Generally cars have right turn and left turn signals which are given out by blinking 12V bulbs fixed at the rear of car. These are operated by hand control at the steering wheel. To make them effective, quite a lot of power is used up. Still it so happens that the drivers at the rear may not make note of this, as they are a bit way down the car. We have here a novel, cost effective and energy efficient signaling display, which can fixed near the rear window or so that it becomes extremely visible.
The circuit is shown in Schematic 22. This is another application of CD4017, decade counter. Two identical circuits are built here one for each direction. The advantage is that they can be built straight into the left; right signal lights and power can be taken from them without additional wiring from the steering wheel.
Clock pulses to the IC are supplied by good old 555, which can be adjusted by 100K (R2) preset. CD 4017 divides these pulses and outputs are available at Q0 to Q9. Each output drives a Red LED. All these ten LEDs are fashioned as an arrow. The other section of the circuit is similar with R5 is the speed control. The LEDs on one circuit show an arrow in the direction of right and vice versa.
The circuits can be built on a single Vero board or two pieces of Vero boards for each of right and left signals. Power is taken from the lights itself appropriately.
Arrows with LEDs can be fixed on transparent acrylic sheet of suitable size. Drilling holes for LEDs should not be a problem but without a little care, acrylic sheet may break. By using an acrylic sheet, view of the rear is not lost even if the display is placed there. You may use more LED (up to 6 for red LEDs) in series for each output, but the current limiting resistor (R4, R8) must be properly trimmed. Output current should not exceed 10mA. R2, R5 presets are speed controls for LEDs.
Any one of these circuits can very well be used for window display lights, running lights and even as an electronic dice. When these LEDs are fixed concentrically in two circles, the circuits can work as hobby roulette wheel, which could be very popular in school functions. However for these circuits, the clock frequency should be suitably increased
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