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SD Card Reader as a Voltage regulator?

PostPosted: Wed Apr 22, 2015 12:39 pm
by Lemon
Hello,

I couldn't find a better section for my question, sorry if it's in the wrong place.

I've recently joined the ESP8266 community after I saw how amazing this module is. The problem is that I don't have a voltage regulator and I really want to make the module work as soon as possible.

I do have a LC Studio SD Card Reader which has a built-in voltage regulator. You can see the photo of the module below. It's a fairly popular device. Can I use that module to supply 3.3V to the ESP8266 by connecting the reader to 5V pin of arduino and 3.3v pin of reader to esp8266's vcc pin?

Thank you!


LC Studio SD Card Reader:
Image

Re: SD Card Reader as a Voltage regulator?

PostPosted: Wed Apr 22, 2015 1:03 pm
by deadbok
Hi!

Yes you can. The voltage regulator (the four legged device under C3) is an AMS1117 http://www.advanced-monolithic.com/pdf/ds1117.pdf, and should be able to deliver 3.3V at 1A, which should be fine.

If you have some parts lying around, you can also make a regulator from a LED, a diode, a resistor, and a transistor:

Image

This is what I am currently using.



Hope this helps.
/Martin

Re: SD Card Reader as a Voltage regulator?

PostPosted: Wed Apr 22, 2015 1:10 pm
by Lemon
Thanks for the quick answer!

I'll switch to your design as fast as I can, I only needed a placeholder for now.

Re: SD Card Reader as a Voltage regulator?

PostPosted: Wed Apr 22, 2015 1:30 pm
by deadbok
I would not recommend my design as more than temporary. This is something that I threw together, wit the parts I had at hand. The output voltage is more like 3.6V, but can be lowered by removing the diode, or maybe replacing it by a Schottky type. Anyway you need to measure it before using the thing, it depends on the data of the LED (needs a voltage drop in the ballpark of 2.7V). Add a 100uf capacitor at the 3.3V output for good measure.

Using a 1117 should be better in every way, since it is more advanced and stable, than my hack. :D

Happy hacking.
/Martin