Friday, March 3, 2017



Blogsheet week 8
Rube Goldberg Take 2



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


Figure 1.1 Basic drawing of Rube Goldberg circuit

Video 1.1 Explanation of individual components of Rube Goldberg circuit

The circuit starts with the temperature sensor receiving heat to output about 1 volt. This 1 volt went to the input of the OPAMP with a gain of about 7. This 7 volts would power the relay's magnetic coil switching to provide power to pin 4. The relay would provide power to the 555 timer so it will start providing a signal to the BCD. The BCD will count on this signal from 0 to 9. The display driver is connected to the BCD to receive A,B,C and D to come up with a 4 bit binary number. The display driver is connected to the 7 segment display to show what number the BCD is on. There is an AND gate connected to BCD's A and D outputs. When A and D are on (1001 in binary or 9 in decimal), the AND gate will output 5 volts directly to the motor, spinning the shaft and knocking the wheel down the track to hit a string of dominoes to transfer over to the next Rube Goldberg from another group. 



Video 1.2 Trial run of Rube Goldberg circuit from start to finish






        Digital (7 segment display):

Figure 1.2 Photo of connections on 7 segment display

Note that our display is showing zero right now, one of the segments are burnt out. We verified by directly connecting the suspect segment and still had no luck in lighting it up.

         Motor:

Figure 1.3 Motor attached to table awaiting "9" on the BCD counter to operate

        Relay:

Figure 1.4 Relay connections with LED signifying the relay has switched
        Opamp:

Figure 1.5 OPAMP with a gain of about 7, connections provide voltage for relay coil to switch
        Temperature sensor:

Figure 1.6 Temperature sensor connections, provides input for OPAMP
        LED:

Figure 1.7 LED turns on when relay switches to signify the 555 timer is operating

      555-Timer:

Figure 1.8 555 timer connections, provides a signal to BCD counter to begin counting

   AND gate:

Figure 1.9 AND gate connections, when BCD counter's A and D outputs are on (9 in binary) AND gate outputs 5 volts to the motor directly
    74192 (BCD): 

Figure 1.10 BCD connections, receives timer signal and counts from 0 to 9, sending that to the 7447 driver
    7447 (display driver): 

Figure 1.11 Display driver connections, connected to each corresponding segment with resistors, provides ground for corresponding segment from 74192 signal

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.

Problems/Issues with our Rube Goldberg circuit:

1.) We did not have a reliable way of resetting our BCD to 0 get the Rube Goldberg "prepped for show". So we would manually connect the 555 timer until it reached 0 and then use the original set up to run the Rube Goldberg circuit.

2.) Another large problem we had was the OPAMP we originally chose to use was the 741 which was unable to provide enough current for the relays magnetic coil. The circuit would only work intermittently which took a lot of time to diagnose the problem. So we had to switch the 741 for the 324 OPAMP which was able to provide enough current for the relay's magnetic coil.

3.) Generally a problem we had continuously was we had wires from capacitors and resistors touching each other unintentionally effectively "shorting" that part of the circuit. So we did struggle with setting up our connections in a clean matter to reduce these short circuits.






17 comments:

  1. I found the use of the LED and the 7 segment display in your circuit interesting because they seemed to be used more or less to show that other parts of the circuit were working. If my group had done this, maybe our trouble shooting would have not taken as much time.

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    1. Thank you, we tried to be creative as much as see could.

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  2. I really liked how you guys used your timer and led in the set up, it made it easier to anticipate what was happening next in the circuit instead of it just waiting a certain amount of time, then making the motor spin to knock the ball down the ramp.

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    1. Yea this was the idea. We are glad that you liked it.

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  3. One thing I really liked on your set up was the amount of time that it took for the circuit to finish. It really allowed for you to see what the circuit was doing. I also thought your little bridge set up was really cool and unique. Good job guys!

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    1. We had to add some resistor in order to get it that long.
      Thank you.

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  4. i thin your project is very interesting and the use of the and gate to make the motor works when the seven sigma display reaches to #9 and make the tires hit the domino, i think it is amazing

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    1. Thanks, but using AND gate did not provide enough current to the motor. So I don't recommend using it.

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  5. You're set up seemed to run pretty flawlessly! We had the exact same problem with the op amp current not being great enough to cause the relay to switch. Your video explanation was very clear and precise. Finally, your final goal was accomplished smoothly! Great job! Did you guys have the foresight to place the temperature sensor away from your other components or was that a little trial and error experience?

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    1. We lost a lot of time trying to make the relay switch. We put the temperature sensor because when it was closer we melt some stuff by the hair dryer.

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  6. Your setup seemed very similar to another groups that I had viewed, but seemed to work out much better. I am very impressed with how well your circuit ran. How do you get the timer to have such a long delay between steps? I would also like you add that your explanation video went into very deep detail and made it easy to understand what the goal was. Overall, great job this week. I look forward to seeing what you come up with for the final Rube Goldberg circuit.

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    1. We played a bit with the resistors in order to get it work that long.

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  7. Nice job with your RG, your group's is the first one I've seen work properly through video, and you explained the process extremely well. Very complex circuit layout, am impressed that you got your timer/counter to work correctly. The pictures of the steps seem to be helpful, will definitely be using this post as a future reference for setting the timer.

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  8. I liked the way you explained your circuit set-up in your video. I think this is my favorite Rube Goldberg I've seen so far. I like that you put a lot of thought into the ramp and the ball rolling down to hit the domino's in place. The resistors touching is also a problem that came up in previous weeks for me and my group. It's hard cause if you don't know to look for that problem then you'll think your circuit is wrong and struggle finding the problem with it instead of a simple problem like resistors touching.

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    1. You are right. The resistors touching is a big a problem, and I think some times it touches under the board you can't even see it.

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  9. Good. You did not respond to your comments though.

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