Home Assistant Wifi Phase Cut Dimmer

[@andrewreid5355]

Great work mate! Exactly the project I’ve been tinkering with - your approach using the DAC seems a lot better than my thought of using a digital potentiometer. Really keen to see how you evolve the design.

[@SparkyJames]

I did think about using a digipot, but the DAC worked out cheaper and posibly a little bit more accurate, and pretty simple to use. The one thing the digipot has in addition to i2c, some have a manual push button up and down to adjust the level, that might have been handy for local control at a wall switch. It's fun though trying out different stuff and seeing what works out best!!! Enjoy your tinkering!

[@MrDwienie]

Hi Jimmy , I did almost the same to connect to esphome but with an attiny84, I added the wire library in the attiny , so the attiny is do the dimming and also is doing the dimming levels through I2C. So I only need one IC to do the I2c and the dimming but like you I have issues with the lower levels in dimming. It start to flicker in the lower levels. I see you fixed that with the map function. I am wondering if you found some good dimming leds that doesn't have that flicker behavior because sometimes you want to create an ambiance that requires that kind of dimming.

[@MatiasJHZ]

Have you tried the 2 wire design? I've been puting a lot of thought into how do they get power from that design. The VDD pin (internal regulator output) supplies very little current (and therefore, little power). Ive been thinking about putting a switching power supply conected to the VS pin (17V if I'm not mistaken). I don't know if a LDO after that switching supply would be necessary or if it is just enough with sufficent capacitance. Do you think that would work? The 220Vac/5Vdc module really takes a lot of space and I would love to not depend on a neutral wire. Great project and great work! I'm looking forward to do the same.

[@NeilStansbury]

Did you try this? I'm considering using an MP2325 buck to take the 17v down to 3.3v to supply an RP2040. The 17v would also be plenty to drive a 0-10v dimming rail to control the FL5150

[@MatiasJHZ]

I did not. The main issue is that if you want to control it using a microcontroller and a DAC or digital dimming, you need to keep power consumption as low as possible. In the 2-wire configuration, a little voltage is drop from the mains (when the "switch" is off) to maintain the supply of the electronics, so you can't fully reach 0% or 100% dimming. This form of dimming I think is called back-to-back mosfet or IGBT but I am not quite sure how it works. I haven't found proper documentation explaining how back-to-back mosfets work in dimming applications. If you find anything that would be helpful. I am sure you can do that. I also plan to use a regulator or converter to have a supply for the microcontroller, but that's the price to pay, a minimum Ioff current through the load. And the larger your power consumption, the greater the Ioff current needed in the "off" state. This is an issue when your AC LED load draws little current. Usually there is a minimum load in these kind of circuits to properly work.@@NeilStansbury

[@raviteja8335]

Nice work Jimmy James. It's look like interesting and can you please post the circuit of the project.

[@SparkyJames]

Hi Ravi, thanks. I have updated it for you here easyeda.com/james_6977/fl5150-modified note that R9 is a 1w resistor. I was using a 1/4w and it was too small the, the datasheet does indicate that this resistor may pass up to 475mW at times, so I throught a 1w may be a good idea.

[@raviteja8335]

@@SparkyJames Thanks for the information. In the circuit, there is no isolation between AC and DC. Can we bring isolation between it?

[@MichaelRiksman]

@@raviteja8335 If you have an example, I'd like to see it. Jump on EasyEDA, clone Jimmy James project, and make the modifications.

[@clkunde]

Congratulation. Very good!!!! Which part number the IGBT is?

[@SparkyJames]

I've used 3 and they al work fine, I got them from LCSC IKA15N60T - FGPF15N60UNDF - STGF14NC60KD

[@PatrickFelstead]

Hi James. What are your thoughts on Shelly 2.5? I bought a couple to try out, and they get pretty hot. Given you're a sparky you probably have a better idea what is too hot for something that's meant to go in your wall space! If you're on the HA forums, I did a detailed post about it. See here community.home-assistant.io/t/shelly-2-5-getting-hot-to-touch-63-c-external-case-should-i-be-worried/175376 if you have time. Basically they get very warm when the output is off (about 47°C) and with one 8W LED downlight on each output, just below 60°C!!

[@SparkyJames]

I found the same with the Shelly 2.5 is get quite hot. When we do thermographic testing I regularly see relays etc that are 80 deg and as you commented drivers and transformer can get pretty warm too. That's all normal and most building wire we use in Australia is v90 which means it can get to 90deg safely. The main thing to consider is not placing electrical items that run hot near a combustible material and if possible they should be enclosed in a wall box that's sealed so fire can spread, it if did fail.

[@PatrickFelstead]

@@SparkyJames thanks good to know about your thermographic testing and v90 and that the higher temps seem fairly normal. I guess I still feel uncomfortable as most other home automation devices that I've used run cooler. So is gyprock (dry wall in USA) considered "combustible"? Probably can't put them in a fire proof metal wall box as that would block the wifi signal...