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I'm looking to do a quick, cheap, DIY LED project. But not sure what I actually need to shop for.

I'm making this drinking game similar to Plinko from the game show The Price is Right. I would like to add battery powered LEDs to the inside if it's frame.

Here's some specs/ideas on what I'm looking for:

  • These are for visual effects mostly, with some illumination at night. So, not a lot of voltage. Maybe 3mm?
  • The frame (inside dimensions) will be about 18x30 inches. I'm thinking maybe 2 LEDs shining down from the top, and 3 on each side.
  • I want them to blink slowly (like the rate a christmas tree light does). But each one should blink on it's own, not all of them at once.
  • Looking for white or rotating color. Exact temp isn't important.
  • I'll be using a plastic battery case to power it. Either D batteries or AA. Case isn't bought yet, so I can still get one that holds a different number.
  • I'd like for 1 set of batteries to last at least 12 hours.
  • I need it to be easy to wire up. I say this because I've seen some that look mounted on a tiny disc that needs special contacts. Some soldering is OK, but the soldering gun I own isn't very precise. These will be mounted in the wooden frame (prob through drilled holes).
  • Will I need resistor(s) as well?

I hope that answers any questions that's needed. Can you lead me to know what I'm actually looking for? Thank you very much.

P.S. In case you need a better idea of what I'm making, here's a rough image. Little circles are pegs. Orange ball is dropped at the top, bounces down the pegs, & lands in one of the slots at the bottom.

enter image description here

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  • \$\begingroup\$ 8 LEDs x 3 colours or single colour ? 1 at time in rotation or random? Rotating colours or fixed? \$\endgroup\$ – Sunnyskyguy EE75 Jul 17 '18 at 0:41
  • \$\begingroup\$ My xmas tree lights don't blink at all, so I don't know what you mean by that reference. How many watts is your soldering gun? Can you assemble a PCB? \$\endgroup\$ – Elliot Alderson Jul 17 '18 at 0:50
  • \$\begingroup\$ Tony: Each LED blinking with no reference to the others. So they may blink at diff rates. Don't know what you mean by fixed. I've seen LEDs for sale that rotate through a few colors. I don't care if it's a random color or set sequence. \$\endgroup\$ – Tom Collins Jul 17 '18 at 1:00
  • \$\begingroup\$ Elliot: I think my soldering gun is 90 watts. Bought it Home Depot. The blinking rate should be maybe .5 - 1 hertz. PCB? Don't know what that is. Something circuit board? \$\endgroup\$ – Tom Collins Jul 17 '18 at 1:02
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The inexpensive simple solution is to use blinking RGB LEDs.

Something like this RGB Full Multi color Flashing LEDs

No external components required for blinking or color selection. Some of these blinking RGB LEDs randomize the color for each blink, not sure about these. There are more links to others on this page.



Batteries

You cannot just look at the nominal voltage of a battery to power LEDs. The cuttoff voltage (i.e. fully discharged) is just as important.

A Li-ion 18650 cells are generally the preferred battery for LEDs. The voltage is close to LED Vf and the discharge curve is flat keeping intensity somewhat constant.

AA batteries operate from 1.5v to 0.8V. The discharge curve is steep. This means the LED will get much dimmer as the battery discharges.

enter image description here
Source: ENERGIZER E91 AA Datasheet


Li-ion 18650 batteries operate from 4.0v to 3.0V. The discharge curve is flat. This means the LED will not get as dim as the battery discharges.

enter image description here
Panasonic Li-ion NCR18650PF Datasheet



NiMH operate from 1.3v to 1.2V. NiMH has a very flat discharge curve better than all others. NiMH has less capacity than Li-ion 18650 and may not last as many hours.

enter image description here
Source: NICKEL METAL HYDRIDE Panasonic HHR120AA



There is more detail in this answer: How to measure Alkaline battery lifetime/capacity in practice LED circuit?

Here is the characteristics of common batteries
type=>full charge-discharged, volts difference (lower is better), % difference over full charge (lower is better), typical capacity (higher is better)

9V Alkaline => 9V-5V,     4V,   44%,  300 mAH  
CR123A      => 3V-2V,     1V,   33%, 1500 mAH
AA Alkaline => 1.2V-0.8V, 0.4V, 33%, 2800 mAH
Li-ion      => 3.6V-3.2V  0.4V, 11%, 3000 mAH
NiMH        => 1.3V-1.2V, 0.1V,  7%, 2300 mAH

If using current limiting resistors use the mid-point voltage of the discharge curve to calculate the value.

Compare the discharge curves
1.2V NiMH Panasonic NICKEL METAL HYDRIDE HANDBOOK
18650 LI-ion battery Panasonic Li-ion NCR18650PF
9V alkaline Energizer 9V Alkaline Battery
1.2V alkaline Energizer AA Alkaline
3V (not recommended) Energizer CR123A

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  • \$\begingroup\$ Never got time to install the LEDs. Maybe next year I'll add them to the game. Thanks. \$\endgroup\$ – Tom Collins Aug 7 '18 at 0:37
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You should get a pencil soldering iron 25~35W 1/16" tip for neater work.
N.B. read LED precautions for ESD handling and soldering use 3 sec time. max

Get only 74ALC14N 6 Schmitt Inverters that with 5~10M Resistor and 0.1uF caps make 6 Relaxation Oscillators. The 74ALC versions work well at 3V with a driver resistance of 20 Ohms

I would suggest Li-ion rechargeable CR123A or 18650 size cell’s with a battery holder.

These 74ALCxx CMOS IC's are lower ESR than 74HCxx series and R values shown below to suit hi/lo side and colour Vf but you may vary slightly to desired current, which you measure by R, voltage drop.

Thus gets you 6 independent flasher LED drivers , not 8 but you can string Two LEDs and small series R, and drive the midpoint for complementary lights in the sides then have more three on top and 3 alternate horizontal pairs

schematic

simulate this circuit – Schematic created using CircuitLab

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  • \$\begingroup\$ Maybe someone can sketch a quick schematic. (Edit) But you will need to learn how to make a neat solder joint and convert PIN numbers to a wiring layout in a protoboard (see Instructables) \$\endgroup\$ – Sunnyskyguy EE75 Jul 17 '18 at 11:14
  • \$\begingroup\$ Why a bunch of schmitt triggers, caps, and resistors? Why not use inexpensive two lead "blinking RGB LEDs"? That's a search term, try using it. \$\endgroup\$ – Misunderstood Jul 17 '18 at 20:14
  • \$\begingroup\$ Yes. If they want to pay 10X what they cost on eBay or Amazon. Not sure how well they can be soldered with a 25-35 watt iron or powered with a CR123A rechargeable battery. \$\endgroup\$ – Misunderstood Jul 17 '18 at 20:35
  • \$\begingroup\$ They even work off a 3V CR3032 only dimmer at 5$ per (RGB) LED cheap ( vs 10 cents and his time $$) \$\endgroup\$ – Sunnyskyguy EE75 Jul 17 '18 at 20:36
  • \$\begingroup\$ It's not IF they will work, it's how well they will work. You need to evaluate the discharge curve cutoff voltage. When powering LEDs the cutoff voltage is more important than the battery's nominal voltage. It does no good to have the LED too dim when there is still a lot of unusable capacity left in the battery. \$\endgroup\$ – Misunderstood Jul 17 '18 at 20:42

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