An LED flashing light bar is a bar with a row of LEDs that start flashing at one end of the bar and finish at the other. The pleasing pattern of lights that results makes these bars useful as decorations for cars and trucks, parties, and home bars. You may build your own flashing light bar at home, saving money while personalizing the LED colors.
1. Put the LEDs into the 40-pin chip socket. Space the LEDs so that you skip every second pair of sockets. This will give the bulbs room. Put all the negative leads on the same side, and all the positive leads on the other.
2. Turn on the soldering iron and let it heat up. Put the LED socket into the holes in the center of the small circuit board. Touch the tip of the iron to each lead of the socket with an LED in it while also touching the lead with the tip of the solder. When the solder melts onto the lead and board, remove the iron.
3. Remove 1/2 inch of insulation from each end of each of the wires with the wire strippers. Place the end of one of the red wires into the small circuit board next to an LED’s positive lead. Touch the solder and the soldering iron to both the wire and the lead at the same time to solder them together.
4. Solder the other red wires to the positive leads and the black wires to the negative leads. Tape the wires to the board with the electrical tape. Bunch then together a little way from the edge of the board and tape them into a bundle. You now have a bar of LEDs mounted on a small circuit board with a cable of wires coming out of the bottom of the board.
5. Put the 555 timer chip into the 8-pin socket. Put the 4017 counter chip into the 16-pin socket. These sockets will isolate the chips from heat while soldering their leads. Put the chips into the other perforated circuit board and solder them into place.
6. Put the resistors into the circuit board side by side in a row. Solder all the leads of one side of that row together. Solder a jumper wire to each end of this row.
7. Solder the bare ends of the red wires to leads 0 through 9 of the 4017 chip. Solder each black wire to one of the unconnected leads of the resistors.
8. Solder the unconnected ends of the two jumper wires to the “Gnd” leads of both the 555 timer and the 4017 counter. Solder a jumper wire from the “Out” lead of the 555 to the “Clk” lead of the 4017. Solder another jumper wire between the “RST” lead of the 555 and the “VDD” lead of the 4017.
9. Solder jumpers between “ClkEn” and “Rst” and between the “Rst” and “Gnd” leads of the 4017. Solder jumpers between “RST” and “VCC,” between “Disch” and “Thresh,” and between “Thresh” and “Trig” on the 555.
10. Solder the leads of the capacitor to the “Trig” and “Gnd” leads of the 555. Solder the leads of the 1 megohm resistor to the “VCC” and “Disch” leads of the 555.
11. Solder the negative wire from the battery holder to the “Gnd” lead of the 555. Solder the positive wire of the battery holder to the “VCC” lead of the 555. Put the battery into the battery holder and the flasher will start to work.