Blackbody Temperature Reference Source

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The Covid-19 pandemic has driven the development of quick diagnostic and screening protocols to detect and sequester potentially infected individuals. Protocols may include temperature screening. Such screening might take place at businesses, schools, hospitals or airports with the goal of identifying possibly contagious individuals. This process is safer and faster when temperature monitoring can take place via non-contact means using a device called a non-contact infrared thermometer or NCIT. However, NCITs may be poorly calibrated, leading to erroneous screening outcomes. We have developed a standalone Blackbody Temperature Reference Source (BTRS) to allow easy confirmation that a given non-contact thermometer is working correctly.

The BTRS consists of a blackbody infrared emitter that is held to a precise setpoint temperature, usually near standard body temperature. The setpoint temperature is displayed on the front of the unit and is easily adjusted up and down. The BTRS has a switch to select the units of Celsius or Fahrenheit. The blackbody emitter is mounted to a thermoelectric heat pump that can heat or cool under a tight control loop. A heat sink attached to the back of the thermoelectric heat pump allows heat absorption from, or rejection to, ambient air, in order to maintain a constant temperature at the emitter. The BTRS is powered by an internal battery that can be recharged from a USB-C connection. A 0.05% tolerance RTD sensor attached to the emitter allows the determination of the emitter temperature, and that temperature is displayed on the front panel in real time.

To use the BTRS for calibration, an NCIT is simply pointed at the blackbody emitter. If the temperature reading matches the setpoint temperature of the BTRS then the thermometer is within specification and can be relied upon to monitor the temperatures of tested subjects. Otherwise, it represents an inaccurate temperature detector and the NCIT must be replaced or recalibrated.

The BTRS is factory calibrated to a traceable National Institutes of Standards (NIST) specification so that it represents a reliable, easy to use thermal reference source. Prototypes have been built, a patent is pending, and production units will ship in July of 2020.

Custom Thermolectric was founded in 2005 to manufacture thermoelectric devices. The Company grows the BiTe thermoelectric semiconductor crystals, assembles modules and integrates these modules into subassemblies and completed products. The BTRS is a natural extension and integration of Custom Thermoelectric’s product line and represents an important tool in the fight against the Covid-19 pandemic.


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  • Name:
    Andrew Masters
  • Type of entry:
  • Profession:
    Business Owner/Manager
  • Andrew is inspired by:
    Our designs are driven by perceived market needs. Starting from an expertise in thermoelectric generators and heat pumps, there are many directions for applications. We have found that successful products are more often developed in response to customer pull rather than designer push.
  • Software used for this entry:
    Fusion 360
  • Patent status: