1. Indian Institute of Technology Hyderabad

2. Objective of the Project  Objective of the project is to device earphones which reduce the exposure of humans to mobile phone radiations which are continuously emitted and absorbed while we are in a mobile phone conversation.  As we know, these radiations cause a lot of health hazards. The way to avoid exposure is to stay away from mobile while talking. Is that possible? Yes. By using earphones, we place the mobile considerably far, for the microwaves to reach our head.  But, various experiments proved that even earphones radiate when we are in a conversation.  So, we come up with an idea, which involves only transfer of mechanical sound waves rather than transferring an electrical signal.

3. Communication through mobile phones is carried out by microwaves and radio waves. Audio signal is converted to electrical signal and finally sent to the cell tower in the form of microwaves carried by radio waves.  In turn, the tower generates radiations and sends the microwaves to its destination that is the other mobile. Thus a mobile phone radiates as well as receives microwave radiation to which we are exposed, when we are in a conversation. Long term exposure to these radiations is same as to keep our head in a microwave oven!!

4. Image courtesy: Google images

5. Using earphones reduces our exposure to these radiations! But various experimental results proved that radiations are emitted even from earphones and headsets which can affect us as shown previously. Image courtesy: Youtube video and Google images. Working of earphone speaker 

7. The idea of making this model has been inspired from a stethoscope. It consists of an air tube. To it, a microphone is attached. (As shown in previous image) The microphone circuit is similar to the mike-speaker sets used in function halls. The principle involved is “Sound travels in any hollow tube.”

8. WORKING OF THE DEVICE Any sound from the speaker of the mobile phone can be heard when the fixing end of one tube is placed near the speaker and the hearing end is plugged in the ear. The sound wave produced from speaker is directly carried into the ears by the tube. When sound is produced near the microphone, it is reproduced by the speaker to which a fixing end is attached. The second end of the tube is placed near the receiver of the microphone, so that the sound reaches receiver of the mobile phone. Thus sound can be heard by the speaker and also can be transmitted to the receiver effectively with out radiation as the mobile phone is placed far away. -  Hearing end Fixing end 

9. -Audio Quality: As the model is of a earphones, we need to reduce the pipe diameter as much as possible. To check this problem, we conducted a survey among people in the locality using pipes of different radii. Pipes having a larger diameter showed the problem of interference resulting in a poor quality. Where as, pipes having relatively smaller diameter could not catch the sound waves properly. So, we came up with a pipe of optimum diameter (among the pipes we have) for which, we got very fair ratings. Every 2 people among 15 gave 5/5, 6 gave 4.5/5, 4 gave 4/5, and 3 gave 3/5. - Audio leakage at the ends: Leakage can be avoided if the ends of pipes are fixed tight in their respective positions. As there are many models of mobile phones, the fixing end part can be designed according to the required mobile phone shape and size and can be fixed tight to avoid leakage.