Back story: I am a magician who decided to make an electronic candle because the fire department won't give me a permit to perform my candles act. What I need doesn't yet exist. Even the Fantasio, the man who came popularized the candles doesn't have what I need. I've spoken with him already and he has great ideas, but I need more. Here is what I need.

The Project I need an orange LED to light up when I bring a magnet close to it. Then I need it to turn off with a breaker switch, like a mercury switch. And most importantly, I need it to stay off until I turn it on again with a magnet, regardless is the mercury switch is making a connection or not. And it all has to fit in a tube about the size of a chapstick tube.

Basically, I want to recreate the look and feel of lighting a long tapered candle. The magnet is on the Lighter, which will also have an LED to simulate a flame. When I bring this to the tip of the tapered candle, the LED with light up with no visible switches, like magic. When I tilt the candle far enough, the light will turn off. This is necessary to not give a tell tale where the candle is when I disappear it.

What I have done so far I have used a hall latch switch which works great to turn the LED on with a magnet. The LED turns off when the mercury or tilt switch is tilted. Unfortunately, the LED turns right back on when the mercury switch is connecting again. It is as if the hall effect switch remembers where it was last positioned with the magnet.

I need something that will work and unfortunately, I just don't know enough about electronics yet to find a better solution. Any help would be appreciated.

 

You could try a 555 as a flip flop (no RC timing). Hook the hall switch to ground pin 2 to set it (LED on) and the mercury switch to reset it. See Bill Marsden's 555 blog here and the ebook for all you need. The BiStable Multivibrator (flip/flop) 555 circuit is described in detail here although its set up for toggling.

You could also hone your programming chops with a cheap 8 pin PIC for even more effects.

Off to the Magic Castle!

 

If you are using one of the Honeywell SS400 etc latch sensors, then as long as the power is on the proximity latch it will stay engaged until the opposing pole unlatches it.
But if you remove total power to it via the merc. sw, it reverts back to it original state.
It sounds as if the mercury sw is made initially anyway?
Max.

 

@Max- I am not using a Honeywell. I just order off ebay from China. Even if I unplug the power, when I reconnect the battery, the hall switch will stay on. And even weirder, If I have the hall switch on the off position, then unplug the battery, then plug it back, sometimes the light with turn on. And it seems to be random.

@John- Thanks, I will check that out. Are you a member of the Magic Castle? I up there all the time.

 

@Max- I am not using a Honeywell. I just order off ebay from China. Even if I unplug the power, when I reconnect the battery, the hall switch will stay on.

.

It sounds like you have the wrong sensor?
http://www.digikey.ca/product-detail/en/SS461A/480-2003-ND/701358
Max.

 

@John- Thanks, I will check that out. Are you a member of the Magic Castle? I up there all the time.

No but a buddy of mine and I used to do enough magic (1980's) to impress the bar chicks and got invited there a couple of times. Incredible talent on display.

Let us know how your project comes along.

 

Damn.. why did I read this post.. Now I know its all just a trick..
Say hi to NPH for me

On to the next post.. Hopefully its not about the Tooth Fairy being a lie too.

 

Do you have a flickering orange candle LED? What battery V do you have.? R-S SN 276-1646 is another choice for Hall sensor. A small SCR like 2N5060 can be used to latch sensor output untill reset by Hg SW. I also have a tilt SW about the size of a pea available.

 

It Works! Max, you were right all along about hall switches. They don't keep "memory". I just had the whole thing wired up wrong. Thank you, thank you, thank you Max!!! But I will look into 555 timers because I am really getting into this stuff.

 

@Bernard. No, I don't have a flickering orange LED. After much though and trial and error, I decided against them because the flickering yellow LEDs looked cheesy to me. The superbrite orange LEDs with a flame tip cap look way better and more realistic, believe it or not. I am pulling the flame tips off electronic tea lights which are very inexpensive.

 

Oh, I will be using 4.5 volts with a 150Ω resistor. The power source comes from these things called Balloon Lights. The are about the size of a bullet and you can get them at Party City or Amazon.

I am going to take out the white LED light and solder the contact points with wire. The circuit will be set on a narrow piece of perfboard, about 4 dots wide by 13 dots long. (I don't know all the terminology yet.)

I've done a lot of thinking on this project. And now the hard part is over.

 

As a tip, I've seen normal LEDs used, with a blob of hot glue teased into a flame shape. Increases your options as you don't need the LED tea lights.

 

I may experiment with that. Thanks DJ.

 

You can use a tea light to drive a bright orange LED, if you do not have a flickering orange LED.