Instructables

USB Traffic Light

Picture of USB Traffic Light
*Update I have made the PCB layout for this Traffic Light*

In this instructable I will show you how to make a USB Traffic Light.

Parts 
(1) LM555 Timer
(1) 10µƒ Electrolytic Capacitor
(1) 0.01µƒ Ceramic Disc Capacitor
(1) 1MΩ 1/4-watt resistor
(2) 4.7KΩ 1/4-watt resistors
(1) 1KΩ 1/4-watt resistor
(1) 10KΩ 1/4-watt resistor
(1) NPN 2N2222 Transistor
(1) USB Male Plug

The Picture of all the parts is in the next step

 
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Step 1:

Picture of
 All the Parts.

Step 2:

Picture of
 Here is the schematic.  Please leave comments & rate me. Sorry, the Schematic  made on word got messed up. I'll try to update it with a better one.
cdousley4 years ago
Cool project ,
Where did you get that momentary switch I ordered some like it but they are terrible for breadboards
Many momentary switches have leads that are bent to clip into a PCB and they don't work in a breadboard. With those you can take some needle nose pliers and pinch the leads flat. They'll come out straightened and will fit in a breadboard.
Mr_Electric (author)  PaulMakesThings3 years ago
The momentary SPST switch I used was actually designed for breadboarding. They might be on Digikey or Mouser somewhere.
Mr_Electric (author)  cdousley4 years ago
 I actually got that from a kit.  You could try Radioshack, but I haven't tried their momentary-open SPST switches yet...


Mr_Electric (author) 4 years ago
 Well The Switch starts the counting cycle (about 11 seconds) ,which lights the Red LED. The Green is basically connected to an inverter, which is connected to the Red LED output. To change it back, just press the switch. There really is no frequency because you have to manually  switch the colors. I'm working on an automatic one with a yellow LED. 
lemonie4 years ago
This toggles the red/green then?
At what frequency?
When I was a kid I had one of those electronics kits, the traffic light experiment had 3 bulbs and 3 switches...

L
Bongmaster4 years ago
so to be correct its USB "powered" ;)

kool use of a 555 tho :3 i got a few to mess with :P
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