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Larry's Overdue Bill Warning System Needed Work

Article-Larry's Overdue Bill Warning System Needed Work

Larry's Overdue Bill Warning System Needed Work

Fido's out of the doghouse now, thanks to Larry's automatic mail delivery notification system. When the postman opens the lid of Larry's mailbox, a photodetector mounted inside the mailbox activates a light-emitting diode inside the house, notifying him that mail has arrived. A special latch circuit ensures that the LED stays lit after the lid shuts, and a pushbutton allows Larry to reset the circuit after retrieving his mail.

Are you a Gadget Freak? Allied Electronics would like to send you on a shopping spree of up to $500 on its website at Email Design News your proposed project (must incorporate electronic components and involve sensing, motion, timing, and/or networking elements) to [email protected], along with a description of how it works, and a parts list. If your project is selected, you'll receive the shopping trip of up to $500 and be featured in an upcoming edition of Design News.

Mail's Here! Parts List
Amt Part Description Allied Part #
1 Ceramic Capacitor, 1.0 muF 881-5236
1 Ceramic Capacitor, 0.1 muF 881-3486
1 RED LED 670-1065
1 NPN Transistor 935-0841
1 CdS Photocell 980-0105
2 Carbon Resistor, 22 k 296-6330
1 Carbon Resistor, 1 k 296-6314
1 Carbon Resistor, 10 k 296-6326
1 Carbon Resistor, 1 meg 296-6348
1 Normally Open Pushbutton 757-2305
1 CD4011 Quad NAND 735-1323
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