Challenge:
Team of 5: develop a device that will quantify the iron levels of a patient’s bone marrow in real time at the point of care by incorporating research-phase body iron detection technology into a non-invasive, handheld "Iron Wand" designed for clinical pediatric use.
Skills:
SolidWorks, Thermal Analysis, Thermal Management, 3 Axis Machining, 3D Printing, Human Factors, Client-Consultant Interaction
Individual Contribution:
Human Factors Lead, Coil-housing Machining, Cooling System Exploration, SolidWorks and 3D Print Lead.
We began with our client, Lodestone Biomedical, and their bench top technology for detecting body iron using electromagnets. Our job was to turn their invention into a handheld pediatric product. The device was to be used by doctors and nurses on an infant's sternum when it is lying on its back.
My first task was to explore general form factor options from a variety of industries and prototype a few of the most promising ones.
hand-carved foam explorations of handle design
state-of-the-art research into handheld devices
hand-carved wooden refined designs
initial concept drawings
Though our search was extensive, we spoke with a number of doctors and landed back close to home with the otoscope model as the most comfortable and easy-to-use device shape for our particular application.
We planned for the electromagnets to be housed within a set of heat sinks to manage their operating temperature, as our calculations pointed towards passive cooling as being adequate for our power draw. The designs are shown below.
heat sinks
pickup coils
drive coils
Two driving coils provide current and a magnetic field. Two pickup coils measure the induced magnetic field produced by the iron atoms in the user's body.
An initial SolidWorks model of a full body design.
As we learned more about the science behind the magnetic imaging, our calculations changed and we realized that a passive system with heat heat fins would not be sufficient to keep the coils within their operating temperature. We moved to exploring options for active cooling.
iterations for custom fan blade
The magnetic field generation coils could not have other electronics in their vicinity, so we had to come up with ways to actively cool the device without close electronics. We eliminated liquid cooling due to its high complexity, and explored various options for forced-air cooling. My first set of iterations focused on a rear-powered plastic fan design.
the DC motor was housed sufficiently far from the coil chamber to not magnetically interfere with the measurements
After testing all of the iterations, it was clear that even the best fan did not provide enough airflow. We pivoted to an air pump strategy, testing various flow rates and orientations of flow to find the most effective design.
Our final design utilized an external air pump and a standby mode to quickly reach operating temperature during use. In standby mode, the coils preheat. When a doctor wants to use the device, they flip the device into operational mode, whereby the fans turn on and bring the device to operating temperature much more quickly than if the device was turned on cold.
final SolidWorks model