Welcome to the training module on Handheld Infrared Thermometers . This training module will introduce handheld infrared thermometer knowledge and recommend one solution for it.
An infrared thermometer is a non-contact temperature measurement device. It takes advantage of the fact that all objects emit electromagnetic radiation or energy above absolute zero. This radiation, like X-rays, radio waves, and visible and ultraviolet light is electromagnetic in nature and travels at the speed of light. The higher the temperature of an object, the shorter the wavelength of the peak infrared radiation it emits. It detects the infrared energy emitted by objects and converts the energy factor into a temperature reading.
Infrared thermometers use infrared technology to quickly and conveniently measure the surface temperature of objects. They provide fast temperature readings without physically touching the object. Users simply aim, pull the trigger and read the temperature on the LCD display. Lightweight, compact and easy to use, infrared thermometers can safely measure hot, hazardous or hard to reach surfaces without contaminating or damaging the object. Also, infrared thermometers can provide several readings per second, as compared to contact methods where each measurement can take several minutes.
Infrared thermometers allow users to measure temperature in applications where conventional sensors cannot be employed. Specifically, in cases dealing with moving objects ( i.e., rollers, moving machinery, or a conveyor belt), or where non-contact measurements are required because some applications require users to instantly measure temperature in hard-to-reach areas where users might need a ladder or where the object is hot, rapidly changing temperature, rotating, difficult to reach, energized, or in other dangerous situations (such as high voltage). In harsh environments where fixed or contact thermometers are unable to meet the requirements, a handheld infrared thermometer is the better solution. Besides the industrial applications, infrared thermometers are also used in other field, like fever measurement in medical applications, food quality & safety monitoring in food industry, and a variety of automotive applications.
When selection an infrared thermometer, users will consider about a few of the critical points, including field of view, type of surface being measured, temperature range, target distance, and response time. The field of view is the angle of vision at which the instrument operates, and is determined by the optics of the unit. To obtain an accurate temperature reading, the target being measured should completely fill the field of view of the instrument. The surface type of the target determines the different emissivity values. In general, the higher the emissivity of an object, the easier it is to obtain an accurate temperature measurement using infrared.
A handheld infrared thermometer is composed of optical system, infrared temperature sensor, amplifier, ADC, MCU, LCD display, batteries and DC/DC converter. The optical system collects the infrared energy emitted from the target object within its field of view. The infrared temperature sensor converts the collected infrared energy into electrical signal. This signal will then be amplified and converted by an amplifier and ADC respectively to produce a digital signal. The digital signal will be used by the microcontroller to calculate the temperature of measured object based on certain algorithms, and then display the result on the LCD display.
The infrared temperature sensor detects the infrared energy emitted from the target object. The sensor generates a voltage or current which is proportional to the incident infrared radiation power. According to the considerations we mentioned before, the selection of the IR temperature sensors needs to consider the requirement of application temperature range, field of view, accuracy, and response time. As our solution is a handheld device, the size of the component is also taken into account. At present, the well-known semiconductor companies around the world such as Calex, Perkinelmer, Raytek and GE can provide the infrared temperature sensors for infrared temperature measurement.
If the infrared temperature sensor doesn’t integrate an instrumentation amplifier, a separate instrumentation amplifier is required to amplify the small signals coming from the sensor. As a part of handheld device, the power consumption is one key considerations. Meanwhile, one of the requirements of IR thermometer is accuracy, so the low noise level, low offset and drift parts should be chosen.
The zero-drift INA333 offers the lowest power, lowest input bias current, and best overall voltage offset/drift combination of any low, single supply instrumentation amplifier on the market. Designed with TI’s Zero Drift technology the INA333’s low offset/drift combination makes it ideal for applications requiring the best long term stability achievable. And with a proprietary design technique to attenuate chopping noise, the INA333 also achieves industry leading noise performance in the low power, low offset, instrumentation amplifier sub-market. With a supply current of 75uA that is 10% lower than its closest competition, and being capable of running on a single1.8V supply, the INA333 will be the easy choice for analog designers being pushed for lower power, more efficient solutions. And with only 200pA input bias current, the INA333 also can be used in high impedance applications where low power and low voltage offset instrumentation amplifiers have never gone before.
If the infrared temperature sensor doesn’t integrate an ADC, a separate ADC with high resolution, low power, and small package is required.
A handheld infrared thermometer uses an 8-bit or 16-bit ultra-low-power microcontroller to control the peripheral devices and compute the temperature of target objects. The MCU will read out the sensor output, calculate the result and convert the result into the appropriate format to control the display driver. Nowadays, LCD is common type of display. Therefore, the selected MCU should be integrated with the capability to interface an LCD. To guarantee the longest possible battery life, the MCU should have a low power consumption. For a convenient auto power down function for saving power, firstly the microcontroller will shut down the peripheral and display, then it will go into sleep mode.
