Tag Archives: IR

Non-Contact Body Temperature Meter

One of the most commonly used medical instruments nowadays is the thermometer. The thermometer is used to monitor or measure the body temperature of a sick person. The idea of creating a thermometer started from a device called thermoscope, a thermometer without a scale. Several inventors developed it until Sir Thomas Allbutt invented the first practical 6-inch medical thermometer able to sense a body temperature in five minutes. The development of the thermometer did not stop there and today, digital thermometer exists which is faster and very accurate.

This reference design is an example of a low cost non-contact digital thermometer. It only uses a microcontroller, a four digit seven segment display and an infrared (IR) temperature sensor. The concept of this design is to make the IR sensor measure the temperature of the thermal radiation emitted by the body being measured. The data acquired by the sensor will be sent to the microcontroller through the I2C bus. The microcontroller will analyze the data and then shows the body temperature on the four-digit seven-segment display.

The circuit of this reference design uses few components only and is very easy to understand. However, to make the circuit function accurately, software calibration must be implemented carefully. The whole circuit is powered by a 5V DC power supply regulated from the four 20mm coin shape batteries contained in a 120591-1 TE Connectivity battery holder. The batteries are connected in series-parallel connection to produce a 6V 480mAh source of power. With the help of a low-dropout voltage regulator, the 6V is regulated to a 5V DC supply

Non-Contact Body Temperature Meter – [Link]

Passive Infrared Detector Circuit

The infrared (IR) is invisible radiant energy, electromagnetic radiation that we cannot see with our eyes, but we can sometimes feel on our skin as heat. The infrared light falls just outside the visible spectrum, beyond the edge of what we can see as red. Most of the thermal radiation emitted by objects near room temperature is infrared.

The circuit uses a MCP6032 microchip operational amplifier. The MCP6032 operational amplifier (op amp) has a gain bandwidth of 10kHz with a low typical operating current of 900nA and an offset voltage that is less than 150uV. The MCP6032 uses Microchip’s advanced CMOS technology, which provides low bias current, high-speed operation, high open-loop gain and rail-to-rail input and output swing. The MCP6032 operates with a single supply voltage that can be as low as 1.8V, while drawing less than 1uA of quiescent current. The MCP6032 is available in standard 8-lead SOIC and MSOP packages. It also includes, a PID20 integrated circuit and a few electronic components. The size of the output signal of PID20 is determined by the task at pins 3 and 4. The output signal at pin 3 is compared with a reference voltage equal to half the supply voltage. The reference voltage is taken from the voltage divider R2-R3-R4-R5. When approaching an object warmer than the surrounding environment, or to remove an object colder than the environment, the output voltage increases. The variation of the sensor output will be compared, the IC2a and IC2b, located voltage of 0.5V under and over voltage reference respectively. Depending on the output, one of the comparators calculates and activates T1.

This basic circuit is used in night-vision devices with infrared illumination, which allows people or animals to be observed without the observer being detected. The infrared light is also used in industrial, scientific, and medical applications as well as in consumer devices.

Passive Infrared Detector Circuit – [Link]



4 Channel Infrared (IR) Remote is a simple project using the popular  HT12A and HT12D encoder / decoder chips from Holtek.


  • Supply – Transmitter: 2.4 ~ 5 VDC, 5 V @ 20 mA & Receiver: 5 ~ 6 VDC, 5 V @ 50 mA
  •  Output – 4 Latched/Momentary TTL compatible outputs
  •  Crystal based oscillator for reliability of operation
  •  DIP switch selectable 8 bit address code
  •  LED output to indicate reception
  •  ON/OFF slide switch in the transmitter
  •  Power-On LED indicator in the Receiver / Transmitter
  •  High noise immunity
  •  Berg connector for interfacing of the board
  •  Four mounting holes of 3.2 mm each
  •  PCB dimensions – Transmitter: 61 mm x 47 mm & Receiver: 46 mm x 46 mm


DIY Infrared Remote Controls


by Jason Poel Smith @ makezine.com:

Halloween is the perfect opportunity to create fun special effects. When you want to be able to control props and effects remotely, one good option is to use an infrared remote control. In this project, I’ll show you some simple remote controlled effects that you can set up in your haunted house this year.

