ve used.