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Can anyone help me circuit a Tricorder?


New Member
Hi there!

I have 12x 3mm LED's:

- 6x flashing
- 6x static

To this I have a standard slide switch and cell battery holder.

My issue is this: how do I link these 14 components to one another and ensure the flashing LEDs stay flashing and the static, static?

I believe that a 6V battery will power all 12 LED's but this I cannot be certain of as I have only got so far with linking them together. On the face of it, it sounds simple, but (in my ignorance and lack of experience) I have found it not to be so.

If anyone can help me, I have been trying on and off for months!


Well-Known Member
Most Helpful Member
What colour are the LEDs? If they are red / green they will be about 2 - 2.5V each so you can run 2 with a suitable resistor. If they are blue / white, they will about 3 V each, so it's difficult to control the current if you have more than one with a resistor.

Once you've got 1 or 2 LEDs and a suitable resistor, you need 6 or 3 repeats of the circuit to get to 6 static LEDs

You then have the whole lot again for the flashing ones, and you have a suitable switching device in series with the flashing ones to turn them on and off to make them flash.


New Member
Hey Diver300!

Thanks for taking the time to reply :)

I have 4x flashing blue, 2x flashing red, 2x static yellow and 2x static pink if this makes a difference to your proposal?


Well-Known Member
Most Helpful Member
You need to know the specification of the flashing LEDs. They are normally designed to work with a particular supply voltage, e.g. 5V or 12V. One rated for 12V would not work with a 6V supply. One rated for 5V would probably die quickly with a 6V supply.


Well-Known Member
Most Helpful Member
You probably would want a resistor per LED, Typical If is 10-20 mA, Typical Vf is 2.1 but varies by color and batch. Intensity variations are related to Vf. You can adjust the intensity by changing the resistor and/or the supply voltage. LED's are typically currrent regulated

Resistors are calculated by R<=(6-2.1)/10e-3; fill in your values; (1/4 to 1/2 W would be fine)

Your flashing LEDs probably have a supply range.


If it could all run in 3 volts, It may be good. There are toy Tricorders as well that you could rip the guyts out of

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