PCB 2nd iteration works

A project log for Ventbot: warm side cool, cool side warm

A DIY register booster project to even out the temps around my home.

wjcarpenterWJCarpenter 12/30/2022 at 23:080 Comments

I received the shipment of revised PCBs from PCBWay a few days ago. I immediately populated one completely and tested it. I wanted to have one copy of the board that populated everything, including things that I don't plan to actually use myself. I'm pretty pleased with the little tweaks in the revised layout. And, it works! Here's a picture of it resting on a 3D-printed enclosure base. (I'm still fine-tuning the enclosure.)

I noticed one blunder that was also present in the first revision. The JST-SH and JST-PH connectors use the same order for the wires for I2C. I didn't notice that JST-PH connector was flipped over from what I was assuming. This is completely my mistake. Once I noticed it, the Adafruit article was clear enough. I just wasn't paying attention. Consequently, this PCB is not directly compatible with Adafruit STEMMA devices. For myself, that's not a huge deal since I am wiring up generic BMP280 breakout boards and soldering the wires from the JST-PH cable directly to the boards. I just had to ignore the wire colors (which were not applicable anyhow) and pay attention to the signal order from the board. In the generic JST-PH cables that I have, pin 1 is red, pin 2 is black, pin 3 is yellow, and pin 4 is white.

If I ever revise this design, it will be easy to correct this. If you use a "vertical insertion" JST-PH connector, you could just turn it around (notch facing the edge of the PCB), and then it would be directly compatible with STEMMA devices and probably also Grove devices. You could turn around a "horizontal insertion" JST-PH connector, too, but there isn't really enough space to insert the cable connector into it with that orientation.