"The way to succeed is to double your failure rate"
- Thomas J. Watson, pioneer in the development computing equipment for IBM
The design process is iterative, which means that steps are repetet as many times as necessary. Making improvements along the way and to learn from failure and uncover new design possibilities.
Disclaimer: Engineering cycle2
On this site the engineering process is described only for our hardware. To see the engineering process for our model please have a look at our model site.
First run of the engineering cycle
The purpose of the box was to create a dark space for fluorescence detection into which a microtiter plate containing the sample/the samples and the lysates of our detection system can be inserted by means of a drawer. Through an opening on the top of the box, photos can be taken with a cell phone with a flash light function. Due to the filters in front of the flash as well as the camera, certain wavelengths can be detected. The cell phone attachment is interchangeable and thus the box can be used with different cell phones. After the initial design of the box was created, the first prototype was 3D printed. When the first version was tested, we encountered several problems: First, because of the camera position on the cell phone, the drawer had to be redesigned to get a photo that shows the necessary area. Secondly, we have established that the drawer is too small for the microtiter plate we have planned to use.
Second run of the engineering cycle
In the second version, attention was paid to the usage of less material as well as fixing all the flaws we identified in the first engineering cycle. This allows resource-saving production of the box, as well as a less expensive and lightweight design. The second version was printed and then tested by a physician. He recommends a reduction in the steps required to use the box to facilitate the application in a medical practice and make it easier to understand for everyone.
Picture above shows the second version of the box.
An insight into the successful application is provided here: proof-of-concept
Third run of the engineering cycle
Through the feedback from a medical professional, the second version of the box was redesigned. To implement the tips of the professional, it had to be modified so that fewer steps are needed to detect antigens. Therefore, the third version of the box takes over the individual pipetting steps by pumping the lysates into a Petri dish inside the box, when pushing a button. This makes the use of the box more understandable for everyone and enables a quick operation by physicians.
Therefore, the third version of the box was designed to allow access to the inside of the box. Since we are dealing with three different lysates and therefore three different pumps with tubes, an adapter was printed that connects the three tubes to one passage that leads to the Petri dish inside the box. The electrical system is stored separately outside the box to maintain physical separation between the sensitive electrical elements and the microtiterplate. A circuit diagram was created and the pumps were programmed. The final version of the box was then 3D printed and the pumps installed. After 3D printing, the box got successfully tested.
A video of the pump function can be seen here: Hardware
Picture above shows the third version of the box. On the left you can see the adapter, which connects the three tubes in a passage with the inside of the box. You can also see the interchangeable cell phone holder. For the drawer, a holder for the petri dish was printed to keep it in place.
Picture above shows the third version of the box with the connected tubes and pumps