Infrared Remote Control Tester
Surely you had this problem. You tried to change the channel on your TV and nothing happened, but you are not sure if it's the batteries or the remote. Rui built a circuit for testing infrared remote controls.
The circuit is pretty simple but it can turn out to be really useful. To record the IR commands he included a Vishay V34836 IR receiver. He made the PCB with a CNC machine and used a 12F683 microcontroller from Microchip.
The circuit is powered by a couple of AAA batteries and is glued to the battery holder. As you can see in the video above, a red LED lights up when the circuit is switched on and not receiving any IR signal. If it's receiving continuous data the green LED indicates that the remote is fine, and the yellow LED will indicate that the data stream is broken, so the remote is not working properly.
Take a look at our own IR Remote Module.
Infrared Tachometer using Arduino
This project is again simple but very resourceful. [Pinodisco] made a tachometer out of some basic components: a couple of resistors, a motor and wheel assembly and an infrared LED and Phototransistor.
He placed the IR LED and Phototransistor (receiver) facing each other and close, so the receiver can read the signal through the window in the wheel.
He is using an Arduino Due to read the signal from the Phototransistor: the IR receiver is connected to the analog pin A0 in the board, and the IR LED is connected to 5V through a limiting resistor.
Then the code counts the time between two signals from the receiver, it converts the value to rps/rpm and prints it in the Arduino IDE serial monitor.
Read more on Instructables.
Infrared Pulse Sensor
Obviously, this isn't a medical device, but it's pretty amazing. Just like in the projects above it is built around an infrared emitter and detector which are placed close to each other.
This time they are used to detect your pulse. As they explain, when the heart pumps, blood pressure rises and the amount of IR light that gets reflected back to the receiver increases when you press your fingertip against the sensor. So with an amplifier circuitry they can output a signal to the Arduino board.
The signal is taken to the analog pin A0 and then the data can be viewed through the Arduino serial monitor. Finally they even prepared a sketch so you can visualize the data on your computer with Processing.
Check our own medical platform: e-Health Sensor Platform.
Find out more about this step by step tutorial on MAKE