Sound Activation

One of the aims of our project is to have sound play in recognition of the user recycling. Think of it as a reward.

The difficulty we were first placed with was how we go about doing this.

Method One

One method to produce sound would be to have the sound triggered by a motion sensor placed inside the bin. When items where recycled the motion sensor would trigger arduino to play a sound through the connected speakers.

This idea came from a precedent study found on instructables.com

Method Two

The second method was to use a pressure switch which would trigger sound.

The idea would be that the pressure switch would be placed on the spot where rubbish is placed to set off the hippo mechanism.

The problems we faced with this method was there was no guarantee it would work everytime, as the rubbish would need to be a certain weight to set off the switch.

This idea came from another precedent study found on instructables.com

Method Three

The third method was to have a light sensor built into the hippos mouth which would be sensitive enough to recognize when the mouth was open. However the major problem we were faced with was that the mouth may not be big enough to hold a light sensor and rubbish.

Chosen Method

Our chosen method is based on a precedent project on instructables.com

Our idea is to take the speaker from an audio birthday card and record our own environmental message.

Using a light sensor connected to a relay switch which is connected to the speaker, when the light sensor senses something in front of it it will tell the relay switch to turn on the power from the speaker to play the message.

The advantage of using a speaker from an audio birthday card is that it has its own supply power. By connecting a relay switch to the speaker means we can use the power from the speaker.