Our "Power Up Your Bench Contest" Week #6 winner is Jon Snowman.
Here is Jon's story:
I’m an engineer who was inspired at high school to learn electronics, and I have continued it as a hobby ever since. I am therefore immensely passionate about helping schoolchildren become as engaged and excited about science, technology, engineering and maths (STEM) subjects as I am, and to encourage them to take them up at university and in their future careers.
Engaging schoolchildren with STEM subjects is considered difficult, since they can appear too academic with too few practical elements and demonstrations. To address this, I began designing and building VertigoIMU - a compact inertial and GPS datalogger which gives physics students previously impossible insight into physical systems. From the ground up, I have captured the schematic, designed the PCB and fabricated prototypes to be tested by the school.
VertigoIMU comprises a 9 degree of freedom IMU (3 axes of each of acceleration, gyroscope and compass), a high precision 10Hz GPS unit, barometric pressure, humidity and temperature. Data is logged to a microSD card for analysis.
Some examples of where we have successfully deployed VertigoIMU:
• On a rotating bicycle wheel to demonstrate the equations of circular motion such as centripetal acceleration (a = w^2 x r).
• On the GreenPower competition vehicle – an electric vehicle built by the students – to examine the lateral forces on the wheels to inform decisions about tyres. A plot of acceleration whilst being driven in a circle is shown below.
VertigoIMU prototypes are being tested at the school with great success. However, the principal complaint is that battery life is not long enough. Since the GPS must maintain a lock before datalogging commences, and between datalogging runs, an optimised ‘standby’ mode is required, in which the GPS retains lock and all sensors are initialised and ready.
Longer battery life is essential so that students can capture exciting data with VertigoIMU, especially applications in which the unit must be powered up and achieve GPS lock for a long period before datalogging commences. Some examples include:
• Roller coasters – the students are planning a visit to a local theme park
• Flight analysis – capturing the angle of attack of a BASE jumper
How the E36312A would help
This power optimisation would benefit hugely from an E36312A power supply, as I am currently using lithium polymer batteries only. The main reasons are:
1. High precision (<20mA) current readback mode. This would allow me to quantify and optimise the standby power consumption. This is not possible with standard bench power supplies as they typically have current precisions of around 10mA.
2. Overvoltage protection (OVP) and overcurrent protection (OCP). Short circuiting or over-charging/discharging of lithium batteries can be dangerous. The safe OCP/OVP modes of the E36312A would enable safer working in my home lab.
3. Programmable. This would permit me to simulate the discharge curve of a battery to understand details such as the total run time of the device and calibrate the battery gauge.
4. Multiple channels. This would accelerate develop