Installing an LED

[Gus Chiggins]

Hello all. I was directed here from the alt.guitar.effects group. What I
would like to do is wire an LED to a Roland FS-1 foot switch pedal. The
pedal switches between two channels on my guitar amp and I would like to put
an LED on it so I know when it's on a specific channel. Thanks in advance
for any help.

Gus

 

[colin]

"Gus Chiggins" <guschiggins@nospam.com> wrote in message
news:924fe$457993e4$d8447881$5399@FUSE.NET...

Hello all. I was directed here from the alt.guitar.effects group. What I
would like to do is wire an LED to a Roland FS-1 foot switch pedal. The
pedal switches between two channels on my guitar amp and I would like to
put
an LED on it so I know when it's on a specific channel. Thanks in advance
for any help.

Might be tricky as I doubt there are any spare contacts on the switch,
although I dont know about footpedals,
using the switch to turn on a relay (to switch the channels) and the led as
well might be an option.

Colin =^.^=

 

[Lostgallifreyan]

"colin" <no.spam.for.me@ntlworld.com> wrote in
news:sGgeh.2753$493.940@newsfe4-gui.ntli.net:

"Gus Chiggins" <guschiggins@nospam.com> wrote in message
news:924fe$457993e4$d8447881$5399@FUSE.NET...
Hello all. I was directed here from the alt.guitar.effects group.
What I would like to do is wire an LED to a Roland FS-1 foot switch
pedal. The pedal switches between two channels on my guitar amp and
I would like to
put
an LED on it so I know when it's on a specific channel. Thanks in
advance for any help.

Might be tricky as I doubt there are any spare contacts on the switch,
although I dont know about footpedals,
using the switch to turn on a relay (to switch the channels) and the
led as well might be an option.

Colin =^.^=

If there are no switches spare it might be easier to build something than
to reverse engineer to find a way. If it's just a passive switch, reverse
engineering won;t show you anything you can use anyway.

In which case, look at op-amp circuits in any basic guide on their use. Try
a CA3140 as that uses a single rail supply of 9V with no trouble. Build a
high-gain amp with no feedback, and a diode in series with the positive
input, ground the negative (inverting) input, and put a capacitor (try
10ľF) on the output. Connect the LED to that output via a series resistor.
This should light the LED when there is a signal of greater than 0.6 volts
present. If you want it more sensitive, you can try a germanium diode.

 

[ehsjr]

Gus Chiggins wrote:

Hello all. I was directed here from the alt.guitar.effects group. What I
would like to do is wire an LED to a Roland FS-1 foot switch pedal. The
pedal switches between two channels on my guitar amp and I would like to put
an LED on it so I know when it's on a specific channel. Thanks in advance
for any help.

Gus

As I understand it, the Roland FS-1 is an on/off switch -
that is, press it once and it is on and stays on until
you press it again. The being the case, it is easiest
to use a relay and a wall wart power supply to do what
you want. Here's a diagram:

+----------[1K]-------+ +------A
| | |
| ----- | |
| |Relay| +->| <| ->| <|
| ----- | | |
------ | / | | | | |
|Wall +|---+---o o---+ | [LED1] | +---B
|Wart | FS-1 |k | | |
| | [D1] | | [LED2]
|12V | | | | |
|DC -|-------------+---+----+-----+
------

Use a DPDT 12 volt relay. (You could use a lower voltage
relay with a suitable series dropping resistor.) One set
of contacts is used to select which LED is lit - the other
is connected to the amp to select the channel to be used.
If foot switch (FS-1) is off, the relay is not energized, and
LED1 is lit through the 1K current limiting resistor, and
the normally closed point on one relay contact set. (The
other relay contact set normally open and common points are
connected to the amp at points A and B in the diagram.)

When you close the Roland switch, the relay energizes, and
the relay contacts transfer, lighting LED2, extinguishing
LED1 and selecting the other channel in the amp. A second
press of the foot switch opens it, and the relay de-energizes.
Diode D1 ( with the non-banded end wired to - ) prevents the
inductive spike generated when the relay is de-energized from
getting into the wall wart power supply.

Ed