It's working!

Our glasses are working! Although we found a funny mistake that we made while assembling both of the circuits, their second op-amps were disconnected! However, this is great as we can reduce the size of the two separate circuits to fit on one "breadboard" and make the device more portable (now it can be carried in a shirt pocket).

The weight is also not too bad, at around the same weight as the 9v battery it needs for power, here's some images of the final production of the SoundSense Glasses!

After this circuit board was reduced in size and wires run, we ran the wires to the glasses and attached the LEDs and microphones:

We then tested it out to see if it worked in this short video:

Finally, Tasneem and Peter modelled the glasses for us in class.

Some fun facts:

• After a capacitor had slipped out of the board it was reconnected in the wrong place and fried one of our LEDs, oops!
• We also fried a 2N4402 NPN transistor
• We spent hours attempting to find why the circuit wouldn't work at first, this is probably related to accidentally bypassing the second Op-Amp

Development phase

We started developing the circuit from the example and luckily were able to find all the components we needed in the donated electronics kit, saving us around $3 towards development costs. This is even luckier as otherwise we bought the glasses for $5, a microphone for $9.99, and a pack of battery connectors for $4.99, making the "total" cost $19.99, one penny short of the limit.

While trying to re-create the circuit from Instructables we tweaked the capacitors and resistors until it worked well with a 6v power source made from two 3V CR 2032 batteries.

After some hours of trial and error, were able to get the circuits lighting up to sound! Here is a video of our progress so far showing the varying light levels and 6v power source in action:

With the circuits working, we aim to bring the size down to fit on a single board. However, we have found some bugs/changes to be made in the final prototype:

• The 9v battery has better performance than the 6v supply, so this will be the power source of choice
• A variable resistor does not affect the circuit enough to accurately set sensitivity, so there will instead be a mechanical way to alter the angle of the microphones as needed.
• The LEDs are very directional, so these too will need to be adjustable to the viewers' comfort