« Build ideas: Did I turn the stove off??

Of course, the stove was turned off. That’s what I thought, I just couldn’t remember explicitly doing it. Now we are behind schedule and most likely won’t arrive at the campsite until it’s already dark.

Step 2

After setting this up the next step is to try and get a temperature reading in the console. From the datasheet, we see that the address we need to read from is 0x07 (Tobj1) – the Temperature of the Object

In bash we need to run

i2cdetect -y 0

to get the Address of the i2c Bus. In my case, it was 0x5a. We can then read the Raw temperature data in python with:

import smbus
bus = smbus.SMBus(1)
word = bus.read_word_data(0x5a, 0x07)

The number we are receiving is word data, and we need to convert it to Fahrenheit, this is how I did that:

kelvin = word * 0.02
celcius = kelvin - 273
fahrenheit = (9 / 5 * celcius) + 32

Awesome! Running this program gives us a Fahrenheit temperature reading and it is room temperature! The next thing I did was to make a hot cup of tea and hold it over the temperature sensor and take another reading. It should be much greater than room temperature if everything is setup correctly!

Step 3

Our next step is to design a system using nio that will take a reading every 5 seconds and publish that data to a socket server.

In order to do this we need to create a simple Infrared Thermometer block. The first step is to clone down the nio Block Template, I named mine irthermometer_block. The next step is to use the commands we wrote above in order to get the temperature and pass that signal on.

Once that block is installed we can simply import it into nio and process a signal every 5 seconds and publish that to a socket server.

Step 4

The next piece is to install the actual temperature sensor on the stove! We need to have it connected to the RaspPi still so the best solution I found was to extend the 4 wires and have just the sensor hang over the stove while the electronics sit above the kitchen cabinets, far away from the electronic damaging steam that comes from the stove.

Step 5

The last step is to setup our socket server and output data to a url! For this project I setup a subdomain stove.aaronranard.com. I created and styled a small socket.io server to capture the data and display the UI.

For this implementation, we need to store previous temperature readings so we can know if it is going up, down, or staying relatively even.

The biggest use-case for checking if you turned your stove off is about 5 – 10 minutes after you’ve left home. In this situation, the stove might still be hot, BUT it should be cooling down.

So we need to show more than the exact temperature reading because if I were to view it right after I left and it said 130 I may think I left it on, whereas, in reality, it is just cooling down.

const halfLength = valuesToStore / 2;
const oldData = previous.slice(0, halfLength);
const newData = previous.slice(halfLength);

const oldAvg = oldData.reduce((total, data) => { return total + parseFloat(data.fahrenheit) }, 0) / halfLength;
const newAvg = newData.reduce((total, data) => { return total + parseFloat(data.fahrenheit) }, 0) / halfLength;