Arduino UNO with 16x2 LCD Shield and DHT22 sensor for Humidity and Temperature

Dear forum,

I am starting with an Arduino project and I have a very straightforward question.
I will need to measure the RH and T from a DTH22 sensor and to read the data in real-time on an LCD screen.

I was thinking to buy:

an Arduino UNO,
the LCD shield
the DHT22 sensor

and then use the I/O on the shield to connect the sensor. Is it right? I mean for what I understood I can still use all the pins for inputs and outputs because they will be on the LCD shield. If I am not wrong.
I got confused because lot of projects online or on youtube use the LCD on a separate board and connect the sensor to the inputs and outputs pins of the UNO.
What is wrong to stack the LCD shield on top of the UNO and use the pins that are actually THE SAME as the one of the original UNO??? This got me a bit of confusion...Sorry.

Also, I would like to log this data (perhaps on an SD card?) and use them in an Excel file for example.

May someone kindly tell me if I am having the correct approach to the project or give to me any sort of advice to make me reflect about it please?

Thanks a lot. Any help will be really appreciated.


You are correct, that the pins are straight though, but as is clear, you need to establish from the circuit diagram of the shield and / or is software , which pins are dedicated to the lcd function as they will not be usable for other functions (generally)

A lcd shield is great for early learning and avoids the very common wiring problems of a lcd.

As you devlop, you may find that buying a lcd module fitted with an I2C converter saves a lot of i/o pins.

The main disadvantage of the lcd shield is that its position make it difficult to mount the screen and keys in a final project box.

You can buy a SD shield or module, though for early learning you can store your data in Ram and EEprom.


thanks for your reply.

I saw that in several video they are using an Arduino MEGA instead of the UNO. Of course I know that the MEGA has more I/O pins and when you put the shield you will still have several I/O pins free from the board. I also know that it is more powerful re calculation time etc.

I would not mind AT ALL to spend more money for it.

Do you, and in general all of the forum, think might be a better idea for a beginner?

My “orientation” towards the UNO was just because I read online that is the most supported one from the community (programs, troubleshooting, projects, etc.).
I believe this support for a complete beginner is quite important in his learning process.

Any further feedback please?

Thanks a lot.

My view is that you should go with the Uno, as you say it will do almost all the work you will be needing to do in the near future.

The Mega is really for complex projects that may require a vast amount of program memory, or lots of i/o pins that typically a larger tft types of screen /interface board needs.

Forgot to say earlier that you also need a DS3231 RTC module so your readings can be time/date stamped if needed.

You will find a breadboard and connecting wires a good purchase to place things like the sensors and rtc on.

Dear ricki101,

Thanks a lot for your kind help.

I will investigate the DS3231 RTC module because I was not too much aware of it and its use.

Re the breadboard, I appreciate that it is very good to learn how to use it and it might be also comfortable for future project (so I might buy anyway), but for THIS project (in particular) I need the DHT22 to be "free", I mean not plugged in a breadboard, but loose so I could put it inside a little space for example (little box, etc)

Is it still possible to do so or will I have any new issue on the horizon?


If you save your temp readings you will need some method of knowing at what time the readings were taken.

While you can internally run a timer in the Atmega 328 chip , its much better to use a RTC module that does days, weeks etc. plenty of code examples around.

The Uno is fully compatible with all shields and program examples, though a program written specifically for a Mega or the other larger board will have some slight differences, but would not worry about advanced things like that as it will be some time to get to that level.

The Arduino site has plenty of reference material and if you look on Ytube etc there are many beginners tutorial series covering the hardware and C++ ; look at a few and choose one which you find you can follow best.

good luck

Thanks ricki,

I will keep this thread updated with the progress of my project.

It has been very kind of you.