Week 5 - Journal

Design the circuit using Tinker Cad

Wiring the circuit

Power Supply (5V)

• Positive terminal (red) → goes to one pin of the slide switch.

• Negative terminal (black) → goes directly to the motor’s negative terminal and the LED’s negative side (through the resistor) which limits the current flowing through the LED, preventing it from receiving too much current and burning out while the motor operates.

Slide Switch

• One pin connected to the positive terminal of the power supply.

• The other pin connected to both:

  • The positive terminal of the LED (through its current-limiting resistor).

  • The positive terminal of the motor.

LED with Resistor

• Anode (positive) → connected to the switch output.

• Cathode (negative) → connected to the power supply’s negative terminal.

Motor

• Positive terminal → connected to the switch output.

• Negative terminal → connected to the power supply’s negative terminal.

Simulation Video of the circuit

Preparing the cardboard

I spread the cardboard sheet on the table, and started to imagine the right dimensions that would fit my components inside.my target was to make as minimum jumper wires and make the device compact and neat. My target dimensions were 10 by 12 centimeters.

Instead of making each side separately, I decided to craft the three sides from a single piece, a continuous strip of cardboard to avoid  sharp, boxy corners. So, I measured 12 centimeters for the height, 10 for the width — a total length of 30 centimeters. All neatly marked in faint pencil lines.

With the cutter in my hand, I pressed gently along the fold lines—not to slice all the way through, but just enough to cut the surface. This little trick would let the cardboard bend at the sides.

The outer edges came next. Guided by my ruler for the straight cuts, leaving behind clean, sharp edges.

Instead of making each side separately, I decided to craft the three sides from a single piece, a continuous strip of cardboard to avoid  sharp, boxy corners. So, I measured 12 centimeters for the height, 10 for the width — a total length of 30 centimeters. All neatly marked in faint pencil lines.

With the cutter in my hand, I pressed gently along the fold lines—not to slice all the way through, but just enough to cut the surface. This little trick would let the cardboard bend at the sides.

The outer edges came next. Guided by my ruler for the straight cuts, leaving behind clean, sharp edges.

I faced a small problem: I didn’t have a compass around to draw the perfect circle for the washing machine’s door. So I improvised. I painted the rim of the can’s opening, pressed it gently against the front panel, and left behind a painted ring—a perfect guide for cutting the opening. 

I also cut small openings for the LED and the power switch, making sure they would be both functional and easy to access. And finally, to give the whole machine a polished, metallic look, I coated it evenly with a layer of silver spray paint—watching the cardboard transform into something that looked more industrial! 

Wiring the circuit

I wired the LED and tested it using the switch making sure that everything is working before putting them in place .

From the very beginning, I had also set myself a small challenge: to use as little glue as possible. I wanted the device to feel neat, precise, and easy to disassemble if needed. For the motors, I designed two narrow tabs that fit securely between the sides of the body. With careful alignment, the motor slid into place, held firmly by the structure itself.

I also wanted to create a small compartment for the wires and electronics, keeping them safely separated from the motor’s moving parts. To do this, I used another large tab, cut to size so it would fit securely between the sides of the body, forming a neat divider that kept everything organized and protected.

The final product!

Introducing the washing machine!

The washing machine in action!

I wanted to minimize the use of crocodile clips in the circuit and avoid unnecessary extra wires. The challenge was how to connect the LED with the resistor with no soldering or crocodile clips. So, as shown in the images, I removed the metal terminal from the female jumper housing, inserted my wire directly into it, and then slid it back into the plastic casing. This way, I could make neat, direct connections without bulky clips, keeping the wiring cleaner and more secure.

I challenged myself this week to use minimal glue and reduce the number of wires, aiming for a compact design that could be easily disassembled for future optimization. This approach mirrors the exact challenge I expect to face in my final project, making this week an excellent hands-on practice for applying those good practices.

This week, the coolest thing I learned was about washing machine door hinges. I had designed my washing machine with a right-side hinge because it suited my workflow better. But I noticed that real washing machines almost always have the hinge on the left. That curiosity led me to discover that this isn’t random — there’s a long history and practical reasoning behind it.

Most manufacturers place the hinge on the left so the door swings open to the left, leaving the right hand free for loading and unloading (especially convenient for the 90% of people who are right-handed). It also makes it easier to transfer clothes to a dryer typically placed on the right, avoids blocking detergent drawers, and keeps plumbing and electrical layouts efficient. I was surprised how a small design choice like hinge placement is influenced by decades of standardization, ergonomics, and manufacturing efficiency.

I also learned that washing machine doors are irreversible—they’re fixed to one side from the factory, and swapping the hinge would require a major redesign, new parts, and changes to the locking mechanism, wiring, and door seal. This is completely different from most dryers, which have reversible doors that let you easily switch the hinge side to match your space.