Make: Electronics Chap 1 Exercise 5

When life gives you lemons, make electricity. OK…that was kinda corny.

The last experiment in chapter one presents us with an old school kitchen table experiment; making a battery from lemons.

For the exercise I actually had to run out and grab some supplies, mainly the lemons, lemon juice, and some zinc coated brackets from Home Depot. The brackets set me back about $2.50 for a pack of 4.

Overall, this exercise is an attempt to mimic the function of a battery. For this to occur properly, you must have the correct chemicals working for you, i.e., copper, zinc, and lemon juice. In regards to copper, nowadays US pennies are copper plated only. So to get the most out of each penny in the circuit, look for the brightest (newer) pennies that you can find. As far as zinc is concerned. Using a galvanized metal part coated with zinc works fine as suggested in the text. If you venture out to the hardware store just look in the aisle where the door brackets are located. The packaging should say something like “Zinc Coated“.

Out of all the exercise thus far, this is probably the most difficult in terms of achieving success and a little messy. However, the key is to take your time, secure the correct parts, and follow the instructions exactly as given.

For what its worth I was able to light my LEDs on the first try. So I’ll try to provide you with a few tips to increase your level of success.

1. Put your lemon halves into a small glass jar; helps to keep them up right.
2. Saturate your lemon halves with lemon juice from the lemon juice bottle.
3. Make sure that you are alternating between bracket and penny throughout the circuit.
4. Make sure that the brackets and pennies are close but not touching; a half-inch apart worked for me.

All in all this was a pretty cool experiment  for those who have never done anything like this before.

Exercise 5 Materials:
Lemons or Lemon Juice
4 U.S. Pennies
1 inch or larger zinc plated steel brackets
Test leads with alligator clips
LED (Low Current)

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