Saturday, March 11, 2017

Blog Week 8

Blog Week 8

Schematic drawing of the Rube Goldberg circuit (an explanation of each part of the circuit will be written below in the following pictures)

555 Timer with 1.3M ohms of resistance. The Output of the 555 is sent to the 74192 counter. We can alter the speed at which pulses are created by using more resistance.
The 74192 receives the input from the 555 and converts the pulses that are generated into binary numbers
The binary numbers are sent to the 7447 which converts the numbers from binary to actual numbers. These numbers are displayed on the 7 segment display
The 7 segment display will display the number that is being received. In example, for the above number "5" the 7447 is receiving 0101 from the 74192 which is binary for "5." Which means that it is the 5th pulse received by the 74192. 
I alter the circuit so that when 9 is displayed an LED turns on. This was accomplished by using an AND gate attached to the 7447. The AND gate is looking for two 1's before it was release an output. Using 9 as the goal number we can use the input pins D and A to obtain the goal. I also ran a diode from the AND gate's output to pin 2 of the 555. This prevents the 555 from continuing to count after 9 is obtained.
The AND gate's steady output is sent to a heat sensor and an OP AMP. The OP AMP is required in order to cause the relay to work. The Output of the relay is connect to a DC motor.
The DC motor then spins, and the wire at the end of it acts as a "blade" like as seen in a mixer.

Here is a video of the entire circuit with a commentated explanation 


The first issue I had in this lab was figuring out a way to make the circuit stop at a given number. I tried a few ideas. doing a little experimenting I noticed that if I ran an input into the comparator pin of the 555 it caused the circuit to stop counting. This gave me the idea to use the output of the AND gate to make it stop at 9. I used a diode to prevent back flow. Without the diode, the circuit just stops counting at whatever number it starts out on.

The second issue I had was a very simple solution. I needed to prolong the circuit long enough to reach the time requirement. I had to play around with the resistance of the 555 timer in order to make the circuit last much longer.


  1. Very well done. Well done using the diode to prevent back-flow.

  2. Very well done. Well done using the diode to prevent back-flow.

  3. Good job Alec considering you had to do the lab by yourself.

  4. I really like the top down photo's of the breadboard, it makes the connections a low easier to see. Schematic was done well also.