Revised prototype

After testing we’ve decided to use a larger battery without a solar cell. The Lithium Ion Battery Pack – 3.7V 6600mAh remains charged for up to 100 hours, which we can replace with a charged battery (once a week for three weeks). We’ll also add a realtime clock module to turn the interface off overnight. The signal from the sensor has been changed from Analog to PW (pulse width modulation) running in to digital i/o pin 8, which we’ve found to be more stable then the analog input.

All of this simplifies the signal flow, makes it more stable and means the technology will fit into a smaller weatherproof enclosure with only one external line in from the speaker.

Our revised component design …