This temperature sensor measures temperature with an absolute accuracy of 0.1℃. It is based on the TSYS01 sensor chip from TE connectivity. The accuracy of the chip is quaranteed by the manufacturer and includes aging and self-heating. No further calibration is required.
The chip is ready to use. However, when placed near other chips, these chips may unintentionally warm-up the sensor.
Therefore, a special electronics & PCB-design has been made that reduces the warming-up of the other chips used and minimizes the heat-flow and/or radiation from these chips to the sensor.The design includes a microcontroller chip and a USB-interface chip (see schematics design). Nearest to the sensor chip is the microcontroller. To minimize the heat produced by the microcontroller, it was essential to put the microcontroller in a "sleep" mode most of the time. Only when a sample was taken (1 sample/sec), the microcontroller was taken out of the sleep mode. The USB-interface chip is furthest away from the sensor (see PCB-design), but produced the most heat (a few ℃ hotter then the environment). To reduce this, a copper plane was put directly under the chip and was connected to the metal part of the USB-connector to cool away part of the heat produced by the chip.
The first design did not have these measures and the heating of the sensor due to the other chips was obvious (almost 0.5℃ heating after approx. 15 minutes. The final design only has approx. 0.03℃ total self heating after 5 min which is way below the sepcified 0.1℃ accuracy.
For some results, see figures below. The left figure shows recording results of the initialy designed sensor. The figure on the right shows the recording results of the final design. Both recordings were made at the same time in a closed temperature cabinet. The recordings were started immediately after powering-on the sensors. During the approx 15 minute recording, the temperature in the cabinet very slightly increased due to a outside temperature rise. The figure on the left shows an additional temperature rise due to the heating-up of the sensor caused by the other chips.
A dedicated software tool has been made to control and read-out the sensor.
