Hardware Selection for New Project

Hi all. First post and an Arduino newbie. However, I am very familiar with hardware and embedded firmware development – just not the Arduino ecosystem.

I have a first project in mind and know the capabilities I need: microcontroller, WiFi connectivity, LCD display, and user input push buttons. After some Googling, I came up with this hardware combination:

Arduino MEGA 2560
https://www.arduino.cc/en/Main/ArduinoBoardMega2560

Arduino WiFi Shield 101
https://www.arduino.cc/en/Main/ArduinoWiFiShield101

Adafruit LCD Shield

So, the basic question is, can I just stack these boards one atop the other (obviously with LCD display on top)? How do I know if there is any conflicting pin usage between the WiFi and LCD shields? Also, from the picture it looks like the WiFi shield doesn’t pass all the Arduino’s connector pins through from bottom to top. So, I might have to bring some pins up directly from the MEGA 2560 to the LCD (going “around” the WiFi shield)?

Since I’m not mass producing this project, low cost is not a prime consideration. More important is to get going with minimal superfluous futzing around. A little hardware modification (like extra wiring) is fine. But, I don’t want to be hunting the web for obscure firmware library hacks necessary to make this combination of hardware work.

Sorry this post is kind of long, but I hope it clearly defines what I need to know.

Thanks in advance for any help.

Greg

But, I don't want to be hunting the web for obscure firmware library hacks necessary to make this combination of hardware work.

@Greg:

No one likes to hunt for libraries and such but while you have told us about the hardware you selected, you did not mention anything except WiFi and LCD. So, are there sensors? Your selections must match the Mega2560 which takes a special shield to have access to the large number of I/O signals.

I believe that if you go back and look at the Adafruit display you selected you will see it is not a shield for the Mega2560 although it would work alone.

This shield will not fit easily on top of an Arduino Ethernet because of the Ethernet jack height. You can use a set of stacking headers to give the shield more 'lift' above the jack.

Try this Google search to see what is available however I suspect some of our members will chime in about displays they have used and recommend. Personally, shields are not my thing.

Ray

Hi Ray, thanks for the reply.

I didn’t mention the sensor because its interface is so trivial. It’s a load cell amplifier with integrated A/D converter.

Just a two wire interface. I figure there will be plenty of MEGA 2560 I/O pins to choose from even after interfacing the WiFi and LCD. Also, there is a library already available that handles the bit banging. So, I think I’m covered with the sensor.

I saw the quote about the Adafruit display. But, I’m using the WiFi, not Ethernet. So, there is no jack height problem since there is no jack. Also, it says it works with MEGA R3, is that different than MEGA 2560? I choose this shield because it only requires a two-wire I2C interface to control everything. Again, there’s already a library for it too.

So, all things considered, I think I’m good with total number of I/O pins. My main concern would be pin assignment conflicts. Also, should consider if the regulators on the MEGA 2560 can supply enough current to also power the WiFi and LCD.

Greg

Hi,
Basic question: why do you feel you need an Mega??

I/O pins?? Do you have some large other devices you didn't mention?

Code Space?

An UNO will cover most applications...

It looks like those two shields will stack OK. But if you need access to other I/O pins you will need to make the "stack" higher so you can get the wires out from UNDER the WiFi shield. Stacking connectors like :
THESE

Disclaimer: mentioned stuff from my own shop!

terryking228:
Basic question: why do you feel you need an Mega??

Two answers:

  1. The library for the WiFi takes up a lot of code space.

  2. For a $20 difference, why screw around? Get the bigger device in case I want to repurpose it for a more advanced application later.

gfvalvo:
Two answers:

  1. The library for the WiFi takes up a lot of code space.

  2. For a $20 difference, why screw around? Get the bigger device in case I want to repurpose it for a more advanced application later.

However, I am very familiar with hardware and embedded firmware development -- just not the Arduino ecosystem.

IMO, there is no reason not to purchase the Mega. Many newbies have a slim budget and the Mega2560 is a rather pricey 8-bit board. Since you are already knowledgeable with hardware and limitations, is there some reason you are not moving into 32-bit uC boards? You can look over a few of the projects that I have recently completed (12 months) using the $4 ESP8266 here. There are several U.S. eBayers that sell the ESP8266 at a bit of a premium but they are U.S. based and you get your package in a week instead of the slow-boat out of China.

Ray

Added:
I'm sure you noticed that the 'real' Arduino WiFi board is obsolete although you can get clones easily. One thing to note here is that the 2GHz "N" protocol is not supported but is on the ESP8266. The WiFi libraries are almost a clone in capability and calling parameters. Additionally, all of the "NodeMCU ESP8266-based boards have 4G of Flash space available, 3G of which can be formatted as a SPIFFS (file system) for webpage code. In this project, I am using the 3G of SPIFFS to store a javascript interpreter, graphics, and HTML5 code for the client-side.

The down-side to the ESP8266 is just one analog input, A0. The ESP32 port of Arduino (in the works) will support more analog inputs.

mrburnette:
I'm sure you noticed that the 'real' Arduino WiFi board is obsolete although you can get clones easily.

I noted that the original 'real' Arduino WiFi board is obsolete:

My intention was to use the WiFi 101 board which is not listed as retired:

Are you saying this is discontinued also?

gfvalvo:
<…>
My intention was to use the WiFi 101 board which is not listed as retired:
https://www.arduino.cc/en/Main/ArduinoWiFiShield101

Are you saying this is discontinued also?

Looks like the WiFi 101 is the current model … my bad by clicking on the 1st google results.

Ray