Monday, June 25, 2012

Potato Battery Driven LED

Potato Battery Driven LED
So, if you looked at my profile you would see that I like physics.  When the challenge for “Potatoes” I just knew that I need to do a project that highlighted the lowly “Potato Battery”.  So here is how to make a Potato Battery and have it light an LED light.

Step 1

Galvanized nails
Shinny copper pennies
Wires with alligator clips on each end (2+ per battery)
LED bulb
Multi meter
Cutting board

Step 2

  • PotBat 16.JPG
  • PotBat 17.JPG
A battery is a way to store electrical energy.  For a battery to work it needs to have 3 things, two electrodes (metals, one + and one -) and electrolytes (minerals).  The batteries we are going to make today uses the electrodes of copper (pennies, anodes, +) and zinc (galvanized nails, cathode, -) and the electrolyte of K (Potassium) that is found in potatoes.

Step 3

Take a potato

Step 4

and cut it in half. This will make 2 batteries.  Potatoes are juicy, which is part of the reason they can be made into batteries.

Step 5

Take a knife and put a slit in the potato and slip the penny into the slit.  Push as much of the penny into the slit as possible, you want just a little bit sticking out of the potato.  Push the nail most of the way into the potato,(at this point I cut the nails in half, so that they weren't so tall).  Do not let the electrodes touch, keeping them about 1 inch apart.

Step 6

Turn on the Multimeter and put it at the lowest voltage reading.  Make sure the red probe is in the + slot and the black probe is in the – slot.

Step 7

Use the red line to touch the penny in the potato and the black line to touch the nail.  You can read how much voltage you have available in this potato battery.  It reads .85 volts, not bad but not enough to do anything fun.

Step 8

To increase the voltage, you will need to create more potato batteries and wire them in a series (that means to connect the + electrode of one battery to the – electrode of the next battery).  So I created 3 more batteries from 3 more potato halves. 

Step 9

Then I used the alligator clips connected to wires and wired first 2 potatoes together,

Step 10

this time the voltage read 1.69 volts.

Step 11

Let's take a minute and look at the LED light.   It has one long leg and one shorter leg.  The longer leg is the anode (+)  and the shorter leg is the cathode (-).  I clipped the batteries to the LED light (+ to+ and - to-), no light, therefore, not enough voltage.

Step 12

I wired all four batteries together in series, and found what the total voltage is of the 4 batteries was 2.38 volts and I again wired in the LED light, again no light.

Step 13

Finally I wired six batteries in series and it had a 4.08 volt reading. 

Step 14

This time the light lit up!  Hurray!   Potatoes can be used as batteries.

Step 15

Have fun playing with your new batteries, maybe you would like to experiment with increasing current by wiring the potato batteries in parallel as well as series.  Good luck and Enjoy!

How to See in The Dark

How to See in The Dark
If you want to be able to see in the dark you can pick up a maglite and shine it every where you want. But if you don't want other people to know you are there you have to figure out an other way to be able to see using a lightbeam others can't see. in otherwords build your own night vision scope.

what do you need:
- a viewfinder from an old camera.
- an old 380 line black and white camera
- six Infrared LED's
- three 15 ohm resistors

Step 1The viewfinder

  • viewfinder.jpg
  • open-viewfinder.jpg
  • viewfinder-cable.jpg
The viewfinder I used for this night vision scope. Was taken from a CANON UC4000 V8 Camcorder. The Camera was broke but the viewfinder is stil very usefull.

The viewfinder used to be connected to the camera with 5 cables.
When I started measuring them I noticed that I just needed the first three cables those where.
- +5 volt
- Ground
- video-in

The viewfinder contains a 0.7 inch picture tube, a high voltage power supply and some calibration pots. The size of this module is only 2,5 x 5 cm.
Therefore the  high voltage power supply could for the picture tube could cause serious injury if you touched it.

This is why in attached new cables to those connection points en put the viewfinder back together.

Now our output device is ready.

Step 2The camera

After some searching I found a 380 line black/white camera in my garage which was solderd on a piece of stripboard and used a 5 volt power supply (thats nice the same votage as my view finder). This camera cannot see in the dark but it can see IR light (which is invisible for the human’s eye). So fore the record this night vision scope is not an image intensifier this scope needs an Infrared light source.

(Sometimes manufactors put a filter in the lens which blocks the infrared light when you work carefull jou can remove it as described in my Instructable Turning an old webcam into a Night vision cam

Step 3The illuminator

For the illuminator I used 6 High Power Infrared Emitter, type SFH4550.

Some specifics on these IR LED's:
- Current: 100 mA
- Wavelength: 860 nm
- Radiant Intensity: 700 mW/sr
- viewing angle: 3 degrees
- voltage: 1,5 Volt
- Diode Case t-1 3/4 (5 mm)

I used the stripboard that was attached to the camera as a base for my illuminator which i made by connecting 2 times 3 LED's in series (3 * 1.5 volts = 4,5 volts) to make it work in my system that has to run on 5 volts becaus of the viewfinder and the camera, I had to place a 5 ohm resistor before the LED's to make the powerdrop I placed 3 resistors of 15 omh in parallel.

Step 4Connect and enjoy

After connecting the viewfinder to the camera en connected all the power and ground cables I could see in the dark using the light of the Infrared LED's.

I am stil searching for a case to put it in and when i do I will deside what kind of battery i will use en design a circuit for battery power to the 5 volt working power of the electronics in my scope.

Images of the completed Night vision scope will be added after i have found a nice case to put it in.

Unforunatly i can't let you see what the image looks like when you look trough the night vision scope, But i can gaurantee that it works great.

Happy spying.

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