P
pimpom
- Jan 1, 1970
- 0
Continuing the saga of my drag racing Christmas lights project, I
have another question.
Since the race is to be held in an abandoned air strip an hour's
drive out of town, mains power is probably not reliable there,
and I don't want to depend on a portable generator either. So I
thought I'd design everything to use batteries for this event - a
12V truck battery for the lights.
LEDs would be efficient but I won't be able to get readymade
LED-array lamps in time - another restriction due to my location.
And I want to avoid the addititonal workload of manually
assembling 14 lamps of several dozen LEDs each and having to
improvise reliable mechanical holders for them. So I thought I'd
use incandescent automobile light bulbs for the lights.
I've finished a tentative design of the entire timing, sensing
and control unit, using MOSFETs to drive the lamps (Relays would
introduce additional delays when times will be measured in small
fractions of a second. Unless a better idea comes up, I'll just
have to accept the turn-on delay of the incandescent lamps as
unavoidable).
The actual wire lengths from the control unit to the lamps will
be 2-3 dozen feet. At first, I thought I'd avoid having to run
more than a dozen thick gauge wires over that distance by placing
the MOSFETs near the lamps and use a cable of thinner wires to
send the gate drives. But I've had second thoughts and this is
what my question is about: Will cable capacitance, inductance and
cross-coupling pose problems with that scheme? Thanks in advance.
have another question.
Since the race is to be held in an abandoned air strip an hour's
drive out of town, mains power is probably not reliable there,
and I don't want to depend on a portable generator either. So I
thought I'd design everything to use batteries for this event - a
12V truck battery for the lights.
LEDs would be efficient but I won't be able to get readymade
LED-array lamps in time - another restriction due to my location.
And I want to avoid the addititonal workload of manually
assembling 14 lamps of several dozen LEDs each and having to
improvise reliable mechanical holders for them. So I thought I'd
use incandescent automobile light bulbs for the lights.
I've finished a tentative design of the entire timing, sensing
and control unit, using MOSFETs to drive the lamps (Relays would
introduce additional delays when times will be measured in small
fractions of a second. Unless a better idea comes up, I'll just
have to accept the turn-on delay of the incandescent lamps as
unavoidable).
The actual wire lengths from the control unit to the lamps will
be 2-3 dozen feet. At first, I thought I'd avoid having to run
more than a dozen thick gauge wires over that distance by placing
the MOSFETs near the lamps and use a cable of thinner wires to
send the gate drives. But I've had second thoughts and this is
what my question is about: Will cable capacitance, inductance and
cross-coupling pose problems with that scheme? Thanks in advance.