Problem & Context
Accurate, localized temperature data was required from multiple points within a tightly constrained closed system where conventional wired sensors or bulky instrumentation could not be deployed. Existing system-level temperature feedback lacked the accuracy needed to understand thermal gradients and non-uniformity across critical surfaces. The BIR tool was developed to capture simultaneous readings from two thermistors and generate temperature-over-time graphs in real-time. This delivered essential thermodynamic insight that was previously unavailable.
Scope of Work
- Designed and fabricated a custom printed circuit board assembly (PCBA) to acquire temperature data from two thermistors and wirelessly transmit it to a PC.
- Integrated key components including screw terminals for thermistor connections, Seeeduino MCU, 9V battery power supply with regulation, and nRF24L01+ RF transceiver.
- Developed a companion receiver module to capture the RF-transmitted data and relay it directly to PC via USB.
- Created Python based real-time monitoring and plotting application to visualize thermistor readings alongside the system’s native temperature reference.
Technical Approach
Utilized KiCAD to design a compact and reliable PCBA with all the components required to transmit thermistor data through RF to a receiver dongle.
Implemented embedded firmware on the Seeeduino using Arduino/C++ to sample bother thermistor channels at 1Hz, convert the raw ADC values to temperature using the Steinhart-Hart equation (constants derived from multi-temperature calibration), timestamp each reading, and transmit the data packet wirelessly to the receiver.
Engineered a matching receiver dongle that received the packets and passes the data directly to the PC through USB.
Developed a Python 3.x application utilizing Matplotlib for real-time, multi-line plotting of both thermistor temperatures and the system’s reference temperature (acquired via RS485-to-USB converter from the legacy control board’s debug output)
Synchronized and overlaid all three temperature streams to enable direct comparison of local thermal behavior against system feedback.
Technical diagram or schematic would be displayed here
Results
Project results visualization
The BIR tool provided accurate temperature gradient data across critical regions of a heated surface, revealing thermal non-uniformity that was previously undetectable with single-point system feedback.
Armed with this detailed profile, the heating element was redesigned from a primarily radiant design to a convection enhanced disc configuration.
Improvements:
1. Significantly enhanced surface temperature uniformity.
2. Improved responsiveness and stability of the product’s built-in thermistor feedback control loop.
3. Reduced sensitivity to assembly tolerances and variation in system thermistor placement.
These enhancements resulted in more consistent thermal performance, better product reliability, and substantial increase in overall system quality under real operating conditions.