RJ said:
Anyone have any info/schematic for automotive (12V) sequential flasher
circuit. Looking for something that will run a string of bulbs left to
right, right to left, and center out. 55W halogen bulbs. Also known as a
"Traffic Advisor" and is mounted on the rear of a cruiser. Thanks any and
all.............
Dick J
Gahanna Police Dept, Ohio
Your call - but if it's for your job, I would think a commercial
unit would be what you want. But if you enjoy experimenting, you
might like the circuit described and diagramed below.
There are diagrams below the text.
4 decade counters, 9 bulbs: (can be more than 9 bulbs
with additional decade counters)
The "master_counter" 1 one counts 0 to 2 and resets at 3, so it
has 3 active outputs: 0, then 1, then 2. All decade
counters will have only 1 output active at any given time.
Bulbs will be wired to drivers, and the drivers will be
connected to decade outputs 1 through 9 through diodes.
The master_counter will sequentialy enable counter0,
counter1 and counter2 when master_counter_0, 1 and 2
go active. The master_counter will be incremented
when counter0 or 1 reaches 9, or when counter2 reaches 5
Counter0 will sequentially light bulbs
1 2 3 4 5 6 7 8 9 yielding this ==> direction
Counter1 will sequentially light bulbs
9 8 7 6 5 4 3 2 1 yielding this <== direction
counter2 will light first bulb 5, then in pairs:
6&4, 7&3, 2&8, 1&9 yielding this <= => direction
When counter2 increments to 5, it will reset itself and increment
the mastercounter
A typical decade counter circuit is shown here:
http://www.doctronics.co.uk/4017.htm
Your drivers can be n channel mosfets, wired source to
ground, drain to bulb, bulb to plus. The gates of
each mosfet will connect to 3 diodes, with the banded
end of the diode connected to the gate and the other end
connected to the 0, or 1 or 2 ... or 8 line of the
decade counter.
---------------
| mastercounter | DR = driver, detail shown below
---------------
0 1 2
| | |
--- | |
| C |0-------->|---------------------Dr1---Bulb1--+--- +V
| o |1-------->|---------------------+ |
| u |2-------->|-------------------+ | |
| n |3-------->|-----------------+ | Dr2---Bulb2--+
| t |4-------->|---------------+ | +-+ |
| e |5-------->|-------------+ | | | |
| r |6-------->|-----------+ | | | Dr3---Bulb3--+
| |7-------->|---------+ | | | +---+ |
| 1 |8-------->|-------+ | | | | | |
--- | | | | | | | Dr4---Bulb4--+
| | | | | | | +-----+ |
+---+ | | | | | | | |
| | | | | | | Dr5---Bulb5--+
| | | | | | +-------+ |
| | | | | | | |
| | | | | | Dr6---Bulb6--+
| | | | | +---------+ |
| | | | | | |
| | | | | Dr7---Bulb7--+
| | | | +-+---------+ |
| | | | | | |
| | | | | Dr8---Bulb8--+
| | | +-+-----------+ |
| | | | | | |
| --- | | | Dr9---Bulb9--+
| | C |0-------->|---+ |
| | o |1-------->|-----+
| | u |2-------->|--- To Dr7
| | n |3-------->|--- To Dr6
| | t |4-------->|--- To Dr5
| | e |5-------->|--- To Dr4
| | r |6-------->|--- To Dr3
| | |7-------->|--- To Dr2
| | 2 |8-------->|--- To Dr1
| --- |
| 9 |
| | |
+---------+ ---
| | C |0-+->|--- To Dr5
| | |
| | o |1-+->|--- To Dr6
| | | +->|--- To Dr4
| | |
| | u |2-+->|--- To Dr7
| | | +->|--- To Dr3
| | |
| | n |3-+->|--- To Dr8
| | | +->|--- To Dr2
| | |
| | t |4-+->|--- To Dr9
| | | +->|--- To Dr1
| | |
| | e |5---+
| | r |6 |
| | 0 |7 |
| | |8 |
| --- |
| |
+---------------------+
Driver detail:
V+
|
Bulb
|
||---+ D
| ||
G ----- ||---+ S
|
Gnd
Counter enabling via the master counter & power on reset:
Counter0 Counter1 Counter2
Enable Enable Enable
Pin13 Pin13 Pin13
| | |
+-+ +-+ +-+
-------- | | | | | |
|Master |0-+->|---------------------+ | | |
|Counter | +->|-----------------------------+ |
| | | | | | |
| |1-+->|-----------+ | | |
| | +->|-------------------------------+
| | | | |
| |2-+->|-------------+ |
| | +->|-----------------------+
| |
| |3---+ +--->|--- To pin 15 Counter0
-------- | +--->|--- To pin 15 Counter1
Reset | +--->|--- To pin 15 Counter2
Pin15 | |
| | | 10 uF
+---------+---|<---+---||------- +V
|
[15K]
|
Gnd
Clocking:
The clock shown at
http://www.doctronics.co.uk/4017.htm
will connect to Counters 0, 1 and 2.
It will not connect to the mastercounter.
The mastercounter clock pin - pin 14 - will connect
to 3 diodes (non-banded end). The other end of the diodes
will connect to output 9 (pin 11) of counter0 and counter1,
and to outpiut 5 (pin 1) of counter2.
Ed