DIY Infrared Remote Controls – [Link]

Simple Infrared Barrier


by Maurizio @ dev.emcelettronica.com:

Although a remote control is not so difficult to design and build, there is an even simpler option: the IR barrier. This consists of a constant IR signal permanently going from an emitter to a receiver, both of them being in two different places (a few meters apart). When an obstacle comes in between the emitter and the receiver, the IR signal is blocked and the receiver senses that it is missing, flagging the event in an appropriate manner (figure 1).

The principle of operation is simple enough, and with most components taken off the shelf, it is easy to design the schematic. The IR element in the emitter is a simple IR LED. This behaves absolutely like any other LED, with the sole exception that it emits light in the infrared spectrum. The emitted light is thus invisible to human eye, but it is meant to excite the infrared receiving element on the other side of the barrier. One important element of this LED is the wavelength of the emitted light, of which we already know that is in the infrared spectrum.

Simple Infrared Barrier – [Link]

Simple Infrared PWM on Arduino, Part 3


The crew from AnalysIR has written up an article on Simple Infrared PWM on Arduino. If you missed part 1 and part 2, be sure to check it out.:

In Part 1 of this series, we demonstrated how to send signals using soft or Simple Infrared PWM on Arduino. In our Part 2 post we looked at sending RAW IR signals – specifically a RAW NEC signal and a longer RAW Mitsubishi Air Conditioner signal using soft PWM. We have since improved the PWM method shown in Part 1 & Part 2 to provide better performance and improve portability. In this Part 3, we will take the signals from Part 2 and show how to send them using their binary (or Hex) representation, which can save lots of SRAM in many projects, particularly when dealing with longer AC signals.

Simple Infrared PWM on Arduino, Part 3 – [Link]

Controlling servo motor using IR remote control

by mohamed soliman @ instructables.com:

If you are looking for comfort and controlling your electronic devices remotely, you will find your need in this instructable.

In this instructable we will learn how to control a servo motor with remote control, this will give you a general concept on how to control remotely. You should know that the remote control sends Infrared(IR) signals, so we will learn how to receive and read these signals using Arduino.

Controlling servo motor using IR remote control – [Link]

IR remote tester


Who never had the need to test a TV or DVD remote?

I have several times. My favorite technique was to take my mobile phone and with the camera pointed at the infrared emitter look for a flashing little purple light. The mobile phone technique is an way for testing the remote but still i decided to make a small circuit just to test the remotes.

IR remote tester – [Link]

Simple, easy and cheap wireless presenter


by Dimitris Platis @ instructables.com:

During presentations, I avoid being stationary and generally like to walk around in order to increase the interaction between me and the audience. However, I am constantly being faced with the burden of having to go back to the laptop, in order to change a slide or tell a person sitting by the laptop to do that. Not cool!

This problem is usually solved by devices, called remote clickers or wireless presenters, which consist of a handheld controller with buttons that sends signals to a USB dongle plugged in the computer. After looking around to buy one, I could not find any decent option costing less than 10$. So why not make one?

Simple, easy and cheap wireless presenter – [Link]

Simple Infrared PWM on Arduino


by analysir.com:

We are often asked on discussion boards, about conflicts between IRremote or IRLib and other Arduino Libraries. In this post, we present a sketch for ‘Simple Infrared PWM on Arduino’. This is the first part in a 3 part series of posts. Part 1 shows how to generate the simple Infrared carrier frequency on Arduino, using any available IO pin and without conflicting with other libraries. Part 2 will show how to send a RAW infrared signal using this approach and Part 3 will show how to send a common NEC signal from the binary or HEX value.

Simple Infrared PWM on Arduino – [Link]