Portable High-Accuracy Thermal Measurement System
Precision energy delivery, temperature monitoring and low-power data acquisition
EMP Designs was approached to develop the electronics for a portable measurement device requiring extremely precise control of both energy delivery and temperature measurement.
The application relied on a small heating element being driven with a carefully controlled amount of electrical energy. Once heated, the system then needed to accurately monitor how the temperature changed over time.
The resulting temperature-decay data could then be passed to the client's proprietary algorithms, allowing them to interpret the characteristics of the material being tested.
While the principle sounds straightforward, achieving the required accuracy in a compact, battery-powered device presented several significant engineering challenges.
Precisely Controlling the Energy
The first challenge was controlling the heating element.
Rather than simply applying power for a fixed period, the device needed to deliver a very accurately controlled quantity of energy to the heater.
Small variations in current, voltage or timing could affect the starting temperature and therefore influence the subsequent measurement.
We therefore developed electronics capable of controlling the heating cycle accurately and repeatably, ensuring that each measurement began from a known and controlled energy input.
Measuring the Temperature Decay
Once the heating cycle had finished, the next stage was to monitor the temperature as it naturally decayed.
The system needed to capture this change with sufficient accuracy and at adjustable measurement intervals, producing a detailed temperature profile over time.
This data could then be processed into a format suitable for the client's own analysis software and proprietary algorithms.
Effectively, the electronics needed to perform two quite different tasks extremely well:
deliver a precisely controlled burst of energy, and then immediately become a high-accuracy measurement system.
Balancing those requirements within one compact design formed a significant part of the development work.
Designed for Long-Term Battery Operation
The device also needed to operate remotely for extended periods.
In some applications, measurements could be taken over weeks or potentially months, making power consumption an important part of the design.
It wasn't enough simply to optimise the electronics while they were active. We also needed to minimise the amount of power consumed between measurements.
Considerable development therefore went into:
reducing sleep-state power consumption
managing the system's different operating modes
optimising when individual circuits were powered
maintaining measurement accuracy while reducing energy consumption
managing data storage and communications efficiently
The objective was to allow the device to perform numerous measurement cycles over a long period without requiring frequent battery charging or replacement.
Low-Power Wireless Data Transfer
The system can store measurement data internally, but there was also a requirement to transfer collected information to a computer.
Wireless communication can be one of the largest power consumers in a battery-operated product, so we investigated ways of using newer Wi-Fi communication methods while minimising the amount of time the radio system needed to remain active.
By carefully controlling when communications were enabled, data could be transferred while keeping the overall energy consumption of the device low.
Turning an Experimental Requirement Into Portable Electronics
The result was a compact electronic platform capable of combining:
highly controlled energy delivery
accurate temperature measurement
adjustable sampling periods
long-term data logging
internal data storage
wireless transfer to a computer
low sleep-current operation
extended battery-powered deployment
The project required development across analogue measurement, precision power control, embedded firmware, power management, data acquisition and wireless communications.
It is a good example of the type of work we undertake at EMP Designs: taking a specialist measurement requirement and developing the electronics and embedded systems necessary to turn it into a practical, portable device.
Bespoke Electronic Design
If you have an application requiring unusual sensing, precision measurement, data acquisition or low-power embedded electronics, EMP Designs can develop the electronics, firmware and hardware required to turn the idea into a working system.
