Week 14

Blog sheet Week 14:

This week’s blog sheet will be as group.

Your blogsheet 14 tasks:

1.       Video of your RG group setup.

Video 1: Group Rube Goldberg setup and brief explanation

2.       Video of your RG group in action

a.       Failed attempt

b.      Successful attempt

Video 2: Group Rube Goldberg Fail

Video 3: Fail again

Video 4: The ultimate fail...

We've been having minor tweaks to take care of, and every time we fixed something, another thing would go wrong. So unfortunately, we don't have a success video (so far).

Week 13

Blog sheet Week 13

This week’s blog sheet will be both individual and group.

Your blogsheet 13 tasks:

1.       Provide the updated computer drawing for your individual RG setup.

2.       Explain your setup.

3.       Provide photos of the circuit and setup.

4.       Provide at least 2 new videos of your setup in action, one being a failed attempt.

5.       What failures did you have? How did you overcome them?

6.       Group task: Explain your group RG setup.

7.       Group task: Video of a test run of your group RG.

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AJ:

1.       Provide the updated computer drawing for your individual RG setup.

Image: Computer drawing setup

2.       Explain your setup.

A solar panel will start the circuit when a cover is lifted from it from Andrew’s machine. Once the solar panel is revealed to a light source (room lighting), the voltage will transfer to an op amp and will then trigger a relay. Once the relay switches, the motor will turn on. A string will be attached to the motor and a toy car; when spinning, the toy car will charge at a balloon with a needle attached at a slight angle. The balloon will pop, starting a domino effect. I plan on adding a second motor to my circuit to help stop it after I start Vince’s machine. The idea is to pull a component out of the breadboard (i.e. one of the resistors), so that way it becomes an open circuit and stops my motors from running.

3.       Provide photos of the circuit and setup.

Image: Part of setup

4.       Provide at least 2 new videos of your setup in action, one being a failed attempt.

Video: Relay was going crazy when I used a new motor (3V) 

Video: Plan B motor

Video: Mini test run (sorta failed)

I was able to obtain a smaller motor as shown in last week, however my motor went missing. So over the weekend I decided to go buy two motors, that way I have my own. However, when I tried connecting either of them to my original layout, the relay went crazy. I'm going to be figuring out this problem this week.

5.       What failures did you have? How did you overcome them?

My current issue is having my new motor spin. Not sure why, but the relay was just buzzing and my motor didn't spin at all. I've adjusted the voltage input, but was either getting nothing or the same buzzing sound. I haven't figured out a way to solve this yet due to lack of time. I'll be looking over it this week.

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Andrew:

1.       Provide the updated computer drawing for your individual RG setup.

Image: Andrew's computer pic

2.       Explain your setup.

Initially the solar panel will be covered that way the circuit will not be functioning. Once the solar panel becomes uncovered it will transform the light into a small voltage, which will be amplified by the OpAmp enough to trigger the relay to switch. Once the relay switches, the +5VDC will be applied to the motor, which will turn it on and raise the flag (and hopefully trigger the next circuit to activate.) Once the flag has been raised to the top the motor will lift an object (a chunk of cement) off the limit switch that will turn off the motor. Also, the +5VDC applied to the motor might need to be calibrated (changed) slightly. It will probably be more like +3VDC this way the motor doesn’t run too fast and mess something up. We want a slow and controlled motion. 

3.       Provide photos of the circuit and setup.

Image: Circuit set up

Image: Whole set up

4.       Provide at least 2 new videos of your setup in action, one being a failed attempt.

Video: Test Run 

Video: Test run 2

5.       What failures did you have? How did you overcome them?

The one thing that had to be adjusted was the voltage being applied to the motor, at first it was too low and the motor wouldn’t even spin. This is a simple problem to fix, you just have to increase the voltage slowly until you get to a voltage that comfortably starts and keeps the motor spinning. Other then that, I didn’t have too many problems

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Vincent

1.       Provide the updated computer drawing for your individual RG setup.

2.       Explain your setup.

The setup is pretty much the same with only a few changes

The first change I made was the addition of a solar panel to power the circuit instead of a force sensor. This change occurred after I was still having trouble providing enough power to the relay. Instead of providing power the force sensor was shorting the entire circuit. The second change I made was changing my mechanics a little bit I added a plastic cup attached to a string at the end of the ramp setup. The string is attached on two different ends when the ball falls in the cup it will do two things at once. On one end the sudden drop will pull the cover that is placed over the solar panel starting the next machine. The other end of the string will be attached to a small cardboard piece that when pulled will block the light source on my solar panel turning off my motor.

3.       Provide photos of the circuit and setup.

Image: Motor/cardboard trigger

Image: Solar panel as new power source

Image; Full setup

4.       Provide at least 2 new videos of your setup in action, one being a failed attempt.

Video: Success run

Video: Failed run

5.       What failures did you have? How did you overcome them?

the big failure I had was getting the force sensor to power my circuit. After several different setups and getting the same result of shorting my circuit I decided to change to a solar panel as my power source. This new power source worked perfectly and provided the power I needed.

