Arduino "Talking" Temp / Humidity on a TFT LCD w/ relays

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From the minds of

UPDATE: Added our SpeakEasy Text-To-Speech (TTS) Shield to make this a "Talking" Weather Station!

UPDATE: Added a 4 port relay board for device control

UPDATE: Added Dew Point and Heat Index calculations

SainSmart sent me a 1.8" TFT LCD (ST7735R), and I decided to upgrade my Weather Station / Thermostat. This time around, I used the slightly less accurate but much less expensive DHT-22 (AM2302) temperature / humidity sensor. I also received a BMP-085 barometric pressure sensor, but it appears dead. More on that in the near future. Tighten your seat belt, and here we go:


Arduino Uno
10k Ohm Resistor
Relay Board (optional)
Male / Female Jumpers (very helpful)

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Step 1: Connections

Picture of Connections
Connect the DHT-22 sensor and the LCD display as per the schematic. There are also connections on the left side of the display for the SD card, and we will address that at a future edit for logging purposes. Just use the connections on the right side of the display for now.


(S)ignal to Arduino Pin 2
+5 to Arduino +5vdc
G to Arduino Ground
10k Resistor between S and +5vdc

ST7735R LCD:

VCC to Arduino +5vdc
Gnd to Arduino Ground
SCL to Ardiuino Pin 13
SDA to Arduino Pin 11
CS to Arduino Pin 10
DC to Arduino Pin 9
Reset to Arduino Pin 8

Hi. I was wondering if you can help me. I am planning on using this (minus talking part) for a homemade incubator. Am trying to set-up the code, but I get an error. The part hi-lighted is "DHT dht(DHTPIN, DHTTYPE);" with the error "'DHT' does not name the type." I would be grateful for your thought, as search this problem has come up with no easy fix.

Great and inspiring instructable!

sspence (author)  madmoonfish4 days ago
Sounds like you are missing the dht library.

Aargh! I thought they were ok as they were showing up in my library. I even tried 3 different DHT libraries previously (which all showed up!) So what did was updated my arduino software to current version. Re-done the dht sensor files and now all works fab! Thanks very much! Just need to setup my relays and all will be up and running. Thanks again :D

kurtee8 months ago
Ok, something seems to be wrong!
You are showing CS, DC an RST to be pins 10,9 and 8.
In your code CS=10, DC=11 and RST =13
Also ,are the SCL clock and SDA data line coded from the libraries.
When I scope 13 it does not seem to be reset because it popping like a clock signal!
Very confused!!
sspence (author)  kurtee8 months ago
Good catch. Originally, we did software SPI (any pins can be used), then switched to hardware SPI (for faster performance), and forgot to update parts of the instructable. All should be fixed now.
dleec45 sspence4 months ago
Do I need to call the different code examples any particular name....kinda new at this...thanks
sspence (author)  dleec454 months ago
any name you would like, within arduino naming conventions.
dleec45 sspence3 months ago
Ask previous question about naming requirements of programs as haven't done this much and now I'm confused with how do you load all 4 programs to get everything to work? Any help appreciated...thanks
sspence (author)  dleec453 months ago
to load a sketch on an arduino, you use the arduino IDE, open the sketch to upload or type the code, and click the upload button. you can only have one sketch loaded at a time. Learning to use the Arduino IDE is beyond the scope of this tutorial. See
dleec45 sspence3 months ago
Thanks sspence for the reply....I do understand that only one sketch can be loaded at a time but I'm trying to use all the features of this project with the relay and don't know how one accomplishes this.....any suggestions?
sspence (author)  dleec453 months ago
yes, you add the various features to one big sketch, like I did in the tutorial.
dleec45 sspence1 month ago

I've looked at doing this but I'm just not a programmer so I don't know how to pull this off.....thanks for your replies

ramzi bash4 months ago
tank you veryyyyyyyyyyyyyyy much
kurtee8 months ago
That did the trick!
Glad to see that my display is working properly.
Many thanks for the write up!
sspence (author)  kurtee8 months ago
Sorry for the confusion. I need a version control system :-)

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