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DIY LED Chaser

Chaser circuits have light sources that light up sequentially. The light sources may be mini-lamps or LEDs. Some of their uses are for Christmas lights and for entertainment at festivals. To make a DIY LED chaser, use a 4017 IC, which is a decade counter. A decade counter is a switch that can count pulses. It can support up to 10 LEDs. The 4017 is normally activated with an external driver, such as a 555 timer IC integrated circuit chip. The 555 feeds pulses to the 4017, which then uses the pulses to drive the LEDs connected to it.

Things You'll Need

555 timer IC
Breadboard
Jumper wires
0.1uF capacitor
1.0uF capacitor
47k-ohm resistor
1M-ohm potentiometer
2 AA batteries
Battery holder
Piezo buzzer or speaker
Digital multimeter
4017 decade counter
10 LEDs
330-ohm resistor

Instructions

- 1
  Orient the 555 so that its notch faces left. Insert it into the breadboard so that its upper part falls into the upper half of the breadboard's upper section, while its lower part falls into the breadboard's lower section.
- 2
  Choose one row on the breadboard that will function as the positive voltage source, and choose another row as ground. Add a jumper wire between the chip's pin 5 and the positive voltage. Do the same for pin 4.
- 3
  Connect pins 2 and 6 with a jumper wire. Place one end of the 0.1uF capacitor at pin 5 and the other at ground. Add one end of the 1.0uF capacitor to pin 2 and the other to ground.
- 4
  Place the 47k resistor between pins 7 and 2. Add the potentiometer so that one end is at the positive voltage source, the other end is at ground, and its middle lead is at pin 7.
- 5
  Check to see that a signal is coming from pin 3. First, attach the battery to the holder, and place its red lead at the positive voltage source, and its black lead to ground. Temporarily add a speaker or buzzer between pin 3 and ground. Alternatively, place a jumper wire vertically at pin 3, and another jumper wire vertically at ground. Hold the multimeter probes against the wires and check the voltage. Remove the temporary devices, and the battery from its holder. Leave the holder attached to the breadboard.
- 6
  Insert the 4017 chip a short distance away from the 555. Its notch must face left, and it must straddle the upper and lower sections of the breadboard.
- 7
  Wire the 4017. Use a jumper wire to attach an LED to pin 3. It must be placed so that its legs are vertical. The LED's positive lead, which is indicated by the longer leg, must face pin 3, and its negative lead must be inserted inside a separate column. Use the same method to attach LEDs to pins 2, 4, 7, 10, 1, 5, 6, 9 and 11, in that order.
- 8
  Connect one end of the 330 resistor to the negative side of the LED at pin 3, and attach its other end to ground. Connect the negative sides of the remaining nine LEDs to ground.
- 9
  Connect pins 15, 13 and 8 to ground. Connect pin 16 to the positive voltage source.
- 10
  Add a jumper wire between pin 3 of the 555 and pin 14 of the 4017. Add the battery to the holder. The LEDs will turn on and off.

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