Component needed?

Question

I have built a very simple circuit that attaches to a horseshoe pitching glove. It consists of a 9v battery, red led and turns on when two bare wires close the circuit when the leads, one on the finger and one on the thumb, cause the led to go off when the shoe is released. I would like to somehow reverse when the led goes on and off. I would like to add a component(s) that causes the led to go ON when continuity is broken, instead of going OFF. Can anyone recommend a simple design. I am assuming that I will also need a small ON/OFF switch to turn off the LED when not in use. Thanks for any help. Please be specific about any component and how to wire it.

Again, thanks...

Tim Wescott · Accepted Answer

Google for "inverter".  Find a schematic, follow the instructions.-- Tim WescottWescott Design ServicesDo you need to implement control loops in software?"Applied Control Theory for Embedded Systems" gives you just what it says.See details at

Photon713 · Answer

Thank you Tim...will do..appreciate it.-- __________lvMMMCCIX

John Larkin · Answer

What, no resistor? That's runing the risk of frying the LED.

Do this:

The glove contacts short out the LED, and turn it off.

The resistor could be a cheapie RatShack 1/4 watt resistor, 270 ohms to 1000 maybe. Less ohms = brighter LED = shorter battery life.

John

Photon713 · Answer

Thanks John...that looks simple enough...just what I need.Couldn't find anything about an inverter that did anything otherthan convert DC to AC.  Appreciate the help...-- __________lvMMMCCIX

DJ Delorie · Answer

Transistor?  10k resistor pulls base to collector side of battery,contacts connect base to emitter.

Phil Allison · Answer

"Tim Wescott...** So the OP will wind up building a switching PSU circuit  -  right ?  Do be careful about ambiguity in terminology.......   Phil

Den · Answer

Without adding more components:Battery +ve -----Resistor------ + LED - ------------------ Battery -ve                                          |          |                                          |          |                                          |__switch__|When switch closes led will be short circuited and will go off.The down side of doing it this way is that the battery will always have a load of ~10mA on it, a high efficiency LED could extend the battery life as they need a lower current. The up side is its simple - don't forget to disconnect battery when not in use.In sunlight outdoors a clear (plastic lens) LED may be better than a tinted one as you will definitely know its on if you can see the red colour.

Tim Wescott · Answer

Yea, yea -- I seem to have suffered from inadequate imagination.If done right it could be used to light up _lots_ of LEDs, though.-- Tim WescottWescott Design ServicesDo you need to implement control loops in software?"Applied Control Theory for Embedded Systems" gives you just what it says.See details at

Stephen D. Barnes · Answer

I think the intention was "logic inverter"! Google for SN74LS04 hex inverter ICRegards,Steve

Jamie · Answer

Look up a 555 timer circuit and use the RESET line to hold theLED on. the timer will be configed as Astable.//"

Component needed?

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