Modifying Tuya Mini for No-Neutral Installation: Experiences with Diode Polarity Reversal?

>>20894879
Unfortunately the mini relay was too big to fit between my wall and switch so I haven’t been able to use the new version.

But I have moved the fusible resistor near the capacitor as on the new version and that reduced a lot the amount of power that it consumes so it will not burn by normal use.

Ps: some aliexpress modules like the aubess mini 16a have a little free space inside and some gpio ports unused, therefore it’s possible to fit the optocoupler part of the original design inside the module case (with the capacitor, diodes and resistors, but they must be soldered one to each other without a pcb so they fit in the least space possible). That allows very compact designs, just the diode on the switch, and just the module on the lamp (and the 400v capacitor with its diode and resistor if required by the lamp).

>>20824558
Getting back to this because sonoff basic r4 magic switch mode doesn’t work with all switch (specifically himmel)

So with the new modification I just need to replace the fusible resistors and the bigger diodes?

Hi




What current will flow through the diode in the optocoupler?
Won't it be too small?

Can anyone provide calculations?

>>21403807

This is the circuit that was tested and worked:

https://www.elektroda.com/rtvforum/topic3971605.html

In testing I used the components I had on hand at the time. The actual measured values ​​are:

- R1 and R2 are 45.9K and 46.9K
- The voltage measured on the pins of capacitor C1 is 1.1 Vdc
- The current consumed is 1.14 mA
- The alternating voltage of the mains supply: 236 Vac
- Peak network voltage: 332 Vac

The formula to apply is Ohm's law: V = I * R (V being the average DC voltage)
Vdc = Vp/3.14 (pi)
Therefore: I = (332/3.14) / (45.9 + 46.9) = 105.73 / 92.8 = 1.14 mA

https://www.youtube.com/watch?v=sekdEc5wU6k&a...b_ph_WdlLDny2cGloFSxyRgO8B733jeo&index=81

If we take a look at the optocoupler datasheet, that current of 1.14 mA seems very low compared to the 5 mA or 20 mA that it recommends, but the truth is that it works. To ensure those 5 mA, the resistances would have to be reduced to (18.5K / 2 = 9.3K).

Greetings