Mega plus board with ESP 32

@dastardlydoug I think you forgot to include a picture.

An UNO and ESP32 will fit inside a box half that size, so I don't see a problem. I have a board that has both those devices on one board (8266 for the WiFi vs ESP32). The combo board is 2.5" x 2"

I'm really curious... What kind of project do you have in mind that would utilize both?  There may be a good use case, but I don't think I've ever heard of one.  Usually the intercommunications between the two will handicap both of them (but mostly the Mega) from the actual duties of the project.  Then there is writing all that communications code.  You'll spend tons of hours and hundreds of lines of code just telling the other one something project specific. 

All the CPU horsepower is on the ESP32  (as much as 30X the Mega).  And although the Mega has tons of Analog and digital pins, there are plenty of dumb chips that that can add those capabilities to the ESP32 and do everything the Mega can. 

If you are just interested in a self-learning experience, then the most common is to set up Serial communications between the two.  A Google search will probably find many fine tutorials.  "Serial communications ESP32 to Arduino Mega" - Something like:  https://www.programmingboss.com/2021/04/esp32-arduino-serial-communication-with-code.html

@inq @dastardlydoug I think he wants wifi, the combo uno + 8266 is my recommendation.

The website https://create.arduino.cc/projecthub popularizes the combining of an Arduino based board to an ESP based board for just that purpose.  They actively encourage special treatment of any projects that use an Arduino product.  That's the only way they make money.  I applaud their marketing, but it makes no technical sense to me.  Thus... people go out of their way to add an Arduino.  I've even consider adding an Uno to my projects there and showing it used as a door-stop in a picture's background.  I have at least two sealed Mega's and a dozen other Uno, mini, micro, nano...  waiting for some project to justify me reaching for them off the top closet shelf and blow the dust off them.  

With my current understanding, I see it like putting a trailer hitch on a Ferrari and towing a Conestoga wagon.  

@inq @dastardlydoug Given his project, he can easily do it with an esp32 and probably an esp8266 if there are enough pins. Not sure why he needs an UNO.

I just want to make my plants get watered from a holding tank when they get to a certain % of moisture...

Have exhaust fans turn on depending on temp/humidity...

And then be able to access the readings from the dashboard on the IoT cloud.

I can cross out the fan part, as I bought a plug & play sensor with two programmable outlets. But still wouldn't be able to get any info away from home.

@dastardlydoug You can do all that with an esp8266 or esp32 but not an uno, it does not have cloud abilities. Same IDE to program, same C language (C++ if you need to create libraries (NOT likely) or classes etc (NOT likely))

I think it will depend on @dastardlydoug 8 channel relay selection. Some need 8 pins to control. An ESP32 has plenty of pins to handle that. Even an ESP8266 NodeMCU could handle that with pins to spare for sensors. They also make 8/16 channel relays with an I2C interface... and thus only two pins are necessary. Even an ESP8266 WeMos can handle that with pins to spare.

I recall from his intro thread, he was concerned about security. I'm guessing SSL. I guess where I live, I've never been too worried about someone stealing my temperature/humidity data... even if they could Sniff and decode my data streams. I understand SSL is a little easier on an ESP32.

@inq If by security he is talking WiFi, then the board is irrelevant I think, it's just a matter of software configuration, https, ssl etc. Not an expert, but I know security is a BS argument. The only security with signals is to not emanate any, use a cable and guard dogs.

Posted by: @zander

The only security with signals is to not emanate any, use a cable and guard dogs.

😉

Posted by: @inq

I think it will depend on @dastardlydoug 8 channel relay selection. Some need 8 pins to control. An ESP32 has plenty of pins to handle that. Even an ESP8266 NodeMCU could handle that with pins to spare for sensors. They also make 8/16 channel relays with an I2C interface... and thus only two pins are necessary. Even an ESP8266 WeMos can handle that with pins to spare.

I recall from his intro thread, he was concerned about security. I'm guessing SSL. I guess where I live, I've never been too worried about someone stealing my temperature/humidity data... even if they could Sniff and decode my data streams. I understand SSL is a little easier on an ESP32.

I guess the whole reason I felt I needed the Arduino was just for the inputs/outputs.

From what I can see, the ESP32 has too few of anything, and just want it to make data available in the cloud.

@zander 

I have a friend that teaches internet security in college.

He said that if I just have a second router, and minimalize connections, that nothing will penetrate my home network. ifttt stuff.

THIS... Is not where I want to go 🤣 

Posted by: @dastardlydoug

I just want to make my plants get watered from a holding tank when they get to a certain % of moisture...

I don't have much experience using the IoT cloud services.  The few tutorials I've worked through seem like they make it pretty simple to implement.  I prefer to keep the ESP servers inside my LAN and access the dashboards on any other devices on my LAN.  I don't really have a need to monitor/control them from afar.

What type soil moisture sensors are you using?  You mentioned you don't like one type.

https://www.amazon.com/UMLIFE-Capacitive-Moisture-4Channel-Detection/dp/B093V62VXD