Is It Ripe Yet? Build a Circuit to Detect Ripe Produce

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Gitti613
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Is It Ripe Yet? Build a Circuit to Detect Ripe Produce

Post by Gitti613 »

These are questions from 8th grade students who attempted to do the above lab for their Science fair project.

1. We built the 2nd circuit and the white LED lit up and we put a red object in front of the photoresistor, but the red LED light did not light up. We tried to adjust the potentiometer, but nothing changed.

2. Does it matter what color jumper wires?

3. Is there anything we should be careful about? Anything else we should be doing?
bfinio
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Re: Is It Ripe Yet? Build a Circuit to Detect Ripe Produce

Post by bfinio »

Hi, I am going to answer your questions a little out of order:

2. No, the color of the jumper wires does not matter. In electronics we typically use red for positive and black for negative. You can pick whatever colors work best based on the lengths of wires you have available.

3. It only takes one misplaced wire on a breadboard to prevent the entire circuit from working. Many times students who are new to working with a breadboard will make one or more simple mistakes when building the circuit. I have years of experience and I still make mistakes - the breadboard holes are small, and it is easy to be off by just one row.

1. This is a rather complicated circuit so my guess is that something is misplaced. If the white LED is lighting up then you know at least part of your circuit is working. Make sure you double and triple-check the wiring for the entire circuit. If you can send clear, well-lit, in focus pictures of your breadboard so we can see all the connections, we can help with this part. It usually helps to send a top-down view from several slightly different angles, since sometimes some of the wires can be obscured by other parts on the breadboard.

There are also a lot of different external factors (besides adjusting the potentiometer) that can affect the circuit, even if it is wired correctly. See steps 2-3 toward the end of the procedure. Did you try playing around with these different factors?

Hope that helps, please write back if you have more questions.

-Ben (author of the project)
Gitti613
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Re: Is It Ripe Yet? Build a Circuit to Detect Ripe Produce

Post by Gitti613 »

bfinio wrote:Hi, I am going to answer your questions a little out of order:

2. No, the color of the jumper wires does not matter. In electronics we typically use red for positive and black for negative. You can pick whatever colors work best based on the lengths of wires you have available.

3. It only takes one misplaced wire on a breadboard to prevent the entire circuit from working. Many times students who are new to working with a breadboard will make one or more simple mistakes when building the circuit. I have years of experience and I still make mistakes - the breadboard holes are small, and it is easy to be off by just one row.

1. This is a rather complicated circuit so my guess is that something is misplaced. If the white LED is lighting up then you know at least part of your circuit is working. Make sure you double and triple-check the wiring for the entire circuit. If you can send clear, well-lit, in focus pictures of your breadboard so we can see all the connections, we can help with this part. It usually helps to send a top-down view from several slightly different angles, since sometimes some of the wires can be obscured by other parts on the breadboard.

There are also a lot of different external factors (besides adjusting the potentiometer) that can affect the circuit, even if it is wired correctly. See steps 2-3 toward the end of the procedure. Did you try playing around with these different factors?

Hope that helps, please write back if you have more questions.

-Ben (author of the project)
bfinio
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Re: Is It Ripe Yet? Build a Circuit to Detect Ripe Produce

Post by bfinio »

Hi - I'm not sure if you intended to type a new reply here? It looks like you just quoted my previously reply in its entirety. If that was an accident, please let us know if you have more questions.

Thanks,

Ben
Aasrith
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Re: Is It Ripe Yet? Build a Circuit to Detect Ripe Produce

Post by Aasrith »

Hey, I have some questions on your project!
1. I have checked this circuit multiple times, even rebuilt it and the red diffused LED will not turn on even though I changed the potentiometer

2. Does the environment of where your testing this matter?

Thanks,

Aasrith
Aasrith
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Re: Is It Ripe Yet? Build a Circuit to Detect Ripe Produce

Post by Aasrith »

My potentiometer is also SUPER wobbly on my breadboard, do i need to get a new one or does this usually happen.
bfinio
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Re: Is It Ripe Yet? Build a Circuit to Detect Ripe Produce

Post by bfinio »

Hi:

1. Even when students assure us they have checked the circuit multiple times, many times when people send us a picture we still find an error in the circuit. If you haven't already it might help to have somebody else check the circuit - sometimes it is just hard to spot mistakes when looking at your own work. It's similar to proofreading your own writing for typos - sometimes they jump out at other people right away.

2. The ambient light in the room can affect the circuit, you might want to try in a darker room.

3. Have you tried a different LED? It's possible that you accidentally burned out the LED at some point and now it won't light up because it's dead, even if the rest of the circuit is correct.

4. As long as the three legs are still attached to the bottom of the potentiometer and haven't broken off, it should be OK. It's normal for it to be a little wobbly. If you have a multimeter you could confirm that the potentiometer is working by putting it in the breadboard and then measuring the resistance between each pair of pins. If the resistance measures as infinite (the multimeter screen shows "OL" or "1 ") then it isn't connected and something is broken.

Hope that helps!
Aasrith
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Joined: Wed Mar 02, 2022 3:32 pm
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Re: Is It Ripe Yet? Build a Circuit to Detect Ripe Produce

Post by Aasrith »

Thank You So Much! I have science fair in a couple of days and im trying to fix my circuit!
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