"A bit cheeky..." 2

The SMD soldering went..er...let's say it just went. I don't usually enjoy it, but the results didn't look too shabby. After a quick "smoke test" with the meter, I checked for continuity where expected, and not where it was not. All good.

Then - just to show how paranoid (read "safety conscious") I am with mains electricity - I built this little rig so I don't have to go anywhere near it while its under test and can be done fully hands-off. So much so, that the mains plug is into one of my WiFi truc devices and switch remotely from the bench! "The management eats here".

The PCB is a 1" square type that I came across on ebay some while ago - they are absolutely indispensable for knocking together little bits like this: buy them here. The came as 24pcs for eu6.62 or a measly 28c each - my kind of component. I always keep plenty in stock.

Anyway, once the power went on:

I would have hoped for a little closer to 3.3v but a) its all cheap parts b) its a cheap meter c) I'm sure it will be fine d) I'm over the moon it worked at all!

Find out if I'm right when I start the first "production" build of my ESP-01S powered wall switches which this PSU is for!

A bit cheeky...

I recently bought some of these AC-DC converters from ITEAD to run my truc devices from the mains. Mainly they are Wemos D1s but I also decided to build smart wall switches using ESP-01S as they are very small - but they run on 3.3v.

Click here to buy them yourself

"No problem...", I thought - "...looks like they do 3.3v too - bonus!". If you follow the link above to buy one, you'll see that ITEAD's latest photo has no 3.3v pin any more and on closer inspection of my own units, I can see why:

Seems that they are economising the few extra cents per unit of a 3.3v LDO...To be fair to them, the unit is clearly advertised as 5v and that's what I bought it for, but I couldn't help thinking "a ha'porth of tar..."

I also couldn't help thinking that if I could buy a few cheap LDOs in SOT-89 format with the right pinout, then I could right this "wrong". Don't misunderstand me, I'm very happy with ITEAD products and I have bought a lot of them - I trust them and I highly recommend this one, but...you know what I mean?

Anyways, it took a little research to find the right part, and as usual (I get the majority of my components from ebay.com) I found a seller doing five AP1117Y33L (here) They are incorrectly tagged as "Diodes" - but that's half the fun of ebay isn't it? Either way, they are what I needed.

There's a whacking great cap on the input side (470uF) but - as you can see - none on the output side. The datasheet for the AP1117Y33L states it needs a 22uF cap on the output for stability. So as long as I hook one up there on the final board, I should be "quids in".

Now all I have to do is a) bemoan my failing eyesight and b) get the fine tip on my soldering iron and "bite the bullet". If you aren't a big fan of soldering SMD parts ("fiddly" ain't the word), look away now...

I shall report back in due course.