Ohm-y!

Simple Op Amp Circuits


Simple Op Amp Circuit from Andrew Garza on Vimeo.

We are currently learning about Op Amps at school and I just wanted to mess around with an easy circuit. This circuit gets a zero on  both the practicallitly and efficiency scale, but I just wanted to experiment. What better way to learn? Anyways, I knew that the DC-motors could generate energy just by turning the top, but that voltage really isn’t large enough to power anything. So with an op amp I just increased the voltage or energy put out by the DC-motor. Since you can twist the motor 2 ways, one way putting out a negative voltage and one way with positive output voltage. The LEDs glow accordingly to which way the motor is turned.

I also hooked the output of this to a piezzo buzzer and a smaller DC-motor. The next thing I want to try is using magnets for the voltage in as an energy source.

posted : Sunday, March 15th, 2009

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Re: Transional LED (Reshot)

Transitional LED (Reshot) from Andrew Garza on Vimeo.

Just wanted to repost this in a better video quality. Again the flickering isn’t apparent while it is running. I just think that the camera capturing at 30-fps catches it (It is like when you try filming an old tv on camera). I still don’t think that this video does this justice. It looks much prettier in person.

posted : Wednesday, March 11th, 2009

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Re: 3-5 Volt Power Supply

I just wanted to state that the power supply I made 2 projects back is an epic fail. I don’t know what it is but it seems that a the thing doesn’t output a lot current so a lot of the circuit I have tried to power, don’t work properly. It was a fun build, but I don’t plan on attaching it to any of my projects.

posted : Wednesday, March 11th, 2009

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Binary Counter

Binary Counter from Andrew Garza on Vimeo.

Binary counter programmed with BASIC Stamp microcontroller. I guess I cut the the code one counter short because it doesn’t make it to the 64-th bit. I just didn’t feel like haveing to re-record it, but you get the idea. The code I wrote is easily expandable so I could add more LED’s to display more bits. Enjoy.

posted : Wednesday, March 11th, 2009

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3 or 5-Volt Power Supply

This appears to me to be my first legit project, and dare I say the one that I am most proud of yet? No, it isn’t anything special, but this project seemed more involved tech wise than others and when I was done, it worked exactely how I wanted it to.

I subscribe to the MAKE podcasts and on their How-To-Tuesday episodes on 1/28/09, he assembled a Plug-in-Bread-Board Power Supply. Then after some thought I figured that I could really just build the circuit myself, and so I did.

After picking up a variable voltage regulator, I built the circuit on a bread board to see what resistors were need to change the voltage out. Also after reading that data sheet from National Semiconductor, I read that the capacitors that were in the ‘How-To’ build, didn’t really need to be there. Also in there build they had there voltage out being 3.3 or 5 volts. So to determine the needed resistance I used a potentimeter and my multimeter to measure the voltages.

(I forgot about the 3.3 so I was just aiming for somewhere around 3… Oops.)

After assembling and find the needed resistance, I just soldered it all on a board from Radio Shack. One other thing that I happen to like about my build is that I just us a switch to change the voltages. For Make’s power supply they use a jumper which just seems like a little bit more work to change the voltage. I used a SPDT switch that changes the flow of current through to independant sets of resistors. (Just see TOP photo).

(Solder work could be better, just never worked with these boards before. Figuring out how to lay everything out was a challenge/fun.)

Once it was all soldered I just wanted to check and make sure I put in the correct resistors accordingly. I plugged it in and check the voltages.

(The final result…)

If you notice, the board just sits and plugs in so nicely into the breadboard. The only thing I had to do was line up the plugins. If you notice you can see a resistor located on either sides. If you look close enough to the solder work, on the picture above, the resistors aren’t being “used”. Both of their ends are connected and are just there to provide a solid connection to the bread board.

This is a project I would like to rebuild another time. For starters I would like there to be a power switch. Right now, the second you plug it in, it is live. Also, I wish I would have thought about adding a 2 LED indicator lights letting me know which power side is running. Another adjustment I might have done would have been to put a potentionmeter in there so I could always manage and change the voltage. Then again in order to actually know the voltage I would have to measure it everytime.

