This is a project I'm currently working on for my local combat robotics club. It is an LED light system that will signal the drivers when the match will start. Here are the goals I was aiming for:
- Physically appear similar to an older style traffic light that suspends in the middle of the intersection.
- Be controlled without a microprocessor (i.e. no Arduino)
- Internal power supply that can run the system for several days.
- Be protected from shrapnel and flying robots.
- Incorporate sounds as well as lights.
- Be very bright and look cool!
Testing at home:
A video of it in action (with brightness toned down):
- Physically appear similar to an older style traffic light that suspends in the middle of the intersection.
- Be controlled without a microprocessor (i.e. no Arduino)
- Internal power supply that can run the system for several days.
- Be protected from shrapnel and flying robots.
- Incorporate sounds as well as lights.
- Be very bright and look cool!
Testing at home:
A video of it in action (with brightness toned down):
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Signing UpStep 1: Circuit Design
Like I said earlier I wanted to accomplish the timing control without the use of a microprocessor. I'm using the 555 timer IC as it is simple to use and also very inexpensive as well.
The circuit is designed to have a momentary switch trigger the first light, and the next light is triggered when the first light shuts off. Repeat as necessary.
The schematic I've hacked together here (props to kpsec.freeuk.com) shows how I've wired the red and yellow portions of the circuit. You have to add an additional 555 timer 'section' for each light.
I used 100k resistors to get an approximate time of 1.1 seconds for each cycle. If you replace R1/R2 with a 1 megaohm pot you can easily vary the timing of your circuit.
A typical 555 timer can sink up to 200mA of current which is more than enough for a handful of LEDs. In my case I am using 36 LEDs per 555 timer which draw approximately 120mA.
The circuit is designed to have a momentary switch trigger the first light, and the next light is triggered when the first light shuts off. Repeat as necessary.
The schematic I've hacked together here (props to kpsec.freeuk.com) shows how I've wired the red and yellow portions of the circuit. You have to add an additional 555 timer 'section' for each light.
I used 100k resistors to get an approximate time of 1.1 seconds for each cycle. If you replace R1/R2 with a 1 megaohm pot you can easily vary the timing of your circuit.
A typical 555 timer can sink up to 200mA of current which is more than enough for a handful of LEDs. In my case I am using 36 LEDs per 555 timer which draw approximately 120mA.
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(4017 pins
light1 = output0
light2 = output1
reset on 4017 = output2
not gate(in) = output2)
(NOT gate chip
the output of the not gate is to the power of the 555 and the input is connected to output2 on 4017(if using 2 lights))
to output up to 8 lights then you only need 3 IC's
Have output 1 light up 1 led through a diode
have 2 output 1 and 2 led through another diode
/..etc
have output 4, 5, 6, 7, 8, 9 output to the 'green' led only, through a diode each.
http://bowdenshobbycircuits.info/page10.htm#traffic.gif
That follows the same idea, but uses a few transistors and runs a standard setup.