LED flash for mobile phones

How many times have you felt bad about the spooky images taken by your mobile phone camera? Well, nobody cared about the poor souls who were stuck up with a low-end mobile phone, which supports a camera but not flash. Most mobile phones today come with the flash too at economical price, but our focus was to complete a mini project which was somewhat unique, which many had not tried earlier (probably for a reason that its dumb!). Whatever, it would still be a good learning experience to design a product altogether from scratch.

Our requirement was to simulate the inbuilt flash in cameras by an external one. Basically, we need to turn on the LED flash exactly at the time, sensor is active and keep the LED on-time as small as possible(to save power). Our idea was to use the Camera ‘click’ sound that comes if the sound is enabled. the sound generated can be tapped by audio port of mobile phone and can be given as a trigger signal to 555 timer circuit, configured as monostable multivibrator. But unfortunately, the ‘click’ sound in Nokia phones is produced after the picture is captured. So, we went for a simpler way of tapping the keypad tone. After some amount of trial and error by adjusting RC for preferred duration of LED on, we could get it working. We used  two 3W LEDs in series to get light bright enough.

Then, the Industrial Design part of bringing up a proper mechanism to cling on to the phone, its adjust-ability were designed. With a few acrylic sheets, glue and some work in workshop, we came up with a nice box (bigger than the phone itself!). It fit well on the phone.

Its a pleasurable experience to design and build things however small or insignificant they are. Hope to build more things not just out of compulsion, but just for the sheer pleasure of it.


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