I've spent the better part of a day researching how to send emails with ESP8266 and the Arduino. I've made progress but I'm missing some very basic point. To recognize the ESP8266Wifi.h I need to set the board to "Generic ESP8266" or something similar. The problem is I'm using the ESP8266 ESP-01S WiFi Serial Transceiver Module along with and Arduino Mega. So I'm doing a bunch of other stuff besides sending the email so wouldn't I need to set the board to Arduino Mega and the library should know to use the TX/RX pins to communicate to the breakout board?
I think I'm missing something rather fundamental. I've seen people connecting Arduino to the breakout but they just use the Serial monitor. Any guidance on where I should look next would be greatly appreciated.
Using an ESP and a Mega 2560 together sounds like asking for problems.
While you can do an awful lot with only the 4 I/O of the ESP-01, using an ESP with more pins brought out such as WeMOS D1 Mini should remove any need for the Mega.
have a look at ESP mail client
the ESP8266 is a 3.3V device and the mega 5V - connecting them would require level shifters - as @Paul_B states asking for problems
give us a outline requirements specification?
Depending on what you do exactly with the esp8266 you'll have to program it separately. You basically have two "Arduinos": the Mega and the ESP8266. They're both microcontroller boards; the Mega has many pins but no wireless, the ESP has few pins but it has wireless capability buult into it. So the ESP is not just a wifi module; it's a self contained microcontroller capable of pretty much the same (or more) as the Mega. So consider if you really need the Mega as you're complicating matters for yourself as @Paul_B says.
So that explanation is super helpful and basically what I'd come around to understand. Having said that, the ESP8266 ESP-01S WiFi Serial Transceiver Module I have only has 2 GPIO pins and I have seen tutorials showing it connected to an Arduino.
My project is a Well Pump control panel. I have buttons, an LCD display, several power relays, a real-time clock as well as an SD card reader. I have a Mega in the middle of it all and it works swimmingly. I just wanted to add the ability to send myself an email in the case of an alert. From the quick research I did (perhaps too quick) I thought this little module could be added. The tutorials show connecting the TX/RX pins and the 3.3v to the Mega board but they stop at any real functionality.
So do you know of a way to get my current control box to send an email? I guess I could look at a different format for an ESP8266 board to put in the middle but I wish there was a simpler solution. And I'm still scratching my head about the value of connecting this module to Mega if I cannot use the wifi libraries.
Understood but the Mega board has 3.3v pins, correct? This is how I've seen them connected. I have a project that includes several power replays, a display, buttons, clock and SD card. I just wanted to add something to send emails. It's clearly not as simple as I thought it might be.
I'm glad to have new information but I would think there'd be an option to add a WIFI module to the UNO/Mega to enable sending emails.
Thank you and I appreciate the response. I have an existing project in working order that includes several power replays, a display, buttons, clock and SD card. I just wanted to add something to send emails. So with the information I have now I see I can put a different board in the middle but I was hoping for something that could be attached to the Arduino UNO/Mega that would allow me to send emails. I thought the little module I bought would do it. Do you know of any other options?
you could connect a ESP8266 up to the mega via serial to send emails - not sure about serial on the ESP-01 though. Just be careful to use a level converter.
You could consider Arduino-MEGA-2560-With-WiFi-Built-in-ESP8266 - never used this device - the programming required for the builtin ESP8266 may upset the timing of the reset of your system.
I'm trying to learn so I'm not arguing but to be clear there are 2 GPIO pins and then TX/RX which could be used at GPIO, correct? So 4 possible pins but only 2 that are labeled GPIO (at least on the ESP-01 I have in front of me.)
The Mega has a 3.3volt/150mA power supply output that can be used to power external sensors.
Again, I'm smarter today than I was yesterday but still have a lot to learn. Thanks for the replies and I will keep at it.
looking back I see at some point I have connected an ESP-01 to a Mega - some notes on connection Connection to ESP_01 and level shifter from Arduino Mega GND and +5volts ESP_01 Tx to TX1 pin 19 via level shifter ESP_01 Rx to RX1 pin 18 via level shifter
clearly you have to program the ESP-01 - I used an ESP01 progeamer adapter
I have loaded the ESP-Mail-Client onto a ESP-01 and managed to read an email - not attempted to send emails
to repeat the Mega uses 5V logic and the ESP-01 3.3V logic - you can send signals from the ESP to the mega but any signals (e..g. serial Tx) from the mega to the ESP must go thru a level converter
I adapted the example from arduino-send-email which sent an email from a EthernetShield V2 to run on an ESP-01
when run it reads a text string from the Serial Monitor, creates a HTTP GET containing the text and transmits it to ifttt which forwards it to my email address, e.g.
Connecting to xxxxxxxx
.............
WiFi connected
IP address:
192.168.1.212
Enter a string of text ?
hello from ESP-01
Connected to server
GET /trigger/send-email/with/key/xxxxxxxxxxxxxx?value1=hello%20from%20ESP-01 HTTP/1.1
Host: maker.ifttt.com
Connection: close
HTTP/1.1 200 OK
Content-Type: text/html; charset=utf-8
Content-Length: 50
Connection: close
Date: Fri, 08 Apr 2022 08:10:48 GMT
X-Powered-By: Sad Unicorns
X-Robots-Tag: none
X-Top-SecreTTT: VG9vIGVhc3k/IElmIHlvdSBjYW4gcmVhZCB0aGlzLCBFbWFpbCB1cyBhdCBqb2JzK3NlY3JldEBpZnR0dC5jb20uIFdlIHdhbnQgTWFrZXJzLg==
ETag: W/"32-jD2lq/0l+3wF/IbKDa8EYJ8aOQ0"
X-Cache: Miss from cloudfront
Via: 1.1 5dcf6621f285f97fa4781de4d191d288.cloudfront.net (CloudFront)
X-Amz-Cf-Pop: LHR62-C4
X-Amz-Cf-Id: 5uBSA-fCh6mAgeKiEB7cBLow8fe9VzFtTeeElMeyMEMYLrHqZjy60A==
Congratulations! You've fired the send-email event
disconnected
Enter a string of text ?
I think I finally got it. I was all hung up on using the WifiClient and similar classes in the ESP8266 libraries. Then I realized how to send emails (or other serial communications) leveraging the SoftwareSerial library and I can how it can all come together. Going forward I'll look at using the ESP as the main chip.
if you already have a mega controlling your Well pump system, e.g. LCD, relays, etc you may find it a large task porting it to an ESP8266 - in particular some of the devices may require level converts to interface them to the ESP 3.3V logic.
it may be quicker to attach via serial an external ESP8266 device to send emails
porting maybe straightforward - e.g. change a few pin assignments in the code, change IDE target board to the ESP, compile, link and upload. Then add code to send emails.
The external devices (LCD, relays, etc) may work with 3.3V logic without problems, e.g. get another set of external devices (with 3.3V logic) and build new system which can be tested before attempting to replace the existing system.
Need to select an ESP board with sufficient flash, RAM, IO etc to support the application - if it to support a well pump system it may need to be of industrial quality???
The OP actually referred to a Mega 2560. Compared to an ESP, the only thing of any use that has, is a number of I/O ports and some analog inputs but port expanders and external ADCs can provide these with ease.
always tried to avoid port expanaders etc as they can complicate code and PCB layout
in cases where it looked like running out of IO lines etc moved too larger devices in the family
