First Project...help!

[prixdc]

I haven't worked much with electronics, but I have been doing some reading and hoping I can find some help here.

Here's what's going on:

I am wanting to place a remote to turn on and off a TV inside a box to be controlled by a toggle switch and an LED push button switch. I want the toggle to turn on the LED & give power to the button, and when the button is pressed the remote fires a signal.

This is what I will probably be using for the remote.

Questions:
The remote by itself is powered by two AA batteries. Would I be able to draw power from them to the toggle/LED? Would I need a separate source?

Would a push button switch even work to fire the remote? (the remote comes with a 6mm tact switch button)

As you can see, I am new at this, and I know this isn't a *serious* project, but any help is appreciated.

Thanks!

 

[waxman]

Two AA's in series give you 3 volts. Too much for most LED's. They like 2.3 volts or so. 3 volts will kill them in short order. Simplest is to put a silicon diode (or resistor) in series. A diode (or resistor) will drop .7 volts, leaving 2.3 for the LED.
Your toggle switch could simply replace the tact switch, or be in series with it, so both would have to be energized for the device to fire. No problem.
You know this "box" that you put the remote in must have a window that infrared will pass thru, right?
John

 

[prixdc]

Yes, I do know that IR needs line of sight to operate.

Would the push button be able to replace the tact switch? So flip the toggle, led comes on, push big red button, remote fires.

Any reasons this wouldn't work to have the switches in this order?

Thank you again, I know this stuff is below beginner level for everyone here...

 

[TheNthDegree]

Two AA's in series give you 3 volts. Too much for most LED's. They like 2.3 volts or so. 3 volts will kill them in short order.

Not So. Excessive forward *voltage* does not kill LEDs, excessive forward *current* does. To fully light an LED you must 1) supply it with a voltage greater than or equal to it's rated forward voltage drop (Vf) and 2) insert a resistor in series with it to limit it's forward current (If) to a safe value.

The Vf of LEDs varies but is generally related to the emitted color of the LED. For example, the following are good guestimates for the Vf for common LEDs:

Infrared: 1.2 to 1.8 V
Red, Yellow, Amber: 1.8 to 2.4 V
Green, Blue, Violet, White: 3.0 to 3.4 V

Again, these are just general guidelines, be sure to check the datasheet for your LED(s) to get the correct Vf and If values...

Hope that helps,
-Nick

 

[TheNthDegree]

Questions:
The remote by itself is powered by two AA batteries. Would I be able to draw power from them to the toggle/LED? Would I need a separate source?
Would a push button switch even work to fire the remote? (the remote comes with a 6mm tact switch button)

Yes, you can use the remote's batteries for the LED... see above. The easiest way to add you own "external" switch to the remote would likely be to open it up and solder wires to the two connectors/ Printed Circuit Board (PCB) pads where the existing switch is installed (removing the tact switch will make this easier), and then connecting your switches up to those wires...

-Nick

 

[waxman]

Oops. My bad. I should have stated, "3 volts will cause excessive current to flow through the LED causing failure".
Thanks for the clarification, TheNthdegree!