POE Design - the longest part

A project log for Blind Motor

A motor to roll up my blinds, controlled by Home Assistant

nagupnagup 04/22/2021 at 20:180 Comments

Still working on the POE board. I think I'll need a board to do the conversion of POE to 12v 30W and a separate board where the esp32, stepper driver, and other electronics will be attached. I am following a reference design from TI but I am still looking at other designs which are smaller and have a low BOM cost to hopefully only have one board. This reference design is very expensive (estimated about £40 per board) so I will most likely stick to using the schematic of this LILYGO board as it's definitely cheaper, and simpler although that schematic is for a 5v output so I'll need to figure out how to get 12v if it's possible, I am way out of my comfort zone and well past my knowledge barrier that's why it's taking so long. If I'm not confident with the design I may make an evaluation-style board just for testing and it will allow me to make some changes to the connections and will have footprints for different components, I'll also be able to see if any components need more cooling although I will be following advice for the layout in the datasheets. 

After this POE design is done I will move onto creating an enclosure for the PCB which is attached to the rest of the mechanism. After that, I'll do some finishing up of the esphome and home assistant stuff. 

I have been using the mechanism and electronics since the last update and from using it I have discovered that the esp32 doesn't boot reliably, sometimes it takes ages for the device to show up as available in HomeAssistant and sometimes it appears within a few seconds, and then sometimes it will go offline while the blinds are going up or down and I have to quickly scramble to disconnect the battery. The wizards in the Esphome discord should be able to help me out with that.