Week 8

Rube Goldberg Take 2

Draw and explain a Rube Goldberg design that will include the following components:

•         Digital
•         Motor
•        Relay
•        Opamp
•     Temperature sensor
•     LED

The setup should be considered to last 30 seconds.

Make sure to include enough photos, videos, and explanations for each “transition” or step. Explain your circuits. Put at least 2 issues/problems/struggles you faced during the project.

For our Rube Goldberg, we decided on having a ball travel downwards on a ramp until it hits the force sensor, thus activating the digital display and LED lights (one green and the other white). The ball will start at the top, its path blocked by a small door. When we apply heat to the temperature sensor, the DC motor will start to spin, thus opening the door so the ball can continue its path. At the end of the path, the ball will then drop onto a platform where the force sensor is located in. The weight of the ball will activate enough force for the digital display to count from 0 to 9 at 1 second per count. From there, depending on what number is displayed, either the green or white light will turn on. The LED lights depend on what number is being displayed. We used an OR gate to implement this idea. 

Step 1: Circuit Design

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Image 1: Very basic schematic design of our project

Image 3: Final breadboard layout ft force sensor platform

Image 2: Sketch 2 of mechanical idea

 

 Image 4: Figuring out a way to have both LED lights turn on and off respectively

Image 5: Building plan B of ramp

Image 6: Force Sensor inside platform

Step 2: Operation of Circuit

Start: We will place our marble/ball at the top of the ramp, which the path will be blocked by our door.

Step 2a: Activating the DC Motor

We apply heat to the temperature sensor using a hair dryer. By doing this, the voltage of the temperature sensor will increase, thus activating the DC motor. The DC motor will then spin. We attached a simple string to the motor and the door. When the motor spins, it will pull the door out of the ramp, allowing the marble/ball to continue its path

Video 1: Basic DC Motor Test

Video 2: Test Run 1

Step 2b: Activating the Force Sensor

At the end of the ramp, there's a hole allowing the marble/ball to drop into. Once it falls, the marble/ball will land on top of the force sensor. To make sure the ball doesn't roll off, we built a small platform to put the force sensor into, allowing the ball to stay on top of it. The weight of the ball will activate the force sensor

Video 3: Force Sensor test

Step 2c: Activating the Digital Display

Our digital display will turn on when the ball is on top of the force sensor.

Video 4: Test Run 2

Video 5: Test Run 3

Step 2d: Activating the LED Lights

Once our digital display is on, the display will count from 0 to 9. Depending on which number it's on,either the green or white light will turn on. In this design, the green light will turn on first, starting from 0 to 4, and then the white light will turn on from 5 to 9.

Video 6: Rube Goldberg explanation

Issues and how we overcame them:

•          We want each light to flash on and off like a blinker. However, one light would stay on while the other light stays on.
• Fixed our connections
• Added another opamp 
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•        We also had issues trying to get the motor to spin when applying heat to the temperature sensor
• We had to add another relay 

•         For our ramp, we decided to not do a loop for the ramp. We would’ve had to manipulate the cardboard and use smaller sections in order to create a decent curvature for the loops, thus possibly taking up more time than needed
• We decided to implement ramps, but instead have them stagger downwards
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• The original idea of the door was a minor problem due to the design of the ramp and where the door sits in. Also, when the DC motor spins, the tension from pulling the door was also slowly weighing down our ramp, causing the ball to not roll forward once the door was opened. 
• We ended up creating a different way to implement the door idea. 
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Video 7: Our Rube Goldberg...almost

Video 8: Presenting our Rube Goldberg, which failed

Conclusion:

Unfortunately, our Rube Goldberg didn't work halfway through. We ran into some last minute issues before presenting, such as our force sensor not working anymore and the relay for the digital display not allowing the LED light to switch over when the counter is on 4. We noticed that when we don't apply the temperature sensor in the circuit and just by applying power to the motor, the circuit works just fine; the ball lands on the force sensor and the digital display is activated, causing the lights to turn on. However, when we do apply the temperature sensor, it seems like we're drawing in too much current somewhere. In one of the videos above, you can see where the lights and digital display are sporadically turning on and off and hearing a rapid clicking sound from the relays. We also were thinking that we may have fried out a part somewhere on our board from constantly applying heat. For example, our force sensor wasn't working at the end. Originally we thought that the platform for the sensor was sitting too low, possibly allowing the leads of the sensor to pop out of the breadboard just enough to not allow it to work. However, we adjusted the platform and was still getting the same outcome. If we were to do this again, we would've gone about doing our Rube Goldberg differently; maybe implement the temp sensor in a different way or create a completely different idea.

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