BS-1 Universal Led Flasher


By Peter Giling

Many items in the market give a rather poor method of Leds just going on and off.

This very small unit is more than that.

The ready made and available printed circuit measures only 27 x 17 mm.

The double sided and through-hole metalized board contains a small microprocessor.

This makes it possible to have a selection of different programs for various tasks.

The firmware can be extended with more selections, if somebody comes up with a good suggestion.

For now, there are 10 available programs.

Program selection is made by installing a little jumper on board.

The board also contains the necessary resistors to connect LEDs, so all you have to do is connecting LEDs and power, nothing more.

The selected program will be remembered and start anytime you power up.

Power can be from 9 to 16Vdc, and power consumption is extremely low.

But you will be surprised about the quality of the light patterns it will give you!

Professional made pcboard is available for € 1,– (excl shipping).

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Also for any other question regarding this unit or MGV-loconet modules ask Peter.

Technical description

The unit is build around a Microchip PIC12C675.

The program is written in PicSimulator IDE Basic, from

The supply is no more than a transistor and a Zener diode.

It is made in such a way, that swapping the connections of power does not harm anything.

The 5 connections for LEDs all have a resistor on board so LEDs can be connected directly.

For all LEDs there is only one common (-).

The connection marked #5 is used as input for programs 7 & 10 to activate the second function In program 9 (dutch AKI railroad crossing) this enables the choice between 2 flashing red LEDs or 1 white slow flashing led.

In program 10 (german railroad crossing with barriers) Pin5 is used to activate the lights and barriers. Pin3 and 4 (and 6(-))can be used to connect MGV136 for powering barriers.

Program selection is done by putting on jumper and take it off again.

Each time the jumper is attached, the program will shift to the next one. For some programs (program 7..10) this might take a short time.

After removing the jumper, the selection is stored in internal EEPROM memory.

Available programs

Description (up until now (sept 20, 2010) Used LEDs 1st task Used LEDs 2nd task Used LEDs 3nd task special remarks
1 Nightrider All 5
2 2 independent flashers for police cars 1 and 2 3 and 4 use blue leds
3 2 independent working turn light flashers 1 and 2 3 and 4 use orange leds
4 High tower flashers All 5
5 Traffic blockade All 5
6 Normal flashers for dangerous road crossings 1 and 2 3 and 4
7 Traffic lights (dutch pattern) 1 Red 2 Yellow 3 Green
8 Traffic lights (german pattern) 1 Red 2 Yellow 3 Green
9 Railroad crossing Dutch type (lights only) 1 White 2 Red 3 Red connect pin 5 to ground to change pattern
10 Railroad crossing German type (with barriers) 1 Yellow 2 Red 3 cmd barrier enter, 4 cmd barrier exit. For Servo driven barriers, use MGV136
11 Welding flashes 1 blue

New features for BS-1

New developments have been coming up, to make the BS-1 useful as a 2,3 or 4 colour sign with leds.
All leds will be dimmed 'as real'.

Read this manual for further options.
All .hex files are in includedhere

The real thing

The Hardware

The schematics
The pcboard and parts position
N.B. Self made pc-boards are not supported!

more questions? ask peter

The Firmware


Qty Reference Part
5 R1..5 resistor 270 Ohm
2 R6,R7 resistor 10 KOhm
1 D1 Zener diode 5V1 400 mW
1 C1 capacitor 100 nF
1 T1 Transistor BC337-40
1 U1 PIC12F675 DIL8
1 Socket DIL8
1 Jp1 header 2 pins + jumper
1 J1 PSS254 / 2G
1 J2 header 6 pins

Diode position

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