S08LL 8-bit segment LCD microcontroller helps you reach your target performance levels while minimizing power consumption in your design, demonstrating extreme energy efficiency for ultra-long operation in battery-powered applications. The S08LL family offers two ultra-low-power stop modes, low-power run and wait modes, six microsecond wake-up time, ultra-low-power external oscillator and clock gating registers to disable clocks to unused peripherals. The family also provides design flexibility with a large segment-based (8 x 24) driver and an integrated charge pump to provide a true system-on-chip.
LCDs are wonderful power-saving displays, and over the last couple of decades technical advancements have confirmed LCDs as the only real option in battery-operated equipment. A small LCD screen is used to display temperature readings, device status, or show operation / functional progress. Based on our application, a monochromic segment LCD meets the requirement.
The tale lists out some additional components which are used in handheld infrared thermometer solutions. The power management part can be a DC/DC converter or LDO regulator that provides a wide range of input voltage, stable output voltage, and low standby current. As it is a handheld device, battery is used as power source which may be a a rechargeable battery with small size, low weight, large capacity and long service life. The battery management parts help to extend battery life. The amplifier is used to amplify the small signals coming from the photo detector.
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Infrared Temperature Sensors Selection Guide R:50K – 20 to +100°C 24ms Thermometrics IR Sensor ZTP-315D1 GE 0-5V – 20 to +150°C 35ms Thermometrics IR Sensor ZTP-25ASM GE R:100K – 20 to +100°C 20ms Thermometrics IR Sensor ZTP-135SR GE R:100K – 20 to +100°C 20ms Thermometrics IR Sensor ZTP-015 GE 0-5V 18 to +538°C 50:1 ±1% noncontact infrared pyrometer Raytek GPS Raytek 0-5V 18 to +538°C 30:1 ±1% noncontact infrared pyrometer Raytek GPR Raytek 0-5V – 0 to +500°C 350ms 4:1 noncontact infrared pyrometer Raytek CI Raytek 0 to +60°C 400ms 49º ±1.5K 4x4 Element Linear Thermopile Array TPA 16T 4146 L3.9 Perkinelmer 0 to +60°C 250ms 50º ±1.5K 1 x 8 Element Thermopile Array TPL 08T 2146 L3.9 Perkinelmer R:50k – 25 to +100°C 100ms 7º ±1.5K Thermopile Sensor with Integrated Processing TPM 1T 0234 M(y ) Perkinelmer R:50-100k – 20 to +100°C 22ms 15º 0.03%/K Thermopile Detector TPD 1T 0226 IRA Perkinelmer R:25-70k – 20 to +105°C 35ms 84º 0.03%/K Single Element Thermopile Detector TPD 1T 0514 PerkinElmer 4-20mA – 0 to +250°C 240ms 2:1 ±1% Infrared Temperature Sensor PE21MT-0 CALEX 4-20mA – 0 to +250°C 240ms 15:1 ±1% Infrared Temperature Sensor PE151MT-0 CALEX 4-20mA – 0 to +250°C 240ms 2:1 ±1% Infrared Temperature Sensor PC21MT-0 CALEX 4-20mA – 0 to +250°C 240ms 15:1 ±1% Infrared Temperature Sensor PC151mT-0 CALEX Sensor Output Temp Range Response Time Field of View Accuracy Description Part Number Manufacturer
Precision Instrumentation Amplifier Selection Guide 135dB 50nV/ √ Hz 25pA 13uV Low Power, Precision, Auto-Zero Op Amp AD8538 ADI N/A 2.1nV/rtHz N/A N/A Low Noise, High Speed Amplifier for 16-Bit Systems AD8021 ADI N/A 2.1nV/rtHz N/A N/A Low Power, Low Noise and Distortion, RRIO Output Amplifier ADA4841-1 ADI N/A 1nV/rtHz N/A N/A Unity-Gain Stable, Ultralow Distortion, High Speed Op Amp ADA4899 ADI N/A 0.95nV/rtHz N/A N/A Low Noise and Low Distortion Op-Amp AD8099 ADI 135dB 140 nV/ √ Hz 1pA 20uV Ultra-Low Offset/Drift, Instrumentation Amplifiers MAX4209 Maxim 135dB 140 nV/ √ Hz 1pA 20uV