Blinking Courier Bag Light




About: I like to tinker with just about anything, sometimes it works out in the end. Have fun looking at the projects, try tearing something open and let me know how it goes. cheers, -Joe

This simple LED light can replace the reflector hang tags that everyone loses from their timbuk 2 courier bag.

It uses a 555 timer to alternately flash each set of 9 LEDs, for 18 blinking LEDs of goodness.

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Step 1: Parts


4 AA Battery holder
PNP Transistor (3906)
NPN Transistor (2222)
555 Timer
150k resistor
4.7k resistor
1uF Capacitor
160 Capacitor
220 Capacitor
19 LEDs
2 x 3./4" Quick relase
12" of webbing
2 x molex KK connectors


Soldering Iron
thread and needle
wire snips

Step 2: Cut Out the Straps

Cut your straps to the same length as the original reflector tags, which is about 5" and leave a small tail to put through the quick release.

Sew it together so it will nto come out of the quick release

Step 3: Build and Test Your Circuit

So I the circuit used is a 555 timer circuit, the one I like the most is on Bill Bowden's web site: Build it out on the breadboard and see how it works.

Step 4: Solder It Up.

Solder everything together.

Here I used two molex KK connectors, one for each set of LEDs.

Step 5: Time for the Flaps

So here I just poked the LEDs through the webbing, make sure all of your negatives are on one side.

Then cut 2 18" lengths of wire. Strip enough off of the end to cover all of the LED negative pins and then solder them each to the wire.

Do the same for the positive side.

Here solder on the female molex KK connector and the snap it on to your breadboard.

Do the same for each side.

Step 6: You Done.

Your done son, have fun.

You can see in the other pics how it fits in the bag.

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    8 Discussions


    9 years ago on Introduction

    Compuserve is gone forever anyone know a good place to find a 555 timer circuit for flashing LEDs  i am looking to build some turn signals

    2 replies

    Reply 9 years ago on Introduction

    The internet archive to the rescue!


    Reply 9 years ago on Introduction

    Awesome thanks.  4.7 cycles per second seems a bit fast, it this circuit is for more for "Notice Me!" and I'd have to do some reconfiguring to make it into a usable turn signal.

    But still a fun project thanks !


    10 years ago on Step 1

    hey, which led did you used? i mean the mcd rating.thanks, Etay


    11 years ago on Step 1

    160 and 220 are resistors...not capacitors.


    13 years ago

    My guess is this wouldn't go over real big at airport security. Beautiful, though.


    13 years ago

    What would happen if it rained while you had this powered on?

    1 reply

    Reply 13 years ago

    Hello there Mr Penquin - My experience has been that there is no effect. The circuit board is kept inside the bag, most of the bike messenger bags are waterproof. Let me know if you make it, this one I use to commute quite a bit and have been real happy with how bright it is. -Joe