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This is an LED decade flasher circuit.
The circuit cycles through ten stages. It runs off 9V batteries and is enclosed in clear plastic to make it water resistant and make it fresh looking.
It can be attached to a bike, a messenger bag, a hat, lingerie, a back pack, anything you want.
If you've never done anything with a 555 timer before, this is a good circuit to start with!
To build this circuit, you need breadboarding skills, soldering skills, and to finish it in plastic, you need to sew or have someone sew it for you.
How does it work?
A 555 chip is used to make a clock that sets the beat for the HCF4017B decade counter.
The clock speed is adjusted by changing the values of the resistor and capacitor.
Bigger means a slower pulse time, smaller values make faster pulses.
The 10 outputs of the HCF4017B are connected to the bases of 10 NPN transistors (BC547s, or 2N3904s, both can work).
Each transistor drives 4x 500mcd LEDs at 9 volts.
This kind of LED is more efficient, running brighter.
If you use less efficient ones, then you can only load about 2 LEDs.
The circuit cycles through ten stages. It runs off 9V batteries and is enclosed in clear plastic to make it water resistant and make it fresh looking.
It can be attached to a bike, a messenger bag, a hat, lingerie, a back pack, anything you want.
If you've never done anything with a 555 timer before, this is a good circuit to start with!
To build this circuit, you need breadboarding skills, soldering skills, and to finish it in plastic, you need to sew or have someone sew it for you.
How does it work?
A 555 chip is used to make a clock that sets the beat for the HCF4017B decade counter.
The clock speed is adjusted by changing the values of the resistor and capacitor.
Bigger means a slower pulse time, smaller values make faster pulses.
The 10 outputs of the HCF4017B are connected to the bases of 10 NPN transistors (BC547s, or 2N3904s, both can work).
Each transistor drives 4x 500mcd LEDs at 9 volts.
This kind of LED is more efficient, running brighter.
If you use less efficient ones, then you can only load about 2 LEDs.
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Signing UpStep 1Parts List
All of the parts are easy to get hold of and inexpensive.
A few tips:
A pair of helping hands is vital, especially when you solder the LED array.
And heat shrink will protect you circuit, not only protecting it from short circuiting, but by keeping supplementing the soldered joints by providing a strong mechanical bond.
Use colours to code your wires. Red, black, pretty obvious. Green for signal. White for transistor to chip. It might sound a bit obvious, but I never used to do it this way, only after tech that I started forming this habit.
Tools
Helping hands (really useful! I couldn't have done it without these...)
Heat shrink tubing (at least 2km, in all sizes)
Side cutters, wire strippers, nail clippers.
Soldering iron
Dust/Gas mask
Parts
Black, red, white and green hookup wire.
555 timer chip
HCF4017B decade counter
1x 8 pin IC socket
1x 16 pin IC socket
10x 3904 or BC547 NPN transistors
40x 500mcd orange LEDS
1x green LED
1x 1000 ohm resistor
1x 4700ohm resistor
1x 10 micro Farad polarized capacitor
1x DPDT power switch
1x 9v PP3 battery clip
1 set of 2-way sockets and connectors, any type.
Packaging
Clear plastic material (go to a fabric shop)
Clear plastic tubing, 0,5mm (go to a hardware store)
Velcro strips (also a fabric shop)
What? Only one resistor needed? I'm not going to add any with the leds? That's right, and I don't need to. Four in row at 9v, and pulsed 9v also won't have too much risk of overheating and burning out.
Here are the data sheets for the two chips:
http://pdf1.alldatasheet.com/datasheet-pdf/view/8979/NSC/LM555.html
http://pdf1.alldatasheet.com/datasheet-pdf/view/133628/ETC/HCC/HCF4017B.html
A few tips:
A pair of helping hands is vital, especially when you solder the LED array.
And heat shrink will protect you circuit, not only protecting it from short circuiting, but by keeping supplementing the soldered joints by providing a strong mechanical bond.
Use colours to code your wires. Red, black, pretty obvious. Green for signal. White for transistor to chip. It might sound a bit obvious, but I never used to do it this way, only after tech that I started forming this habit.
Tools
Helping hands (really useful! I couldn't have done it without these...)
Heat shrink tubing (at least 2km, in all sizes)
Side cutters, wire strippers, nail clippers.
Soldering iron
Dust/Gas mask
Parts
Black, red, white and green hookup wire.
555 timer chip
HCF4017B decade counter
1x 8 pin IC socket
1x 16 pin IC socket
10x 3904 or BC547 NPN transistors
40x 500mcd orange LEDS
1x green LED
1x 1000 ohm resistor
1x 4700ohm resistor
1x 10 micro Farad polarized capacitor
1x DPDT power switch
1x 9v PP3 battery clip
1 set of 2-way sockets and connectors, any type.
Packaging
Clear plastic material (go to a fabric shop)
Clear plastic tubing, 0,5mm (go to a hardware store)
Velcro strips (also a fabric shop)
What? Only one resistor needed? I'm not going to add any with the leds? That's right, and I don't need to. Four in row at 9v, and pulsed 9v also won't have too much risk of overheating and burning out.
Here are the data sheets for the two chips:
http://pdf1.alldatasheet.com/datasheet-pdf/view/8979/NSC/LM555.html
http://pdf1.alldatasheet.com/datasheet-pdf/view/133628/ETC/HCC/HCF4017B.html
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http://www.instructables.com/community/Star-stasterisk-arrested-at-Logan-airport-for-bo/
Woah. That's pretty hardcore.
Okay, then a disclaimer is in order - don't wear near airports or overly-hopped-up security officials.
But LEDs last for a long time if powered up correctly. I had a few times where I had christmas fairy light effect because I had one LED the wrong way round, but if one strip isn't lighting up, troubleshooting 4 LEDs in series really isn't a problem. You can fix it almost instantly.
If you wanted to use only one LED per transistor, you'd need to give it a resistor.
I would worry that someone would think its an emergency vehicle-style 'turn indicator' or 'go this way indicator'...:D
Obviously though; visibility, even if POSSIBLY confusing is better than no visibility.
Ideally, it should have been mounted vertically, not horizontally.
My bag didn't have any other velcro placements at the time though.
Or maybe: confusing and trippy is better than no visibilty - the LEDs I used were rEaLlY bright.