The second issue I faced was how to turn off my circuit when complete I also tried to incorporate my force sensor but again ran in to the issue of shorting out my circuit to early. I solved this issue by changing my mechanics and rigging a cup to a string that will pull down a small cardboard piece over my light source turning off my circuit. 

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Group:

1.       Group task: Explain your group RG setup.

Starting with Andrews:

A solar panel will become uncovered and the signal amplified by an opamp, which will then trigger a relay to switch. Once the relay switches, power will be delivered to a motor which will raise the flag. Then, as the flag reaches the top, the motor will do two things. First, it will lift a small piece of cement off a switch which will cause the motor to stop. Secondly, it will remove the covering on AJ's solar panel and trigger her circuit. This signal will be amplified as well by an opamp which will trigger a relay delivering power to a motor. The motor will spin pulling a car across and end up popping a balloon, which will then cause a chain reaction of dominos to fall and  eventually uncover the light source that will activate Vince's circuit. The light source will be absorbed by another solar panel which will, again, be amplified by an opamp and trigger a relay. This will then provide power to a motor pulling a stopper releasing a ball. The ball will then roll down a ramp and into a cup, which will then fall of the table, pulling a piece of paper off the next solar panel and it will then trigger the next circuit.

2.       Group task: Video of a test run of your group RG.

Video: Test run of group RG (failed)

We have a lot of tweaking to do for our group RG. We're currently working on fixing our own RG and making sure ours starts the next RG. 

Week 12

Blogsheet Week 12:

This week’s blog sheet will be individual but you will post it on your group blog.

Your individual Rube Goldberg (RG) setup should satisfy the following:

1.       Use at least 2 of the following components:

a.       Transistor

b.      OPAMP

c.       Relay

d.      Temperature sensor

e.      Photosensor

f.        Motor

g.       Display

h.      Strain gauge

i.         Speaker

j.        Microphone

k.       Solar panel

2.       Use a new circuit: It can be a modification to one of our lab circuits.

3.       Let your system complete its task in no shorter than 10 seconds.

4.       Make sure you are compatible with your preceding and following RG stage.

Vince:

1.       Provide the computer drawing for your individual RG setup.

2.       Explain your setup.

The whole device is triggered by an object landing on the force sensor. The input voltage goes through the oamp and is multiplied by a non-inverting amplifier. This new input voltage is sent to the relay. On one end is a led that is already on on the other is a motor turned off. When the relay is triggered the motor turns on. This begins winding a string attached to a small cardboard flap that is keeping the ball on top of the ramp. The flap is removed and the ball rolls down the ramp triggering the next device.

3.       Provide photos of the circuit and setup.

Image 1: Starting setup with force sensor as trigger

Image 2: Add LED to one end of relay

Image 3: Full set up

Image 4: Test one of entire set up

4.       Provide at least 2 videos of your setup in action, one being a failed attempt.

5.       What failures did you have? How did you overcome them? 

One of the major issues I have had is being able to use the force sensor to trigger the relay. The problem is getting the input voltage high enough to trigger the relay. I am trying different resistor combinations in a non-inverting amplifier set up.

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AJ: 

1.      Provide the computer drawing for your individual RG setup.

Image 1: Schematic idea #1

Image 2: Schematic idea #2

Image 3: Physical Rube Goldberg setup

2.      Explain your setup.

Idea #1: A solar panel will start the circuit when it is revealed to a light source from Andrew's machine. The capacitor will build up and the capacitor voltage will start the dc motor. With Idea #2, the voltage from the solar panel will transfer to an op amp, which will help trigger the relay. When the relay switches, it will turn on the 6V dc motor. The motor will begin to spin, pulling a car that is attached to a wire. On the front car, there is a needle. The car will drive into a balloon, popping it with the needle, and hope that there will be enough force from the balloon pop to start a domino effect (the balloon and the first domino will be touching each other). At the end, the last domino will fall onto the force sensor of the next Rube Goldberg machine.

Update: Decided to go with Idea #2

3.      Provide photos of the circuit and setup.

Image: Breadboard layout of Idea #2

Image: Breadboard with solar panel of Idea #2

4.      Provide at least 2 videos of your setup in action, one being a failed attempt.

Video 1: AJ's failed test run

F

Video 2: AJ's successful test run

5.      What failures did you have? How did you overcome them?

I was having issues starting up my motor; since it's a bigger motor, I need to supply enough voltage to make it spin. I might have to add in an opamp (non-inverting). I wanted to use a photosensor to start the circuit, but had to use a solar panel instead. Before I connected the motor at the end, I was measuring about 6.5 V, which is enough to make the motor spin. But when I connected the motor, the voltage significantly drops to around 35 mV. It's becoming a reoccurring issue; probably something simple to fix though. 


Update: I was able to make a smaller motor run compared to the larger motor. I switched the large motor out for the small one since Andrew wasn't using his anymore for his machine (as of today at least). I fixed the values of the resistors to have a higher gain to trigger the relay and move the motor. However, now I need to make the physical part of my machine and test it out this week. 

