SD and WIFI Shield

Using Arduino Networking, Protocols, and Devices
1

I'm new to Arduino and have gone down a few blind alleys. Although you often learn from this, it can be quite frustrating.

I want to try using a WIFI shield but i also want to habe an SD shield.

Using the standars libraries, both WIFI ans SD use the same pins. Does this mean that you can't use both on the same setup, or just not use both simultaniously.

I would assume that you will nee to open 1, read, close 1, open 2, write, close 2.

Or am i barking up the wrong tree?

2

for WiFi consider a ESP32 which has onboard WiFi, Bluetooth classic and BLE
for connecting an SD reader try a web search for esp32 sd you will get plenty of links

3

Which Arduino board do you have ?

5

depending on your shield, it is very likely that WIFI uses Pin 10 as Chip Select and SD uses Pin 4 as Chip Select.
MOSI, MISO, SCK are shared, as SPI is a BUS - only the Chip Select pin will differ.

and as already mentioned by @horace : ... if you plan to use WIFI ... get a ESP32 Makerboard as replacement for the Arduino.

6

Im using an elegoo R3 (2560) which I got myself at Christmas as part of " The Ultimate Starter Kit ".

It didn't come with WIFI, Bluetooth or SD modules and so i got a selection from aliexpress.

The WIFI shield that I have is ESP8266 ESP07, and the SD shield is a TF card module. I've got my head around using the SD card but haven't tried the WIFI yet.

I have read Simon Monks "getting started" book and I am now reading his "next steps" book. They are really good books.

In the future I will probably try an ESP32, but at the moment I am just trying to get my head around the basics using my Elegoo.

Thanks for your comment noiasca, that's the type of thing I was hoping for. I don't want to go banging my head against a wall trying something that isn't supported.

7

this ESP8266-07-Programmer-With-Arduino-Nano tutorial may help
be careful - the ESP07 uses 3.3V logic the Uno is 5V logic - you will require a potential divider on the UNO Tx to ESP-07 Rx line otherwise you may damage the ESP-07
using WiFi would be a lot simpler using an ESP32

8

Thanks for your help.

After a bit more research, it appears that there is a bit of work to do to reprogram the ESP8266 chip. I can understand why the a ESP32 Arduino if preferable.

Have i understood correctly, it appears that the ESP8266 is a more powerful microcontroller than the AtMega 2560.

9

the ESP8266 and ESP32 are faster than the Mega, have more flash and SRAM memory
ESP8266 has builtin WiFi - only has one ADC
the ESP32 has Builtin WiFi, Bluetooth Classic and BLE

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