Sometimes you need to know how hot something is, but it just isn't practical to carry around a glass thermometer all the time. With this project, you'll never have this problem again. With the assistance of the two Particle Photons, you can measure temperatures and see the values displayed in real time on the OLED screen.
The Temperature Sensor
One of the Particle Photons is used to run and read data from the temperature sensor. In the code of the temperature sensor, data is converted into temperature readings in Fahrenheit. The code only allows the sensor to run if there is a voltage supply from the other Particle Photon (the OLED screen Photon). If the other Photon is off or the wire connecting the two is disconnected, the temperature sensor quits recording data. There is a grounding wire added to the circuit to ensure that when the wire between Photons isn't there, the temperature sensor turns off. When the wire between the Photon's is connected and the OLED Photon is one, temperature data recorded is sent to the Particle Console Event page and also published to Google Sheets.
View of the Temperature Sensor Setup
As a test to see if the Temperature Sensor was working properly, we let the sensor run for around twenty minutes, recording a reading every five seconds. These readings were published to Google Sheets using an IFTTT applet and then plotted versus time. The apartment temperate was kept at 69 ℉. Based on the data collected the temperature sensor was running properly and experienced small fluctuations in temperature. After testing to see that the sensor worked, the Google Sheets document was left running to record data in real time.
Plot of Apartment Temperature versus Time
1 / 2 • Screenshot of Google Sheets Test Temperature Data
The OLED Screen
The other Particle Photon is used to run the OLED. This Photon is subscribed to the particle console, reading the temperature values published by the other Photon, and displaying them on the OLED screen. This Photon needs to be on for the other Photon to run. Also, if the wire that runs from this Photon to the other Photon (shown in the circuit diagram) is not connected, the temperature sensor will not run. If there is no data on the Particle Console for this Photon to read, the OLED screen displays the last value that is sent to the Particle Console. If both Photon's are running, the Console, Google Sheet, and OLED are updated every second.
View of the OLED Screen Setup