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Andrew:

1.      Provide the computer drawing for your individual RG setup.

2.      Explain your setup.

Initially the solar panel will be covered that way the circuit will not be functioning. Once the solar panel becomes uncovered it will transform the light into a small voltage, which will be amplified by the OpAmp enough to trigger the relay to switch. Once the relay switches, the +5VDC will be applied to the motor which will turn it on and raise the flag (and hopefully trigger the next circuit to activate.) The only change that might be made is to install a current limiting resister between the motor and relay.

3.      Provide photos of the circuit and setup.

Image: Andrew's breadboard layout

Image: Andrew's nifty wheel :)

4.      Provide at least 2 videos of your setup in action, one being a failed attempt.

Video 3: Andrew's failed Test Run

Video 4: Andrew's Success Test Run

5.      What failures did you have? How did you overcome them?

I needed to play around with the resistor values to get a high enough gain to move the crane setup. I also switched out my motor because the crane will be more efficient to pull the string and raise the flag.

Week 11

Blog sheet Week 11: Strain Gauges

Part A: Strain Gauges:

Strain gauges are used to measure the strain or stress levels on the materials. Alternatively, pressure on the strain gauge causes a generated voltage and it can be used as an energy harvester. You will be given either the flapping or tapping type gauge. When you test the circle buzzer type gauge, you will lay it flat on the table and tap on it. If it is the long rectangle one, you will flap the piece to generate voltage.

1.       Connect the oscilloscope probes to the strain gauge. Record the peak voltage values (positive and negative) by flipping/tapping the gauge with low and high pressure. Make sure to set the oscilloscope horizontal and vertical scales appropriately so you can read the values. DO NOT USE the measure tool of the oscilloscope. Adjust your oscilloscope so you can read the values from the screen. Fill out Table 1 and provide photos of the oscilloscope.

Table 1: Strain gauge characteristics

Flipping strength	Minimum Voltage	Maximum Voltage
Low	-3 V	3 V
High	-10 V	10 V

2.       Press the “Single” button below the Autoscale button on the oscilloscope. This mode will allow you to capture a single change at the output. Adjust your time and amplitude scales so you have the best resolution for your signal when you flip/tap your strain gauge. Provide a photo of the oscilloscope graph.

Image 1: Single change output

Part B: Half-Wave Rectifiers

1.       Construct the following half-wave rectifier. Measure the input and the output using the oscilloscope and provide a snapshot of the outputs.

The input is 10Vpp at 1kHz

Output is 4.56Vpp

Image 2: Half wave rectifier output

2.       Calculate the effective voltage of the input and output and compare the values with the measured ones by completing the following table. 

                       Table 2: Effective (rms) of input and output voltage                         

Effective (rms) values	Calculated	Measured
Input	3.53 V	3.54 V
Output	1.61 V	1.58 V

Equation used for calculated values: Vrms = (Vpp/2) (.707)

3.       Construct the following circuit and record the output voltage using both DMM and the oscilloscope.

Table 3:  Output voltage readings with 1 µF

	Oscilloscope	DMM
Output Voltage (p-p)	2.32 V	Not possible
Output Voltage (mean)	2.89 V (not possible..?)	Not possible

The mean shouldn’t be higher than the peak to peak value. It should be somewhere between the peak to peak voltage. It's also impossible to measure the peak to peak value and mean value on the DMM.

4.       Replace the 1 µF capacitor with 100 µF and repeat the previous step. What has changed?

Table 4: Output voltage readings with 100 µF

	Oscilloscope	DMM
Output Voltage (p-p)	160 mV	Not possible
Output Voltage (mean)	3.28 V	Not possible

What changed after replacing the capacitors is that the output voltage peak to peak was smaller than the mean output voltage.

Part C: Energy Harvesters

1.       Construct the half-wave rectifier circuit without the resistor but with the 1 µF capacitor. Instead of the function generator, use the strain gauge. Discharge the capacitor every time you start a new measurement. Flip/tap your strain gauge and observe the output voltage. Fill out the table below:

Table 5: Output voltages at different tap frequencies

Tap frequency	Duration	Output voltage
1 flip/second	10 seconds	1.15 V
1 flip/second	20 seconds	1.16 V
1 flip /second	30 seconds	1.27 V
4 flips/second	10 seconds	2.14 V
4 flips/second	20 seconds	2.2 V
4 flips/second	30 seconds	2.3 V

2.       Briefly explain your results.

According to our chart,the more taps you do, the higher the output voltage. When you do a steady tap, the voltage generally stays the same. When you do multiple taps per second, it slowly increases.

3.       If we do not use the diode in the circuit (i.e. using only strain gauge to charge the capacitor), what would you observe at the output? Why?

When we didn’t use the diode, the output wasn't consistent. When you use a diode, it only allows positive current to flow; without it the capacitor wouldn't really charge.