Lights for scale boats

J

JSchermeis

Guest
Help! I build radio controlled scale ships and boats as a hobby and need a
circuit to operate the lights. Depending on the model, the main power is
between 6 & 12v dc. I'm using 1.5v, 30mA bulbs, and need from 5 to 15 lights
per model. The lights should operate at 1.3v for longer life and authentic
appearance. I don't read schematics that well and have even less of a clue how
to use it to make the finished circuit. But I could use about 10 of these in
my projects. Any ideas?
John
 
Hi,

Help! I build radio controlled scale ships and boats as a hobby and need a
circuit to operate the lights. Depending on the model, the main power is
between 6 & 12v dc. I'm using 1.5v, 30mA bulbs, and need from 5 to 15 lights
per model. The lights should operate at 1.3v for longer life and authentic
appearance. I don't read schematics that well and have even less of a clue how
to use it to make the finished circuit. But I could use about 10 of these in
my projects. Any ideas?
Click to expand...

Why not try something like this? (View in Courier)!

-----
O ----|78L05|-----------------------
----- | | |
| (x) (x) (x)
| | | |
| (x) (x) (x)
7-12V DC | | | |
| (x) (x) (x)
| | | |
| (x) (x) (x)
| | | |
O-----------------------------------

The x's are lamps and the 78L05 is a small 5V regulator that should be
available from any electronics hobby shop. This will give you 1.25V per lamp and
will take up any slack should you use a variety of supply voltages. You could use
the 1A capacity 7805 instead without a heatsink as you will be drawing less than
100mA. In fact, if you have the room, I would use the 7805 anyway.


Cheers - Joe
 
Yes, I was about to suggest the same thing, except without the
regulator. On a battery-powered boat, I'd think that you don't
want to throw away any watts (which is what a regulator does) -
just put the right number of bulbs in series for either a 6V
or 12V system. I certainly wouldn't put in a universal light
string, because once you've picked a battery for a given
boat, it probably won't change.

I'd also go for more than 1.3 as a target bulb voltage - it's
amazing how much difference in light output there is for a
very small change in voltage near its operating area. Say,
1.4 ~ 1.45V. The important part, of course, is the current
flow. John presumably knows to use matched bulbs, of course. :)

The simplest thing would be to put 4 or 5 in series for a 6V
system, and see which looks best, and 8 or 9 in series for a
12V system. If you really want to fine-tune it, you could
interpose some smaller resistance in series - even something
like a car bulb - it wouldn't light, but it'd drop the voltage
a little, so the bulbs will last longer.

Good Luck!
Rich

Joe McElvenney wrote:
Hi,


Help! I build radio controlled scale ships and boats as a hobby and need a
circuit to operate the lights. Depending on the model, the main power is
between 6 & 12v dc. I'm using 1.5v, 30mA bulbs, and need from 5 to 15 lights
per model. The lights should operate at 1.3v for longer life and authentic
appearance. I don't read schematics that well and have even less of a clue how
to use it to make the finished circuit. But I could use about 10 of these in
my projects. Any ideas?



Why not try something like this? (View in Courier)!

-----
O ----|78L05|-----------------------
----- | | |
| (x) (x) (x)
| | | |
| (x) (x) (x)
7-12V DC | | | |
| (x) (x) (x)
| | | |
| (x) (x) (x)
| | | |
O-----------------------------------

The x's are lamps and the 78L05 is a small 5V regulator that should be
available from any electronics hobby shop. This will give you 1.25V per lamp and
will take up any slack should you use a variety of supply voltages. You could use
the 1A capacity 7805 instead without a heatsink as you will be drawing less than
100mA. In fact, if you have the room, I would use the 7805 anyway.


Cheers - Joe
Click to expand...
 
In article <20031024000845.11333.00000058@mb-m15.aol.com>,
jschermeis@aol.com mentioned...
Help! I build radio controlled scale ships and boats as a hobby and need a
circuit to operate the lights. Depending on the model, the main power is
between 6 & 12v dc. I'm using 1.5v, 30mA bulbs, and need from 5 to 15 lights
per model. The lights should operate at 1.3v for longer life and authentic
appearance. I don't read schematics that well and have even less of a clue how
to use it to make the finished circuit. But I could use about 10 of these in
my projects. Any ideas?
John
Click to expand...
An LM317 will give you 1.2V with the adj pin grounded, and if you use
the regular 3 resistor circuit, any voltage above that up to its
maximum.


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