A thermal camera module for Arduino adds a remarkable sensing capability to your projects — the ability to see heat. Thermal cameras detect infrared radiation emitted by all objects above absolute zero and convert it into a temperature map or thermal image. For electronics work, this means instantly spotting overheating components, short circuits, and power dissipation issues without contact. For IoT and automation, it enables people detection, fever screening, and environmental monitoring. This guide covers the three main thermal camera modules available to Indian hobbyists: the AMG8833, MLX90640, and FLIR Lepton.
Table of Contents
- How Thermal Cameras Work
- AMG8833: The Entry-Level Module
- MLX90640: The Sweet Spot
- FLIR Lepton: Professional Quality
- Using Thermal Cameras for Electronics Debugging
- Project Ideas
- Module Comparison Table
- Frequently Asked Questions
- Conclusion
How Thermal Cameras Work
Every object with a temperature above absolute zero (-273.15°C) emits infrared radiation. Warmer objects emit more infrared energy than cooler ones. A thermal camera uses a microbolometer array — a grid of tiny sensors that change resistance when they absorb infrared radiation — to measure the temperature of each pixel in its field of view.
The output is a temperature array: each pixel represents a temperature value, not a colour. The false-colour images you see (red for hot, blue for cold) are created by mapping temperature values to a colour palette. The camera does not “see” heat in colour — it measures temperature and software applies the colour mapping.
Thermal cameras differ from regular cameras in important ways: they have much lower resolution (64 pixels vs millions), they work in complete darkness, they cannot see through glass (glass is opaque to infrared), and they measure surface temperature only (they cannot see inside objects).
AMG8833: The Entry-Level Module
The Panasonic AMG8833 (also known as Grid-EYE) is an 8×8 pixel thermal sensor array — 64 temperature-sensing pixels arranged in a grid. It is the most affordable thermal imaging module available, making it the entry point for most hobbyists.
Specifications:
- Resolution: 8×8 pixels (64 temperature points)
- Temperature range: 0°C to 80°C (can detect -20°C to 100°C with reduced accuracy)
- Accuracy: ±2.5°C (typical), ±4.5°C (maximum)
- Field of view: 60° x 60°
- Frame rate: 1-10 FPS
- Interface: I2C (address 0x68 or 0x69)
- Operating voltage: 3.3V (most breakout boards include a 3.3V regulator for 5V compatibility)
- Price in India: ₹2,000-3,000
Capabilities: With 8×8 pixels, you get a very coarse thermal image — enough to detect the presence and approximate location of heat sources, but not enough for detailed thermal analysis. It can detect a person in a room, identify which component on a PCB is hottest, and measure approximate surface temperatures.
Limitations: 64 pixels is very low resolution. You cannot distinguish between two components that are close together. Temperature accuracy of ±2.5°C is insufficient for precise measurements. It works best as a human presence detector or a coarse thermal scanner.
MLX90640: The Sweet Spot
The Melexis MLX90640 is a 32×24 pixel thermal sensor array — 768 temperature-sensing pixels. This is the most popular thermal camera module for serious hobby and semi-professional work, offering a dramatic improvement over the AMG8833.
Specifications:
- Resolution: 32×24 pixels (768 temperature points)
- Temperature range: -40°C to 300°C
- Accuracy: ±1°C (in the 0-100°C range)
- Field of view: 55° x 35° (BAA variant) or 110° x 75° (BAB variant)
- Frame rate: 0.5-64 FPS (higher FPS = lower resolution per frame due to subsampling)
- Interface: I2C (default address 0x33)
- Operating voltage: 3.3V
- Price in India: ₹4,000-8,000
Capabilities: 768 pixels is sufficient to create recognisable thermal images. You can identify individual components on a PCB, detect hot spots on motor controllers, see people through a doorway, and monitor temperature distribution across a surface. The 300°C upper range covers most electronics debugging scenarios.
Programming: The MLX90640 communicates over I2C and requires reading 832 words of data per frame, followed by complex calculations to convert raw data to temperature values. Libraries are available for Arduino (SparkFun MLX90640 library) and Raspberry Pi (Pimoroni mlx90640-library). The Arduino Uno’s limited RAM makes it challenging — an ESP32 or Raspberry Pi is recommended.
FLIR Lepton: Professional Quality
The FLIR Lepton is a miniature thermal camera core used in products like the FLIR ONE smartphone attachment. It offers near-professional thermal imaging at a fraction of the cost of a standalone thermal camera.
Specifications:
- Resolution: 80×60 pixels (Lepton 2.5) or 160×120 pixels (Lepton 3.5)
- Temperature range: -10°C to 140°C (radiometric versions up to 450°C)
- Accuracy: ±5°C or ±5% (whichever is greater)
- Field of view: 51° (horizontal) x 63.5° (vertical)
- Frame rate: 8.6 FPS (due to ITAR export restrictions on higher frame rates)
- Interface: SPI for video, I2C for control
- Price in India: ₹15,000-30,000 (module only, harder to source domestically)
Capabilities: The Lepton produces thermal images that are detailed enough for professional electronics debugging, building energy audits, and medical screening applications. The 160×120 resolution of the Lepton 3.5 creates clear thermal images with identifiable detail.
