Living in Florida, I was interested in creating a garment that could warn me when it got too hot outside. Using Arduino and a few simple components I was able to create a circuit board that could be incorporated into a headband which warns me when the temperature reaches a specified point, in this case 30C, or 78F.
Step 1: The Parts
The parts which are required to complete this build include:
1) An Arduino Uno
2) Empty Circuit Board
3) TMP36 Sensor
4) Connector pins
8) Sewing supplies/needle, thread etc.
9) 9v battery
Step 2: The Wiring Diagram
For the project to work properly, and ensure that it was wired correctly, I tested out my plan in Fritzing first. The following schematic will serve as a template for placing the components later. Note: in my case, I simplified the final project even further. Instead of manually wiring the 9V battery into the Vin and GND on the Arduino board, I spliced a 3.5mm input and powered it that way. I mention this now to avoid any confusion later should you decide to create this whimsical project yourself.
Step 3: Code
To code this project, I used information from Mecabot's website listed below. However, I will also post the code here for ease.
int Sensor = 0 ;
//float temp = (5.0 * analogRead(A0) * 100.0) / 1024;
int lectura = analogRead(Sensor);
float voltaje = 5.0 /1024 * lectura ; // Atencion aqui
// Si usais un LM35DZ vuestra formula sera
//float temp = voltaje * 100 ;
float temp = voltaje * 100 -50 ;
tone(7, 494, 500);
tone(7, 494, 500);
Step 4: Test It Out
To make sure the proof of concept worked, I built the project before soldering on the components making them permanent. In this example, I hard wired in the 9v battery into the Vin and GND areas on the Arduino, just like the schematic.
Step 5: Connector Pins
After your test circuit works properly, your next step is to build the final version with permanent solder points. To reduce the number of wires I used small connectors on a circuit board that I laid directly on top of the Arduino. This step shows the small connectors in place before I put the circuit board on top. I am showing you two different views so you can see where the connector pins go.
Step 6: Elongate Wires
In this project I wanted to make the temperature sensor look like an antenna. To achieve this, I elongated the contact points by adding about 8" of wire, as seen in the photo. Note: be sure that the contact points on the TMP36 sensor do not get soldered together. To prevent this, I added some insulating material as seen in the close up. This entire step is not necessary for the project to work, only if you intend on making an antenna for your build.
Step 7: Soldering
Next place the circuit board on top of the pins placed in the previous step and solder the components in place as seen in the picture. At this time, you can solder in the speaker wires and TMP36 wires.
Step 8: Testing
It is a good idea to test the project one more time before going any further. Once the previous step is completed, your project should look similar to the one here. The video demonstrates the functionality, and proof that it is working properly.
Step 9: Assembly
Now that the project is soldered and working properly, you can start enclosing it into and garment that you like. For me, I thought a headband worked well so I started to sew a pouch for the electronic components to fit into. Then, I sewed the antenna part on separately.
Step 10: Final
Here is a photo of the final product. I think it worked out just fine. Even though the antenna isn't necessary I think it gives the project a humorous overtone and makes it fun!