This is the traffic baton circuit which available in two versions that are traffic baton with LED flasher and traffic baton with bulb flasher. Both the circuits powered with a 6V, 4.5Ah rechargeable battery, which is clipped to the operator”s waistband. This circuit which come from EFY mag, will help the police or someone to regulate the traffic with hand signals at night or in dark condition. Since their hand signals may not be visible at night, it is necessary to have some illuminated direction indicator.

The image #1 displays the circuit of traffic baton with LED flasher. It uses an astable multivibrator to flash the LED, it similar to flipflof circuit. The “on” time of the LED cluster is about 108 milli seconds and “off” time is around 105 milliseconds. The frequency is around 5 Hz. A diode is wired in series with the base of BD140 to increase the forward voltage in order to ensure that when BD139 conducts, BD140 is cut-off. Select the LED which consumes low current (20 mA or so) but flashes bright.

The image #2 displays the circuit of the trafic baton with bulb flasher. Similar with LED flasher version, the timer NE555 is wired as an astable multivibrator. The “on” period of flashing bulb is around 344 milliseconds and “off” period is around 329 milliseconds. The frequency is around 1.5 Hz. Bulb-driver transistors 2N3053/ BD139 and 2N2905/BD140 are used to light up the lamp. Two diodes are used in series with the base of 2N2905 to increase the forward voltage in order Bto ensure that when BD139 is conducting, BD140 is cut-off. Slide switch S2 is used to change the colour status of the flashing bulb.

Build the LED flasher and bulb flasher circuits on separate general- purpose PCBs. Place the LED flasher in a transparent acrylic pipe as displayed in above images. The bulb flasher circuit can be enclosed in another transparent acrylic pipe. Slide switches and red and green acrylic sheets are used for appropriate colour emissions.

Good luck.

Components List:

This circuit will flash a bright or high-brightness red LED (5000+ mcd). Great for fake car alarm or other awareness getting equipment. Component values aren’t significant, attempt anything else first from the junkbox.Obviously, the 470 ohm resistor (R3) determines the LED’s brightness and limits the current flow to around 20mA. R3 value of 390 ohm can also be implemented as a save value.

If you determine to go with a green or yellow led, which take extra current, you might wish to change the 470 ohm with an proper value. Flash rate is determined by R2 and C1 and it is approximately three time constants (3*R2*C1). R1 provides bias to Q1 which should be low enough not to saturate Q2 with the capacitor disconnected. When the circuit does not oscillate, R1 may be too low or R2 too high. D1 allows for higher duty cycle operation and limits the feedback at the base of Q1 to -0.7 volts. D1 might be ommited for low supply power like 6 – 9V and low duy cycle operation.

LED Flasher 2-Transistors, circuit design by Tony Van Roon

Schematic diagram:

Component Parts:

R1_________ 100K
R2,R5______ 1K
R3,R6______ 470R
R4_________ 12K
C1_________ 1000uF 25V
D1-D4______ 1N4007
D5_________ SCR  P0102D
Q1_________ BC327
Q2_________ BC337
SK1________ Female Mains socket

How the circuit works:
The device formed by Q1, Q2 and related resistors triggers the SCR. The flashing frequency is provided by R1, R2 and C1. To change flashing frequency value, just? set C1 value from 100 to 2200uF, don’t modify R1 and R2.

Best performances are obtained with C1=470 or 1000uF and R4=12K or 10K. Due to low consumption of normal 10 or 20 lamp series-loops, very small and cheap SCR devices can be used, e.g. C106D1 or TICP106D.

Warning! : The circuit is directly connected to the 220V mains, please be careful when try and use this circuit

Source: redcircuits.com