Hi All,
I'm trying to figure out a retrofit taillight "chase" sequencer for an older car. Instead of one brake lamp on each side there will be three. I want to use the original wiring to the rear of the car and add a "black box" in the trunk. I intend to run a separate number 8 or so wire from the battery for power so the current doesn't have to go through the old wiring. Three lights on each side for turn signals that chase each other.
Logic is this:
1. If turn signal is on there is a pulse from the switch that triggers the chase circuit.This is the same wire that is on steady for brakes. This can be a 4017 driven by a 555.
2. If the brake pedal is pushed all three lamps come on, they do not sequence. Most of the circuits I have seen cause the lamps to sequence when the line goes high.
3. The turn signal overrides the brakes. In other words, if the brake pedal is pushed while signaling a turn one side sequences and the other has all three lamps on.
What should I use to drive the lamps? The 4017 has very little current capability. Do I drive a transistor that in turn drives a relay or can a mosfet be used for fewer parts count? Can the 4017 drive a power mosfet directly?
There are a number of circuits on the 'Net but I haven't seen one that uses only the two wires (left and right brake lights) and the original stock wiring. I don't mind running a power wire from the battery but don't want to get under the dash to change the car's stock setup.
Thanks,
BiggyR
I'm trying to figure out a retrofit taillight "chase" sequencer for an older car. Instead of one brake lamp on each side there will be three. I want to use the original wiring to the rear of the car and add a "black box" in the trunk. I intend to run a separate number 8 or so wire from the battery for power so the current doesn't have to go through the old wiring. Three lights on each side for turn signals that chase each other.
Logic is this:
1. If turn signal is on there is a pulse from the switch that triggers the chase circuit.This is the same wire that is on steady for brakes. This can be a 4017 driven by a 555.
2. If the brake pedal is pushed all three lamps come on, they do not sequence. Most of the circuits I have seen cause the lamps to sequence when the line goes high.
3. The turn signal overrides the brakes. In other words, if the brake pedal is pushed while signaling a turn one side sequences and the other has all three lamps on.
What should I use to drive the lamps? The 4017 has very little current capability. Do I drive a transistor that in turn drives a relay or can a mosfet be used for fewer parts count? Can the 4017 drive a power mosfet directly?
There are a number of circuits on the 'Net but I haven't seen one that uses only the two wires (left and right brake lights) and the original stock wiring. I don't mind running a power wire from the battery but don't want to get under the dash to change the car's stock setup.
Thanks,
BiggyR