Ultra-Low Offset/Drift, Instrumentation Amplifiers MAX4208 Maxim 99dB 85 nV/ √ Hz 20nA 50μV Micropower, Single-Supply, RRIO, Instrumentation Amplifiers MAX4196 Maxim 99dB 85 nV/ √ Hz 20nA 50μV Micropower, Single-Supply, RRIO, Instrumentation Amplifiers MAX4195 Maxim 99dB 85 nV/ √ Hz 20nA 50μV Micropower, Single-Supply, RRIO, Instrumentation Amplifiers MAX4194 Maxim 88dB 9 nV/ √ Hz ±200 fA 200 µV Precision, CMOS Input, RRIO, Wide Supply Range Amplifier LMP7701 NS 100dB 35 nV/ √ Hz N/A 50 µV Single, High Precision, RRIO, Operational Amplifier LMP2015 NS 81dB 60 nV/ √ Hz 20 fA 150 µV Low Noise, Precision , RRIO, Operational Amplifier LMP2231 NS 105dB 3.3 nV/ √ Hz ±1.5 nA 500 µV Low Noise, Precision , RRIO, Operational Amplifier LMP7731 NS 100dB 33 nV/ √ Hz 2 nA 100μV Precision, Rail-To-Rail I/O Instrumentation Amplifier INA326 TI 120dB 10 nV/ √ Hz 5 nA 50μV Precision, Low Power Instrumentation Amplifiers INA129 TI 110dB 10 nV/ √ Hz 5 nA 50μV Precision, Low Power Instrumentation Amplifier INA118U TI 90dB 100 nV/ √ Hz 10pA ±200μV Micropower single-supply CMOS Instrumentation Amplifier INA321 TI 106dB 1.1μV/ √ Hz ±70pA 10μV microPOWER CMOS Zero-Drift Series Amplifier OPA333 TI 100dB 50nV/ √ Hz 200pA 20uV Low-Power Precision Instrumentation Amplifier INA333 TI CMRR Noise Bias Current Offset Voltage Description Part Number Supplier
TI INA333 Zero Drift Instrumentation Amplifier
Creates excellent accuracy: Gain Error < 0.1%
Ideal for maximum power efficiency
Easy compatibility for battery powered apps
Great for high impedance applications
Low Noise 1.6 µ V p-p (0.1 to 10Hz)
Enables highest accuracy possible
Enhances noise immunity
Low offset and drift: 20µV (max) with 50nV/C
75µs max Supply Current
Wide Supply Range +1.8V To +5.5V
Input Bias Current : 200pA Max
Input Voltage Noise: 50nV/rt-Hz, 1kHz
CMRR 106db Min at G=100
RFI filtered inputs
RTD Sensor Amplifier
MSOP-8, DFN-8 Package Features Benefits
Low Power ADC Selection Guide SPI 1 12mW 2.8MSPS 12-bit LTC1403 LTC SPI 1 18mW 3.5MSPS 12-bit LTC2356 LTC SPI 1 18mW 3.5MSPS 12-bit LTC2355 LTC SPI 1 10mW 1 MSPS 12-bit ADC121S101 NS I 2 C 1 0.78mW 1 MSPS 12-bit ADC121C027 NS I 2 C 1 0.78mW 1 MSPS 12-bit ADC121C021 NS I 2 C 1 0.36mW 860SPS 16-bit ADS1115 TI I 2 C 1 0.36mW 860SPS 16-bit ADS1114 TI I 2 C 1 0.36mW 860SPS 16-bit ADS1113 TI SPI 1 4mW 100 KSPS 16-bit AD7684 ADI SPI 1 4mW 100 KSPS 16-bit AD7683 ADI SPI 1 3.5mW 1 MSPS 12-bit AD7476 ADI SPI 1 13.5mW 3 MSPS 12-bit AD7276 ADI SPI 1 13.5mW 3 MSPS 12-bit AD7274 ADI Interface No. of Supplies Power Consumption Sample Rate Resolutions Part Number Manufacturer
Low Power MCU Selection Guide IIC/Uart/SPI 6.5uA 8mA Up to 9 Up to 14 4 0.256 N/A 24 CY8C24x23A Cypress IIC/Uart/SPI 6.5uA 8mA Up to 9 Up to 14 16 0.256 N/A 24 CY8C27x43 Cypress IIC/Uart/SPI 10uA 14mA Up to 9 Up to 14 32 2 N/A 24 CY8C29x66 Cypress Uart/SPI 0.1uA 330uA/MHz 54 10 16 1 4*25 16 ATMEGA169P Atmel Uart/SPI 40nA 420uA/MHz 69 10 32 2 4*40 20 ATMEGA3290P Atmel IIC/Uart/SPI 700nA 190uA/MHz N/A N/A 64 2 132 20 MAXQ2000 Maxim SPI/SCI < 15uA 1mA - 20mA -- 10 4 0.256 8*14 / 4*18 Up to 10 RS08LE Freescale SPI/SCI < 1.37 mA < 3.71 mA -- 10 8 0.256 8*21 / 4*25 Up to 10 RS08LA Freescale SPI/IIC/SCI 0.25uA-6uA 0.5mA-5.7mA -- 12 18 to 32 2 4*41 / 8*37 Up to 40 S08LG Series Freescale SPI/IIC/SCI 0.25uA-6uA 0.5mA-5.7mA -- 12 8 to 64 2 to 4 8*36 / 4*28 20 S08LL Series Freescale IIC/Uart/SPI 1.1uA <3.2 mA 12 Up to 16 4 to 120 0.256 to 8 Up to 160 8 MSP430x4xx Series TI Interface Power (Standby Mode) Power (Active Mode) DAC (Bit) ADC (Bit) Flash (KB) RAM (KB) LCD Segments Frequency (MHz) Part Number Manufacturer