user25931: My SD shield works nicely on 5v supply, but does not detect SD card on 3.3v. Could someone explain the possible reason behind this? Could you also provide a solution for this?
I've worked with it on Arduino Uno. Now I want to use SD card directly with ESP-12E to read its contents using SPI by doing something like this. Since ESP8266 operates olny on 3.3v, I need SD card to work on this voltage.
I've used two separate SD card shields without any luck! Photos of the two shields and micro-SD card are attached.





user-1: I could not find any info on the full size SD card adaptor, but the microSD adaptor has a 3.3V (LM1117 or equivalent) regulator on it. It, therefore, needs a minimum of 4.5V to operate.
To run the adaptor from 3.3V, you would have to remove the regulator and solder in a piece of wire in its place.

25931: <p>My SD shield works nicely on 5v supply, but does not detect SD card on 3.3v. Could someone explain the possible reason behind this? Could you also provide a solution for this?</p>

<p>I've worked with it on Arduino Uno. Now I want to use SD card directly with ESP-12E to read its contents using SPI <a href="https://www.reddit.com/r/esp8266/comments/48ib9g/connecting_a_sd_card_to_my_esp8266/" rel="nofollow noreferrer">by doing something like this</a>. Since ESP8266 operates olny on 3.3v, I need SD card to work on this voltage.</p>

<p>I've used two separate SD card shields without any luck! Photos of the two shields and micro-SD card are attached.</p>

<p><a href="https://i.stack.imgur.com/buF9C.jpg" rel="nofollow noreferrer"><img src="https://i.stack.imgur.com/buF9C.jpg" alt="SDHC card shield-front"></a></p>

<p><a href="https://i.stack.imgur.com/cRirB.jpg" rel="nofollow noreferrer"><img src="https://i.stack.imgur.com/cRirB.jpg" alt="microSD card shield-front"></a></p>

<p><a href="https://i.stack.imgur.com/ila5I.jpg" rel="nofollow noreferrer"><img src="https://i.stack.imgur.com/ila5I.jpg" alt="microSD card shield-back"></a></p>

<p><a href="https://i.stack.imgur.com/kPdiq.jpg" rel="nofollow noreferrer"><img src="https://i.stack.imgur.com/kPdiq.jpg" alt="microSD card and adapter"></a></p>
 -1: <p>I could not find any info on the full size SD card adaptor, but the microSD adaptor has a 3.3V (<a href="http://www.ti.com/lit/ds/symlink/lm1117.pdf" rel="nofollow">LM1117</a> or equivalent) regulator on it. It, therefore, needs a minimum of 4.5V to operate.</p>

<p>To run the adaptor from 3.3V, you would have to remove the regulator and solder in a piece of wire in its place.</p>
