Just in case someone is interested: here are some pictures of the internals of this ESP8266 based controller:
I got it quite cheap from Ali Express, and was curious about the internals.
Can’t complain so far; working as expected.
Looks like they redesigned it with a normal level shifter and a 33 ohm resistor.
Is the level shifter just the fet transistor? Or are they doing something else?
Level shifter is the 5 pin SOT with the 33 ohm resistor.
Do you know what kind of level shifter it is/or a good level shifter to use? I only saw the 164th 74ahc family or sot fet.
AHC is actually not recommended, although it can be used if combined with other circuitry to adjust input level sensitivity. The guide here recommends the HCT, AHCT or some LVC logic since they are simple and effective, but there are many others that can be used as well. I don’t know what that chip is, the label is not visible.
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Can you please link me the guide? I spent about an hour searching and reading various posts here. It’s tricky because slight change in letter makes a huge difference.
“the 74(A)HCT is the best to use”. Is the closest I found.
Here are some more detailed pictures:
Unfortunately I couldn’t find out what that “C34R” exactly is.
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74LVC level shifter:
Really? The “SN74LVC2G34 Dual Buffer Gate” is specified to have a 6-pin package for all variants.
make that a LVC1G and you got your single channel. if it really is a LVC type that zener diode better output 4.5V.
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Yah, the “34R” marking code points to the LVC device.
That’s a poor choice when powered via 5V (4.5V gets you barely in spec for voltage levels)
Bunch of other better choices - 74AHCT1G17GV (for eg.) would get you the same form factor and fully in spec.