Team:Kyoto/Hardware - 2019.igem.org

Hardware

Overview

Once we produced ideal proteins that we showed to aggregate microfibers, we considered how to apply them in a practical device. Since we learned that adding the proteins to washing wastewater at the early stage would be most efficient from the Human practice work, we designed a new device that attaches to the drain pipe of the washing machine in order to release the proteins directly into wastewater before it went down the drain. We thought the device should have two functions. First, it should release the proteins only when the wastewater is draining from the washing machine. Second, it should release an appropriate amount of proteins for the amount of wastewater.

First Trial

To make a device with the appropriate functions, we utilized the mechanism of a common laboratory aspirator. As shown in the picture below, the fluid will flow from wider to narrow side of the tube. When the fluid enters the narrow part, the velocity of the flow will increase momentarily and the fluid pressure decreases. This draws a vacuum from a hole and causes suction of material through it.

Fig.1 Aspirator (overview)

Fig.2 Aspirator (sideview)

We used 3D-printer formlab and printed this device with a clear resin. For the test run, we attached a plastic tube to four holes A, B, C and D (Fig.2 shown above). Water was flown flow from A to B, and tube from C and D was put into red-colored water. At first, we flew water with the same speed as wastewater comes out of the washing machine, however, it didn’t work well. Changing the speed of fluid faster didn’t change the result. We consider that the velocity of the flow didn’t make enough change for a fluid pressure, and since it is difficult to change the speed of wastewater itself, this device turned out to be a failure.

Fig.3 Aspirator (object)

Second Trial

Next, we look at the mechanism of sanitizer, a device that releases a certain amount of detergent, for our hardware. This doesn’t require enough speed of fluid and also works only when the wastewater is draining. When wastewater enters the container from the upper tube, the water level goes up as the water comes into the container since the upper tube is broader than the lower one. When the water level becomes high enough, the wooden ball floats and the lid opens. Therefore, our protein solution starts to flow into the container. When the effluent stops flowing and the water level goes down, the lid will close once again since the buoyancy of the ball is lost. This is how our protein solution is released automatically.

Fig.4 Mechanism of sanitizer

Fig.5 Sanitizer (overview)

Fig.6 Sanitizer (sideview)

We used 3D-printer formlab and printed this device with a clear resin. For the test run, we set red-colored water in the printed device and attached it to the container. Pouring water from the upper tube, we observed how it worked. Consequently, the open-close lid system by buoyancy worked as expected, but the adhesion of the lid wasn’t enough so colored water leaked even water was low. Also, the liquid pours all at once and couldn’t control the flow level for the amount of wastewater. Some concerns remain but we generally succeded in simulating the function of poring protein only when wastewater is draining.

Future

To improve our device, we suggest using an electronically designed device that pours protein only when it detects the flow of wastewater. We designed an electronic hardware shown below;

Fig.7 Image of electronically controlled hardware (overview)

The sensor detects the velocity of the effluents from washing machines and the microcomputer called PIC (Peripheral Interface Controller) regulates the angle of the servomotor depending on the input from the sensor. This enables it to release the protein solution according to the amount of the effluents and keep the concentration of the protein at the optimal level.

Fig.8 Design of an electronic circuit

By combining these electoronic circuits with each other, you can electronically control the release of the protein solution. The needed parts are as follows.

Waterflow Sensor (Zhiwei Robotics Corp.)
Microservo SG92R (Tower Pro Pte Ltd)
Three-terminal regulator (STMicroelectronics)
PIC Microcomputer PIC16F627A-I／P ((Microchip)/(Atmel Corporation))

Moreover, we think of using this with a filtering system and making the collecting efficiency even more for more information (see Future Application).