Monday, April 3, 2017

Joey's Week 12 Blog

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

Figure 1: Computer drawing of RG setup

2. Explain your setup.

The circuit starts with the force sensing resistor triggering a transistor to switch channels and using the diode the relay sends current to pin 2 from the pin it switched to in order to continue to flow after the transistor no longer sends any voltage. From here, voltage is sent to the X-OR gate where it is met by another input from the other very similar portion of the circuit. While the first relay sends a 1 to the x-or the x-or sends a signal to the op-amp that is then amplified and sent to the dc motor which pulls a lever on the built set-up pictured below that lets the marble run. Once the marble reaches the bottom it hits another force sensing resistor that triggers the second relay and sends a 1 to the x-or gate which then has inputs of 1/1 and then stops giving output to the motor. The transistor after the force sensing resistor can be used to trigger the second part of the RG setup.

3. Provide photos of the circuit and setup.

Picture 1 of circuit

Picture 2 of circuit (X-or gate)

Picture 3 of circuit. This is where it starts.

4. Provide at least 2 videos of your setup in action (parts or whole), at least one being a failed attempt.

Failed attempt

Succesful attempt

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

A lot of failures occurred this week. I had trouble and came to the conclusion i was using incompatible components because the X-OR gate could not reach a reading of 0-0 and then remain stable while going to 1-0. I think this was because I had the op-amp feeding into the x-or gate and the inputs of the logic gate were drawing voltage from the op-amp even when it was supposed to be given 0. After removing the op-amp and getting a new x-or it worked as planned. the op amp was placed after the x-or to give the motor enough power. the other issues faced were regarding the structural integrity of the cardboard coaster. after reinforcing with some duct tape it worked much better.


  1. Technical circuit drawing is nice. I want something similar for mechanical part as well. Mechanical structure looks ok but am not sure if it is complicated enough. Cannot tell from the video.

  2. For Joeys circuit, I like your marble tower design although I noticed that it fell off the edge on a failed attempt. Adding a larger lip to the track might help keep it more stable when dropping down.

  3. I liked this and how it using the X-OR gate to start and stop the motor. using the force sensing resistors as a type of switch and how you did that with the relays and transistors is cool.

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  5. I give you credit for using both transistors and relays to switch and also multiple motors and force sensors. I was having some difficulty using both transistors and relays with my setup.