AWGB Woodturning Forum
General Category => General Discussion => Topic started by: Lazurus on March 13, 2018, 11:03:46 AM
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I am making some stands which need to incorporate a vertical light source to illuminate the current orb obsession, I have tried small LED torches which whilst work fine mean I have to make the stand big enough to incorporate the torch itself some 70 - 80mm tall with a minimum 20mm bore to set the torch into.
Really only a single bright LED would suffice, so can someone advice what and how to wire and power a simple LED circuit or recommend a simple strip of LEDs to use.
Ta
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Hi Lazurus -- I depends on your power source, the LED in the picture is usually a 3.6v device so if you had a small 12v battery (the type used in burglar alarms) you could run 4 of them in series. If it's a 12v device then use the same battery but run them in parallel, the battery will last for ages. Julian
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most household led lights run from 240 with a small transformer unit to drop it to 12v. You can run a number of small ones from these. I put some in a camper recently with no problems. (Wait for the H & S warnings)
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https://www.smallscalelights.co.uk/product/3_volt_coin_cell_battery_holder_and_switch
The perfect shop.
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I don't think the battery would last very long on this one Lazurus.
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According to the interweb, nominal capacity of a CR2032 is 220mAh. A 3V LED light will consume anywhere between 20mA and well over 500mA. So at the lower end of that scale you get about 11 hours of operation, whereas at the higher end your little coin battery is flat in under half an hour.
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Hmmmmm, nothing is simple is it.... I have emailed the gent with what I am trying to achieve although the button battery would be ideal as easy to secrete within various shaped display stands I guess a couple of AAA batteries are not out of the way and still easy to conceal. I will see what he suggests.
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If you are going to run it off batteries then why not strip a torch down and use the head and wiring only. Easy enough to make a battery box up and all the nessesary wiring done for you
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Two AA batteries would last at least 20 times longer than the button cell so perhaps those would be a better power source?
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The problem is I need a small solution as I wish to reduce the size of the plinths I am currently using, on a small orb they look clumsy beneath.
The company got back to me very quickly, very helpful and are looking at a bespoke solution, on a single LED the button cell gives around 11 hours continuous running, more than enough. I wish to recess the LED under the or, feed the small wires to the underside of the plinth then recess to fit the battery and small switch.
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Lazurus,
Here is a link to a LED circuit design site, actually it's all things LED but certainly far more than you would need to know.
http://led.linear1.org/led.wiz (http://led.linear1.org/led.wiz)
If you put in the LED details and voltage source (Battery or powersupply) it will do the rest for you.
Incidentally, when the Car Boot season comes around, old 5V mobile phone charges are great for running small LED Circuits.
My background is Electronics, if you are not so sure what the LED characteristics wanted in the LED Web site are, you can get the Datasheet for all LEDs quite simply off the web.
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Incidentally, don't feel constrained to stick to one colour, you can get Rainbow LEDs that cycle through a sequence of colours.
https://www.kitronik.co.uk/3527-colour-changing-5mm-diffused-led-750mcd.html (https://www.kitronik.co.uk/3527-colour-changing-5mm-diffused-led-750mcd.html)
The datasheet fro this LED is given under the resources heading, below the picture.
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Just something to consider, an idea I'll be trying myself at some stage... conductive paint.
What about insetting a 3mm led into the wood itself before you add the resin?
Drill 2 very small diameter (1/2mm) holes through the wood base to the bottom of the LED pins. Set the LED in place, then inject contact paint through the holes with a syringe, allow it to set, making contact with the bottom of the 2 LED pins. That way, you have an electrical contact running through the wood to the LED. Test the connection, then add the resin and turn, finish the piece.
Then, if you set 2 tiny contact plates (+ve and -ve) into your base (foil etc?), it will complete the circuit when your contact paint in the piece touches the contact plates, and the light will come on. The light will go off when you pick up the piece. You can put the resistor in the base, soldered to the positive connection, between the battery and the contact plate.
The only thing to make sure of is that when you wax/polish/lacquer to finish, you don't get any on the contact paint at the bottom of the piece, or it will create a barrier to the circuit and break the contact.
Mad, quite probably.
Adventurous/creative, definately.
(see https://www.kitronik.co.uk/4804-bare-conductive-paint-10ml-pen.html)
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Just something to consider, an idea I'll be trying myself at some stage... conductive paint.
What about insetting a 3mm led into the wood itself before you add the resin?
Drill 2 very small diameter (1/2mm) holes through the wood base to the bottom of the LED pins. Set the LED in place, then inject contact paint through the holes with a syringe, allow it to set, making contact with the bottom of the 2 LED pins. That way, you have an electrical contact running through the wood to the LED. Test the connection, then add the resin and turn, finish the piece.
Then, if you set 2 tiny contact plates (+ve and -ve) into your base (foil etc?), it will complete the circuit when your contact paint in the piece touches the contact plates, and the light will come on. The light will go off when you pick up the piece. You can put the resistor in the base, soldered to the positive connection, between the battery and the contact plate.
The only thing to make sure of is that when you wax/polish/lacquer to finish, you don't get any on the contact paint at the bottom of the piece, or it will create a barrier to the circuit and break the contact.
Mad, quite probably.
Adventurous/creative, definately.
(see https://www.kitronik.co.uk/4804-bare-conductive-paint-10ml-pen.html)
I like this idea, will ponder and speculate on it, my thanks.
S.