Tri-Temp Project Intro


This is the Tri-Temp project. It comes in two flavors- Standard and Ethernet. The Standard version outputs all readings on an LCD. The Ethernet adds output to HTML via a web browser. I did not design this to use an Ethernet shield- only the Arduino Ethernet- it’s more compact.So what’s this all about? Reading the Temp and Humidity! Nothing special going on here, just reading the digital data from three DHT22 sensors and displaying it.


The project consists of an Arduino Uno (Standard), a project box, a hand hacked breadboard, 4 contact switches, three digital sensors, one analog sensor, an 16×2 LCD with serial interface.

My original idea was to  have a web based “weather monitor”. The Ethernet version covers that but I did the Standard version first. I’ll talk about the features they share first.

Since the Arduino is fairly limited on digital pins and I really wanted a display, I had to find a way to minimize digital pin usage. This meant adding a serial “converter” to the LCD. This reduced its digital pin usage from 7 to 1. Nice save there. Since the project would eventually use Ethernet I had to reserve the higher order pins for that.

The 4 buttons would each need 1 digital pin each, plus 3 digital pins for the temp/humid probes and 1 analog pin for the internal temp.

The 4 buttons allow you to manually scroll through the probes output, change from F to C  (not implemented yet) and turn on/off the display back light.

Since pictures tell more than words you can skip to the bottom to see how it worked out visually. Below is also a parts list with links to suppliers if I could find one.

At the bottom of this post is the code for both versions. They are pretty well documented so if you have questions let me know.

I’m still putting the parts list together….

This is the visual schematic. The pin assignments aren’t necessarily correct.


The v1.0 code is listed separately on this page as it will be updated often.


Here are pictures of the build, more to come…:

0 thoughts on “Tri-Temp Project Intro

  1. Ahh! this is just what I needed. I just got into arduino and after completing some of the learning tutorials I decided to do something very similar to your tri temp project.

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