IoTClass Inside the measurement
A closer look · 01

Sensor

Look inside
a sensor.

Infrared thermopile

In the MLX90614, the infrared detector signal is amplified and converted, then combined with a measurement of the sensor's own temperature to calculate object temperature.

The course describes thermal imaging arrays as grids of thermopile elements that produce temperature maps. This explorer focuses on a single sensor.

Test the chosen part in its installed position and expected temperature range: placement can change whether a reading is useful.

01

Recognize the element

Recognize the element: Infrared thermopile

Thermopile: radiation to temperatureInfrared enters a conceptual thermopile can. Absorption warms sensing junctions relative to reference junctions and generates voltage. Signal conditioning leads to a temperature estimate. Functional arrows are not wiring; no internal construction is depicted. Conceptual infrared thermopile elements Signal Conditioning temperature
The infrared detector signal is processed with the sensor temperature to calculate object temperature.
02

Peel the teaching model

From case to sensing element

Choose a layer to see the measurement path. The enclosure and board layout are invented teaching choices, not a particular product.

The full text version below describes every layer. All measurement explanations are available without 3D.
Conceptual, not to scale
Case: metal can and infrared windowThe MLX90614 contains a thermopile detector and electronics that amplify and process its signal inside a metal can. [MLX90614: General description]

Drag to rotate; pinch to zoom. With the view focused: arrow keys rotate, + / − zoom, 1–3 choose a layer, Home resets rotation and zoom. Step advances to the next layer; Reset returns to the case and default view. Layer buttons select a view directly. The page does not move on its own.

Layer 1 of 3 / Outside

Case: metal can and infrared window

The MLX90614 contains a thermopile detector and electronics that amplify and process its signal inside a metal can. [MLX90614: General description]

Teaching view: The simplified metal can has a dark infrared filter and leads. Package details and internal construction are illustrative.

The measurement to rememberThe MLX90614 estimates an object’s temperature from infrared radiation exchanged with it. The reading depends on how well the surface emits infrared radiation, called emissivity, and how much of the sensor’s viewing area the object fills. [MLX90614: General description]

Full text version · every layer

1 · Case: metal can and infrared window

The MLX90614 contains a thermopile detector and electronics that amplify and process its signal inside a metal can. [MLX90614: General description]

Teaching view: The simplified metal can has a dark infrared filter and leads. Package details and internal construction are illustrative.

2 · Board / module: detector and readout

The detector voltage is amplified and converted into digital data. The electronics use that data and a separate measurement of the sensor’s own temperature to calculate object temperature. [MLX90614 §4.1: Functional description]

Teaching view: The detector chip and readout chip sit inside the same can and connect through internal wires. Their arrangement is simplified for teaching.

3 · Element: absorber and thermocouple junctions

Absorbed infrared radiation changes the temperature of thermocouple junctions on a thin membrane relative to junctions on the chip body. This temperature difference produces a small voltage. Connecting many thermocouples in series adds their voltages. The illustrated arrangement is simplified. (See MLX90614 §4.1.8, page 29.) [MLX90614: General description]

Teaching view: The conceptual dark absorber carries gold junction strips and connects by gold bond wires. Their count and layout are illustrative, not a documented MLX90614 cross-section.

Explore the layers in order to follow the teaching model.

03

Listen

Package narration

Read transcript
Maya is choosing a sensor for a room monitor. She finds a thermopile and asks how its signal becomes a temperature reading. In the MLX90614, the infrared detector signal is amplified and converted, then combined with a measurement of the sensor's own temperature to calculate object temperature. Maya first assumes that any thermal sensor will give her a temperature image. The course describes thermal imaging arrays as grids of thermopile elements that produce a temperature map. This explorer focuses on a single sensor. She must choose the kind of output her monitor actually needs, rather than assuming that a temperature value supplies a whole image. Before choosing the part, Maya tests it where the monitor will actually sit, over the temperatures it will encounter. The sensor family name alone cannot settle whether the placement or operating range fits the job. She keeps those checks tied to the room where the monitor will be used. Take away the distinction between a temperature reading and a temperature map. Choose the output that answers the question, then test the selected part in its intended position.

You can use “Read layer aloud” in the explorer for your browser’s optional voice reading.