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.
Figure 1.3 Motor attached to table awaiting "9" on the BCD counter to operate
Figure 1.4 Relay connections with LED signifying the relay has switched
Figure 1.5 OPAMP with a gain of about 7, connections provide voltage for relay coil to switch
Figure 1.6 Temperature sensor connections, provides input for OPAMP
Figure 1.7 LED turns on when relay switches to signify the 555 timer is operating
Figure 1.8 555 timer connections, provides a signal to BCD counter to begin counting
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
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.