Ok so this is more of a general hardware design issue but it is for the custom ESPHome controller I’m trying to build to automate my Vornado Transom fans to work with HA to ventilate my apartment when it is cooler outside instead of using AC… I actually got ESPHome working with my prototype controller to do the speed/direction control and show up in HA (which is huge for me since my brain does not speak code and it took me WAY longer than it probably should have to get it working)… I started with that because I’m a hardware guy and I figured making the custom PCB would be cake if I could get the ESP to do what I needed it to do…Well, I went looking for parts to build the power supply and that’s where I’m hitting the real snag… My idea is to put the controller in the little cavity by the motor because there are mounting points that I can use.. But I can’t for the life of me find an off-the-shelf flyback transformer small enough to fit. The damper mechanism uses a 12V 28BJY unipolar stepper motor.. So I figured a 12V SMPS with a 3.3V buck for the ESP would be easy enough to put together.. That’s how the power supply on the stock board works.. But the smallest flyback I can find for the TNY268 is 24mm - which is way too big to make a board small enough to fit where I need to put it.
I mean, I fully understand the risks of non-isolated power supplies but where it will be there is nothing that can cause a shock hazard. The fan casing is all plastic and once it is installed it will be sealed inside. The problem is that when I went asking for help with the coding in the FB group (I’ve since been thrown in FB jail for a month lol) several people expressed interest in buying controllers from me and I can’t trust that THEY would understand the risks. Does anybody have any other ideas? I want to do this the right way but the ~9mm flyback they used in the stock controller seems to have been custom made for the application. I found a monolithic 12V 400mA PCB mount SMPS that’s 22mm square that could work but they’re $30 apiece. I’m not looking to build a $50 controller.
As a side note this is the “Alexa enabled” version of the fan. It has a ESP32 in it already (sold by amazon as the “Alexa Connection Kit”) that talks to the onboard MCU over UART. It was suggested that I try to “take over” that ESP32 and flash it with ESPhome but again that is not something I am any good at. That would also exclude anyone with the non-Alexa version from direct ESP control (one person told me he was relegated to automating with IR control which I specifically want to avoid due to the possibility of it going out of sync unnoticed). If you help me find a workable solution and you have these fans, I will build you a controller for free!