Challenges: The Lepton uses a specialised connector and requires a breakout board (PureThermal or GroupGets). It is more complex to interface than I2C-based sensors. Availability in India is limited — most hobbyists import from the USA or use the FLIR ONE smartphone attachment instead.
Using Thermal Cameras for Electronics Debugging
Thermal imaging is an incredibly powerful debugging tool for electronics:
Finding short circuits: Power up a board with a suspected short circuit through a current-limited supply. The shorted trace or component heats up and is immediately visible on the thermal camera. What could take hours of probing takes seconds with thermal imaging.
Identifying overheating components: Run your circuit under load and scan with the thermal camera. Voltage regulators running hot indicate insufficient heatsinking or excessive current draw. Hot ICs may indicate design issues or counterfeit components.
Power supply analysis: Visualise heat distribution across a power supply PCB to identify inefficient components, undersized traces, and poor thermal design. MOSFETs, diodes, and inductors should run warm (40-60°C) but not hot (80°C+).
Solder joint inspection: Cold solder joints sometimes show different thermal behaviour under current flow. A high-resistance cold joint heats up more than a good joint carrying the same current.
Thermal management verification: After adding heatsinks, fans, or thermal pads, use the thermal camera to verify that they are actually working. A heatsink that is not properly coupled to the chip shows a cool heatsink and hot chip — obvious on thermal imaging.
Project Ideas
1. PCB thermal scanner: Mount an MLX90640 on a servo-driven pan-tilt mechanism. Scan a PCB automatically and generate a thermal map overlaid on a photograph of the board. Identify hot spots for design review.
2. Room occupancy counter: An AMG8833 at a doorway detects warm bodies passing through. Count the heat blobs entering and exiting to maintain an occupancy count. Useful for COVID-era capacity management in Indian offices and shops.
3. Non-contact thermometer display: Mount an MLX90640 at an entrance with an LCD display. Show a thermal image with the maximum detected temperature displayed prominently. More informative than a single-point infrared thermometer.
4. Night-vision security camera: Combine a thermal sensor with a Raspberry Pi and a regular camera. The thermal sensor detects heat sources (intruders, animals) even in complete darkness and triggers the visible-light camera for identification.
5. 3D printer bed leveling: Use a thermal camera to visualise temperature uniformity across a heated 3D printer bed. Cold spots indicate levelling issues or heater element problems. An AMG8833 is sufficient for this application.
Module Comparison Table
- AMG8833: 8×8 pixels | 0-80°C | ±2.5°C | I2C | ₹2,000-3,000 | Best for: presence detection, coarse thermal scanning
- MLX90640: 32×24 pixels | -40 to 300°C | ±1°C | I2C | ₹4,000-8,000 | Best for: electronics debugging, people detection, thermal analysis
- FLIR Lepton 3.5: 160×120 pixels | -10 to 140°C | ±5°C | SPI+I2C | ₹15,000-30,000 | Best for: professional thermal imaging, detailed analysis
Frequently Asked Questions
Can a thermal camera module detect fever accurately?
The AMG8833 (±2.5°C accuracy) is too imprecise for fever screening — a 0.5°C fever cannot be reliably distinguished from normal body temperature. The MLX90640 (±1°C) is borderline. For medical-grade fever screening, dedicated medical thermal cameras with ±0.3°C accuracy and blackbody reference are required.
Can thermal cameras see through walls or clothing?
No. Thermal cameras see surface temperature only. They cannot see through walls, clothing, or any solid material. They can detect temperature differences on surfaces — such as warm spots on walls indicating poor insulation or hidden pipes.
Which module works best with Arduino?
The AMG8833 works well with Arduino Uno (64 pixels is manageable in RAM). The MLX90640 requires more RAM and processing power — use an ESP32 or Raspberry Pi. The FLIR Lepton is best paired with a Raspberry Pi or a powerful microcontroller.
How far can these modules detect heat?
Detection range depends on the target size and temperature difference. The AMG8833 can detect a human body at 5-7 metres. The MLX90640 detects a person at 10-15 metres. For electronics debugging, you typically work at 5-30 cm distance for useful detail.
Is the FLIR ONE smartphone attachment a good alternative?
For casual thermal imaging, the FLIR ONE (₹20,000-30,000 in India) is excellent. It offers higher resolution than the MLX90640, built-in visual camera overlay (MSX technology), and a polished smartphone app. However, it cannot be integrated into Arduino/ESP32 projects — it works only with smartphones.
Conclusion
For most Indian hobbyists, the MLX90640 (₹4,000-8,000) offers the best balance of resolution, accuracy, and price. Pair it with an ESP32 for a powerful, standalone thermal imaging tool. The AMG8833 (₹2,000-3,000) is perfect for presence detection and coarse thermal scanning. And the FLIR Lepton is the choice when you need near-professional thermal imaging quality.
Explore thermal imaging modules and sensors at Zbotic to add heat-vision capability to your projects.
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