Prototyping

Aluminum pipes

Yiao Xiang finally agreed to let us drill holes on our aluminum pipes. Yay!

Our blogger turned engineer

Drilled pipes!

Load sensor

Our load sensor was delivered, so we began figuring out how to operate it. We learned that both ends of the sensor need to be mounted to separate surfaces, with a spacer used to isolate the sensor from direct contact.

Credits: Randomnerdtutorials.com

So, we decided to model and 3D print both a platform and a spacer for the top and bottom of the load sensor. The top platform includes a groove designed to securely hold our aluminum poles.

We also soldered the wires of the load sensor to the HX711.

Our group leader, hard at work

We set up a rough prototype for the load sensor and tested our code to check its functionality. Using items of different weights—a servo motor, power bank, and a bag of screws—we estimated the calibration factor to convert the sensor’s voltage output into mass.

Results:

We conducted experiments to test if our platform could support the weight of the aluminum poles and wet clothes. By applying force until the platform broke, we used the load sensor to measure the corresponding weight that caused the failure.

Our 3D prints successfully held up to 4.3 kg of weight — strong enough to support the load of wet clothes and aluminum poles!

Heating element

We had ordered a silicon heating strip that heats up to 50°C and maintains that temperature. Our plan was to insert the strip into the aluminum rod, allowing the air to heat up as it flows through the pipe alongside the strip.

However, during testing, we realized that the heating strip required a high current at 12V, which wasn’t feasible with our setup. Additionally, when placed inside the rods, the fast airflow from the centrifugal fan didn’t allow sufficient heat exchange, and the strip took a long time to heat up as it was operating below its optimal voltage.