some of my friends including me have made D.I.Y spot lights for our bicycles but as usual they got jealous watching other branded lights.
Why? Because those lights have a strobe function! lol
Each of my friends have made he's own light with different configuration housing, bulbs, batteries, operation voltage and amperage. So, I needed to build one circuit to fit in every light with no extra effort. Here is the answer, the 555 IC it's the perfect cheap choice and it will do the job for all the lights. Off course we can buy ready made ones and also cheaper but making your own from the scratch it's fun.
Also i would like to point out that the uses of these little things are endless. it can be a bicycle strobe light, christmas lights, car strobe light and so on. Just use your imagination!
A few words about the mighty 555 IC.
It can operate from 3VDC to 16VDC MAX. It can deliver 200mA output from pin 3 so it's ok to drive a few typical led.
Even so, 200mA it's the maximum output therefore the IC safer at MAX output, no good!A better solution is to use a transistor to deal with the LOAD driven from the 555 IC and let the second do it's job and by that I mean, the counting for the strobe operation.I'm not gonna go any deeper concerning the operation of the 555. There is plenty info out there if someone who is interested to learn everything about the 555's operation. My intention is to help the beginner to make his own 555 strobe with basic info with less confusion, I hope!I will be happy if I can help with this instructable.
So, lets get started...
Add a boost to your 555
OUTPUT LOAD & TRANSISTORS - which one is the best for the job?
Here are some transistors from Low-power to Hi-power where can be used in this case.
LOAD = is the Amperage (A) the bulb,led draw when is on. 1A = 1000mA.
For 200mA LOAD => BC547 NPN
For 500mA LOAD => BC337, 2N1711 NPN
For 1,5A LOAD => BD135 NPN
For 3A LOAD => TIP31,BD241 NPN
For 4A LOAD => BD679 NPN
For 5-15A LOAD => TIP3055 N-gate (it is NOT recommended for this article's PCB because the traces are too thin and too close to each other to handle 5A > load).
Tip: never use a 500mA transistor for 500mA load without heat sink. It's best to use 1A transistor instead.
Soldering iron. Not more than 25W
Solder Wire 0.5mm – 1.0mm will do
Jel-flux for the soldering
Small wire cutter
Drills = 0,7mm mainly & 1mm for the wires and the Q1 transistor
Mini hobby Handheld drill machine