5 Tricks You Did Not Know You Could Do With Cell Phones

Adam Beehler

In each newsletter, Adam Beehler, Lecture Demonstration Specialist, explains one of his demonstrations.

I wanted to follow in the same vein as last edition’s, “5 Things You Did Not Know You Could Do With Lasers” - simple, fun, and practical for just about anyone. I have been using some of the following tricks for years and people seem to be amazed when I use them. I think it is time everyone knows and uses some of these tricks, as they are both neat and very useful in certain situations. For materials, I just used a regular cell phone with a camera capability..

1) “Listen” to its Radio Waves

(EM Wave Emitter)

Handheld radios pick up radio waves - go figure. These electromagnetic waves are emitted by many different sources, other than just your favorite radio station. A cellphone should be an obvious choice as such a source. So tune your radio to some static noise, so that one radio station does not dominate the signal. Then simply walk around and hold the radio up to different sources to “hear” the waves they are emitting. You might be surprised which objects give off so many radio waves. To help hear a signal more clearly, you may need to slowly scan through the AM and FM ranges. You may also slowly re-orient the radio next to the object in question. Try your cellphone in its different modes - GPS, WiFi, Bluetooth. Some other suggested objects to “listen” to are transformers, spark plugs, and calculators while computing.


2) IR Tester

(Check your Batteries)

Your remote emits infrared light (IR) that your eyes cannot detect, but most digital cameras can see it quite easily. Just aim the camera at the top of the remote, and push a button on the remote while looking into the camera. If the batteries are dead you wouldn’t see any light emitted from the remote control.


3) Polarizer Detector

(A Source of Polarized Light)

Most cellphone screens utilize polarizers to allow users to see what the cellphone wants them to see and not extraneous glare and reflections. What this means is that the light emitted from your cellphone is polarized light. Ergo, you have your own polarization detector, too. This emitted polarized light can become unpolarized though as it passes through a screen protector, so to see this effect, you may need to lift your screen protector. You can now verify whether or not those sunglasses are really polarizers or not, by looking through one lens of the glasses at your cellphone screen. Simply rotate the lens (or phone) and see if light becomes blocked. Since most glare is horizontally polarized, polarized sunglasses have their polarization axis vertical. Knowing this, you can determine the polarization axis of your cellphone screen, which could then help you determine the polarization axis of another polarizer later. You can also now insert different transparent objects in between your cell phone screen and your polarized sunglasses and see if the object affects its transmitted polarized light or not. Here is a picture of the
stresses seen in a pair of normal eyeglasses.


4) Point of Reference

(Ruler + Scale)

Have you ever been in a situation where you needed to do a quick measurement or quickly judge the weight of something small? One trick is to use your cellphone as a point of reference. This makes sense, as many people keep their cell phones with them all the time, and it is very handy to use when you are in a spot. I weighed my phone on a postage scale and used a ruler to figure out the size. Then, I just rounded those results to the nearest easily-remembered number. My cell phone weighs about a quarter of a pound (4 ounces or 120 grams). I also know that my cell phone is roughly 5 inches tall, 2.5 inches wide, and nearly a half an inch thick. With these measurements in mind, I can more accurately judge the size or weight of something without having to cart around a ruler and scale.


5) Microscope

(Image Magnifier)

Holding about any cheap lens in front of the camera will get one closer (and thus more magnified) images. I even tried a water drop on the camera’s lens and it worked (although I cannot attest to your camera’s waterproofness, so I do not suggest trying it). In the picture above, I used an old telescope eyepeice. However, you can use anything from a magnifying glass, the optical lens from an old CD player, or even the contact lens cases with the magnifying glass on the lid (this one is neat because it gives you a microscope and a fish-eye lens in one unit).



6) Detect Health Problems

(Health Analyzer)

Okay, I realize this one is not quite available to everyone yet. I threw this one in here because it was really neat and it will not be long before everyone will be able to spot health problems using their cell phones. Most people are already aware of the “Red Eye Effect” where pupils appear red in photographs of eyes. This is caused by light reflecting off the eye’s retina, making the eyes appear red. However, sometimes only one eye appears red, and the other eye appears white (see above image). This is often an indicator for many dangerous health problems including melanoma and retinoblastoma - very dangerous cancers. There has been research into other devices that connect to your cell phone that can also detect cancers, malaria, and diabetes from your breath; test water quality for pathogens; andmonitor lung function in patients. The aim of these devices is to be low-cost, easy to use, and to save lives by detecting serious health problems earlier and getting treatment sooner - to which I think we can all agree is incredibly innovative.

You can also view this demo, and a complete materials list, here.