2023 Health-STEM Camp: 

Heath and Coding: July 24 to July 28  |   9:00 to 12:30
Lessons: ​

Materials for this activity: 

Gas Sensor MQ135
Jumper Wires
Arduino and USB Connector
Breathing Barrier
22 kΩ Resistor
OLED
Breadboard

CO2 in the air 

The earth’s Atmospheric CO2 level is increasing year over year. The global average atmospheric carbon dioxide in 2019 was 409.8 parts per million and it was 411.3 ppm in October 2020. Carbon dioxide is a key greenhouse gas and responsible for about three-quarters of human emissions. So CO2 level monitoring has gained importance.

Wiring Diagram

For the first CO2 activity, we are only using the A0 signal pin. Let's wire it up. 

The Base Code

We are going to start simple. We are not going to calibrate it and just take its preprocessed output data and display it to the serial monitor. Type up and send out this code after you wire up your sensor to the board. After you upload it, open up the serial monitor. 
It should have outputs like this. 
​Did it work? If it did, save your code. 

Outputting Readings to OLED

Wire up the OLED with the gas sensor. Below is how to wire that if you forgot. Change the code to below and see if you can get the readings from the sensor to get sent to the OLED. 
The Wiring. 
1) GND to GND 
2) VCC to 5 V
3) SCL to pin A5
4) SDA to pin A4
This lesson is inspired by 
https://circuitdigest.com/microcontroller-projects/interfacing-mq135-gas-sensor-with-arduino-to-measure-co2-levels-in-ppm

and https://pslab.io/blog/measuring-co2-with-mq135/

https://www.hackster.io/sheekar/mq-135-sensor-co2-benzyne-with-arduino-sheekar-banerjee-ab6ccd​

Proximity Sensor

IR obstacle sensor - is something in front of me? 

This sensor's only job is to tell if something is in front of it or not. It is easy to wire to the Arduino. See the picture to the right to see how to wire it. 
The clear LED is an IR lightbulb. The dark bulb is an IR phototransistor. Photoresistors are devices that amplify current more when more light shines on it. The sensor works by emitting light in front of it and then the detector measures the amount of light reflection. The little screw on the board is a variable resistor that you can use to set the detection threshold. If the detector receives enough light, it outputs that something is there! 

Plug the sensor into the Arduino. Then point a digital camera, like your cell phone or webcam, at it and see if you can see the light using the camera. Note, only some cameras can see IR. 
The bulb not emitting visible light. It is only emitting a specific wavelength of infrared light (IR)! That means it is not visible to your eye.

Look at this picture and video for how this sensor works. 

The code!

This sensor gives outputs of either 0 or 1 for if something is close to it or not. This code below will print on or off to the Serial Plotter depending on if something is close to it or not. Type out the code below in Arduino IDE
Upload the code and open the serial monitor and see if it works! 

Go Beyond!

Differentiation day: Students get time with teachers to catch up on activities from earlier this week if they could not finish them. Students that are ahead can try our optional lessons or look through tutorial books and learn how to do more at their own pace.
Here are some of the built in examples the Arduino program comes with: 
https://www.arduino.cc/en/Tutorial/BuiltInExamples

Here is a book if you are interested in other activities that we did not learn this week. Your kit has many of the parts needed for these, but not all. There are many Amazon Prime Arduino stores where you can get other supplies. 
the_most_complete_starter_kit_for_uno_v1.0.17.1.13.pdf
File Size: 31153 kb
File Type: pdf
Download File
Some lessons that you may want to try. 
Joystick to control a motor: https://toptechboy.com/arduino-tutorial-39-using-a-joystick-to-control-dc-motor-speed-and-direction/ 

Controlling a multicolor LED: 
​https://create.arduino.cc/projecthub/Raushancpr/control-rgb-led-with-joystick-68f601

​Students, fill out this form for proof of enrollment

https://formstack.io/70035

Show and Tell

At 12:00 parents are invited to our classroom (158 and 159) for a short show-and-tell where students can share the things they designed on the computer and built. Mr. Dorsey will share other regional STEM opportunities your family can consider when your students get older. 

It's time to prep for the show! 

Check that all your electronics and code work for what you want to share for the ending presentation and set up anything else you were able to make.  Finalize what you want to show your teachers,  the other students, and parents. 

​Your spaces should be cleaned and ready to present by 11:45.
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