You're late for work. As you hustle out the front door, the furthest thing from your mind is the afternoon's dentist appointment that you'd scheduled last week. You'd have probably forgotten all about it — if you hadn't thought ahead by programming a home-built device to give you a voice reminder as you pass it on your way out.
Just record your reminder on the device ("Dentist at 3 o'clock," or "Pick up the kids at baseball practice"), set the timer for when you'll need to hear it — up to a week in advance — and from the set time forward, it will play whenever you walk near the attached motion sensor. Sure beats having to remember everything yourself.
|PIR Sensor Module||276-033||Radioshack.com||$9.99|
|.1 uF cap, 50 V||272-1069||Radioshack.com||$1.49|
|SPST pushbutton sw red||26623||Jameco.com||$0.66|
|SPST pushbutton sw blk||26649||Jameco.com||$0.7|
|Wire wrap socket||37411||Jameco.com||$1.19|
|LM555 Integrated Cct.||27422||Jameco.com||$0.29|
|1 farad capacitor||142957||Jameco.com||$4.49|
|Pot 500K with switch||263848||Jameco.com||$1.59|
|4 AAA battery holder||216339||Jameco.com||$1.55|
|Acrylic butter dish||104461||Clearlyacrylic.com||$7.95|
|1 K resistor||30BJ250-1.0K||Mouser.com||$0.22|
|470 K resistor||30bj250-470K||Mouser.com||$0.22|
|4.7 M resistor||66-RCO7GF475J||Mouser.com||$0.25|
1. Drill holes in your chosen enclosure, following the drilling template. Glue the speaker [A], microphone [B] and motion sensor [C] to the enclosure. Mount the buttons [D] on the outside.
A schematic diagram can be downloaded here.
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