Simple Light Activated 12V 2 Amp Switch

[BeeJ]

Looking for a way to build a Simple Light Activated 12VDC 2 Amp Switch.

I have a motion detector that radios to an alarm. Both are battery
operated. The alarm has a pizo speaker and LEDs that are active when
motion is sensed.

I would like a simple circuit something like a photo-transistor capable
of handling 12 VDC at 2 amp switching to run a windshield wiper pump
from a 12V gel battery. A diode across the transistor collector to
emitter to protect from motor spikes.

I could also use the the audio out as the trigger but I don't think I
can find a cheap and simple microphone controlled switch that will
handle the voltage and current.

Suggestions please.

 

[BeeJ]

It happens that BeeJ formulated :

Looking for a way to build a Simple Light Activated 12VDC 2 Amp Switch.

I have a motion detector that radios to an alarm. Both are battery operated.
The alarm has a pizo speaker and LEDs that are active when motion is sensed.

I would like a simple circuit something like a photo-transistor capable of
handling 12 VDC at 2 amp switching to run a windshield wiper pump from a 12V
gel battery. A diode across the transistor collector to emitter to protect
from motor spikes.

I could also use the the audio out as the trigger but I don't think I can
find a cheap and simple microphone controlled switch that will handle the
voltage and current.

Suggestions please.

Maybe some parts I can pick up at Fry's.

 

[hamilton]

Looking for a way to build a Simple Light Activated 12VDC 2 Amp Switch.

I have a motion detector that radios to an alarm. Both are battery
operated. The alarm has a pizo speaker and LEDs that are active when
motion is sensed.

I would like a simple circuit something like a photo-transistor capable
of handling 12 VDC at 2 amp switching to run a windshield wiper pump
from a 12V gel battery. A diode across the transistor collector to
emitter to protect from motor spikes.

I could also use the the audio out as the trigger but I don't think I
can find a cheap and simple microphone controlled switch that will
handle the voltage and current.

Suggestions please.

1. Replace LED with an opt-isolater.

Google for opt-isolater and you can find the rest.

 

[George Herold]

Looking for a way to build a Simple Light Activated 12VDC 2 Amp Switch.

I have a motion detector that radios to an alarm. Both are battery
operated.   The alarm has a pizo speaker and LEDs that are active when
motion is sensed.

I would like a simple circuit something like a photo-transistor capable
of handling 12 VDC at 2 amp switching to run a windshield wiper pump
from a 12V gel battery.  A diode across the transistor collector to
emitter to protect from motor spikes.

I could also use the the audio out as the trigger but I don't think I
can find a cheap and simple microphone controlled switch that will
handle the voltage and current.

Suggestions please.

Maybe just some sort of relay for the final switching? How many times
will it turn on and off?

George H.

 

[BeeJ]

BeeJ explained on 5/15/2013 :

Looking for a way to build a Simple Light Activated 12VDC 2 Amp Switch.

I have a motion detector that radios to an alarm. Both are battery operated.
The alarm has a pizo speaker and LEDs that are active when motion is sensed.

I would like a simple circuit something like a photo-transistor capable of
handling 12 VDC at 2 amp switching to run a windshield wiper pump from a 12V
gel battery. A diode across the transistor collector to emitter to protect
from motor spikes.

I could also use the the audio out as the trigger but I don't think I can
find a cheap and simple microphone controlled switch that will handle the
voltage and current.

Suggestions please.

The transmitter and receiver are weatherproof so I do not want to mess
with wiring.

If I had a phototransistor connected to a power transistor I could use
that to drive the pump. Looking for recommendations on parts to do
this. Or some other non-hardwired way. also I could easily swap out
the receiver for another unit easily.

 

[Edward Lee]

Looking for a way to build a Simple Light Activated 12VDC 2 Amp Switch.

I have a motion detector that radios to an alarm. Both are battery
operated.   The alarm has a pizo speaker and LEDs that are active when
motion is sensed.

I would like a simple circuit something like a photo-transistor capable
of handling 12 VDC at 2 amp switching to run a windshield wiper pump
from a 12V gel battery.  A diode across the transistor collector to
emitter to protect from motor spikes.

I could also use the the audio out as the trigger but I don't think I
can find a cheap and simple microphone controlled switch that will
handle the voltage and current.

Suggestions please.

We have plan for using this chip:

www.freescale.com/files/analog/doc/data_sheet/MPC17510.pdf

TTL/CMOS logic in

upto 15V 1.2A (3.8A peak) out

You should be able to run it for a short time at 2A.

 

[Peter Heitzer]

Can you go inside the receiver and tap some signals? You could drive a
logic-level mosfet gate with just a few volts.

Or he could put the LED of an optocoupler in series with the LED in the detector.
If the detector is operated with more than 2 AA/AAA cells, the 1.3 V drop for
the IR-LED would not harm. The transistor could drive a small relay.

 

[Jasen Betts]

Looking for a way to build a Simple Light Activated 12VDC 2 Amp Switch.

I have a motion detector that radios to an alarm. Both are battery
operated. The alarm has a pizo speaker and LEDs that are active when
motion is sensed.

I would like a simple circuit something like a photo-transistor capable
of handling 12 VDC at 2 amp switching to run a windshield wiper pump
from a 12V gel battery. A diode across the transistor collector to
emitter to protect from motor spikes.

Nah, you have to put the diode across the motor.

can you open the receiver an connect directly to the LED, the problem
gets about 20 times simpler if you can.

what's this for, controlling other peoples pets?

 

[Jasen Betts]

If I had a phototransistor connected to a power transistor I could use
that to drive the pump. Looking for recommendations on parts to do
this. Or some other non-hardwired way. also I could easily swap out
the receiver for another unit easily.

perhaps not all that easily, maybe you'd have to paint the case black to
keep stray light out etc...