(3V on the left and 5 V on the right.)

posted : Wednesday, February 4th, 2009

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Organizing my Resistors…

Well instead of going out and partying with my Ultimate team this is how I spent my saturday…

First It took the time to sort out and mark all of the resistors. I kept them organized from lowest to largest resistances. Thankfully I have the iResist app for my iPod touch so it made this process go by much quicker.

Next I sketched out what would become a pouch for the resistors to be place. I knew I didn’t have enough compartments in my tackle box to keep the resistors seperate.

After getting about 70 of these pouches cut out I folded every one…

After folding everyone I went throw a glued them all. I thought tape would hold much better but I knew it would take twice as long to do and I was already 2-3 hours into this project.

Now the only thing left to was label and put away every resistor.

God damn my OCD. I don’t know, this whole thing might have been completely unecessary and probably was. Oh well, when I need a resistor or buy more then it will be nice and organized and easy to find. This took 4-5 hours of just sitting on my uncomfortable futon with my back bent/hunched over my coffee table. My back feels wonderful. Now I need to find a place to put all of these because they no longer fit in my tackle box…

posted : Sunday, January 18th, 2009

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Solder Fume Extractor (Failed)

So I saw this idea on a podcast from Make. The idea is to blow the fumes produces from the melting solder out of your face. Don’t get me wrong, I enjoy enhaling them, but they are no good for you. Anyways, the only thing that I didn’t have was the mesh screen so I figured just drill a bunch of holes in the box. Anyways once all hooked up alls it seemed to do was just blow the fumes around. Maybe someday I will come back to this project but I don’t see a need to. I just had a old fan and battery laying around.

posted : Thursday, January 15th, 2009

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Scrolling Double 7-Segment LED


Scrolling Double 7-Segment LED from Andrew Garza on Vimeo

I just recently bought some dual 7-segment LEDs. I just wanted to mess around and figure out the layout of the inner LEDs. Unlike my last dual 7-segment LED,  the all share a common input, instead all sharing a common ground. I wanted to figure out how the dual 7-segment LED so I can try and integrate it into my temperature sensor. That way I can have it display the temperature. The only problem is that the dual 7-seg takes up every pin… I need to design a circuit with some logic gates…

Anyways, just playing around with the dual 7-seg I decided to make a scrolling marquee. Here is the code below. It is super sloppy and I don’t think I would have ever programmed it like that again. The variables correspond with the dual 7-seg pin layout.

Here is a picture of the pin layout:

posted : Sunday, December 14th, 2008

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Transitional LED


Transitional LED from Andrew Garza on Vimeo

Here is an actual video taken recently of the transitional LED. The LED is really blinking really quickly changing colors back an forth. This really isn’t noticeable in person, but when taken with camcorder, it is apparent.

posted : Sunday, December 14th, 2008

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Full Color LED Transition

A month ago I picked up a Full Color LED from Radio Shack. Right off the bat, and noticing only four pins, obviously the LEDs colors were going to be red, green and blue. WIth these three colors I knew I was able to acheieve any color. The next weekend, I decided to try and plug it into my microcontroller but didn’t have any luck. I could not figure out how to increase or decrease the brightness of the LED. I knew the only way to do this would be to raise or lower the current flow. I didn’t have any variable resistors, except for a pontentiometer and I didn’t want to transition to be manual. After getting the LED to flash in weird patterns and not acheiving my overall goal, I decided it was time to get some sleep.

Recently watching a video on the Arduino, I saw a tutorial of a simple demonstration of the microcontroller. The tutorial was what I was looking for. They made an LED fade in and fade out. Looking over there code, I went to compare it the BASIC Stamps code. The syntax was practically the same. After some trial and error I finally came up with the code for the LED.

The schematic:

With this code and set up, the LED works great. There doesn’t seems to be any hiccups during transitions. The color changes are all very fluid and changes seemlessly. I wish I had a video camera to record the result, but my D40 is all I have.

posted : Wednesday, December 3rd, 2008

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