This is a small project to get you started with the electric imp and a Thermistor so you can see how you can get temperature readings updating live on a web site. This instruct able will address both the hardware and the web site along with all the parts in between. I’ve tried to keep it as simple as possible which means there are plenty of ways you can expand on it.
The first part will address the electric imp and how we connect a resistor and Thermistor to create a very simple circuit called a voltage divider and use the imp’s built in analog to digital converter to take a reading and calculate what the temperature is. I’ll also go into some detail on how the circuit and it’s components work.
We’re going to create a voltage divider network using a 10k resistor and the 4.7k Thermistor. The Imp will read the voltage between the resistor and thermistor. The Imp then does some calculations on this and stores the value. It does this 50 times every 5 seconds (or there about) to get an average reading. This average reading is sent to HTTP Request node (which lives in the Amazon Cloud) which in turn sends it to your web server.
Your web server receives this as parameters attached to the URL, logs it, and displays the result.
You’re going to need the following:
• electric imp
• Sparkfun electric imp Breakout (April board)
• Thermistor – NTC 4.7Kohms 2% Radial as the temperature sensor.
• 10k ohm Resistor 1% 1/4W
• Some connectors (I used):
o Stackable Header – 1 x 10 – Standard as it allows me to plug into a breadboard, but also access from the top.
o Break away headers – straight – brake off three pins for the jumper connection to select
Read More: Simple wireless temperature sensor updating