Sunday, March 12, 2017

week 8

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.
Photo1.1: shows the entire circuit

For our Goldberg project, we almost used the same circuit as week 7 but we added on it. our circuit starts with connecting a 5 volts source to the the temperature sensor, then by heating up the temperature sensor with a hair dryer it will send maximum 1 V to the operational amplifier which will amplify the 1 volt that is coming from the temperature sensor, we connected a 10 V source to the non inverting amplifier so the amplifier will amplify the voltage to reach 6.87 V which is the voltage needed to switch the relay, when the relay receives the voltage it will switch from pin3 to pin4.
 Photo1.2:explains the process of the temperature sensor,
the operational amplifier, and the relay.

Pin 4 of the relay is connected to the 555 timer and when the relay switches from pin 3 to pin 4 the voltage will go through the 555 timer and by connecting the output of the 555 to the decimal counter  the voltage will go the decimal counter and it will be connected to the XOR gate and the display driver. 
Photo1.3: shows the operation of the timer and decimal counter. 
Now we connected the Qc and Qd to the input of the XOR gate, and then we connected a small motor to the output of XOR gate,we connected an LED light to the output C of the decimal counter and to the 5 V source,, at the same time we connected Qa,Qb,Qc,Qd  of the decimal counter to the inputs of the display driver(A,B,C,D) and then we connected the outputs of the display driver to the 7-segamen display. 
table 1.1: shows how XOR gate works
Picture 1.4: shows the outputs of XOR gate

Photo1.5: shows the operation of decimal counter connected to XOR gate and display driver while it is connected to the 7-segament display

As it is proven in the table above when the XOR gate is connected to the the outputs C and D of the decimal counter, the motor will be on when the 7-segament display is between 4 and 9 and it will be off between 0 and 3, Also because we connected the LED light to the inputs of the XOR gate, the LED will be turned on whether the motor is on or off but when the 7-segament is between 0 and 3 the LED light will be brighter. 

Photo1.6: shows the connection of the motor and XOR gate 
Video 1.1: explains the operation of the entire circuit

when the motor runs it will pull a string that is connected to a gate then the marble will go down the ramps until it hits some Dominos. 

Problem we faced in out rube Goldberg project:

Video 1.2: explains our failed Goldberg project

when we heat up the temperature sensor a maximum of 1V will go through the amplifier and then it will amplify it to certain value so the relay will switch but First problem we faced was that we couldn't get the amplifier to reach 6.87 V to switch the relay and even if we applied 10V to the non-inverting amplifier still wouldn't reach the 6.87 V to switch the relay. We solved the problem by using LM324 amplifier which can exceeds 5V easily and the reason the other amplifier wasn't able to reach this value was that it wasn't strong enough to amplify 1V to 6.87V. Another problem we faced is that we used one voltage source to XOR gate and because of that we couldn't use a big motor and we had to use a small motor, the reason is that the current that flow in the XOR gate isn't enough to run a big motor and I also think that the majority of the voltage will go to the decimal counter. Because of this issue, our project  failed and the motor was't strong enough to pull the string to open the gate and we didn't have time to fix the problem, next time we will test our project before the due date to make sure no such issues papers. 

Picture 1.7 drawing of circuit schematic 



  1. What channel did you use to power your motor(fixed 5V or the channel A or B)? I know with our Rube Goldberg, our AND gate was able to provide enough current to power our motor. I believe we used the 2 amp channel to power our motor.

    1. We used the fixed 5v channel to supply the digital circuit part of the circuit which then supplied our motor. We were sure if the circuit could handle a higher voltage to power a bigger motor.

  2. I like how you guys setup your Rube Goldberg. The idea behind the actual project is really good and you can definitely build off that for your final project. I was wondering If you guys got it to work at the end? also what power did you use and what type of motor?

    1. Thanks unfortunately we still could not find a way to get enough power to power a bigger motor to activate our machine. We were using the smallest motor the class had just because the bigger ones needed to much power to operate.

  3. Good blog. I wish it worked fully.