# Help making light up nerf gun

#### Stygs

Joined May 19, 2019
8
Hey guys this is my first electronics project so I'm trying to figure out the best way to make this work. I'm taking a nerf gun and making a steampunk gun that lights up. I want the lights to change colors and to slowly pulse.

My biggest questions are which controller to use that can run on a battery and is small, and how to make the tubes in the cylinder and on the body of the gun light up, but still have a moving cylinder in the gun and which button/selector I should use so that I can cycle through the colors.

The last question is this: I have individual rgb LEDs and in all my digging online I can't find an answer to how/whether you can connect these in series.

I can post pictures of the gun or parts I already have if that would help.

#### Wolframore

Joined Jan 21, 2019
2,195
Suggest using a small Arduino like a NANO or MINI. Also look into addressable light strips. You can control 100's of them using one arduino pin... search google for Nerf Ardunio projects... you will find tons of examples and step by step instructions... start there and branch off and make your own version.

#### Yaakov

Joined Jan 27, 2019
1,612
Welcome to AAC.

I would suggest you look into WS8211 "NeoPixel" addressable LEDs (as @Wolframore mentioned). They will make things much simpler overall.

#### Stygs

Joined May 19, 2019
8
Suggest using a small Arduino like a NANO or MINI. Also look into addressable light strips. You can control 100's of them using one arduino pin... search google for Nerf Ardunio projects... you will find tons of examples and step by step instructions... start there and branch off and make your own version.
I looked into the arduino nano and mini and i was reading that they aren't good for battery powered systems. I also read that it can drain a 9v battery in a day and I don't have the space for a 9v. Any opinion on that?

#### Stygs

Joined May 19, 2019
8
Welcome to AAC.

I would suggest you look into WS8211 "NeoPixel" addressable LEDs (as @Wolframore mentioned). They will make things much simpler overall.
I don't think a light strip would work. I see they make a neopixel flora which I think would work. I'll have to get some of those. Thanks!

#### Wolframore

Joined Jan 21, 2019
2,195
9 volt batteries are expensive and low power... they don't work well period. You will have to solve the power issue... 9 volt battery running lets say 10 LED's at 20mA with the proper resistors will last maybe couple hours period even without the arduino. What will control it for less than 20-25 mA that the arduino needs and with the same sort of control you might want? How did you come to this conclusion?

Actually there are ways to minimize power usage using an Arduino like using PWM and other tricks...

#### Stygs

Joined May 19, 2019
8
9 volt batteries are expensive and low power... they don't work well period. You will have to solve the power issue... 9 volt battery running lets say 10 LED's at 20mA with the proper resistors will last maybe couple hours period even without the arduino. What will control it for less than 20-25 mA that the arduino needs and with the same sort of control you might want? How did you come to this conclusion?

Actually there are ways to minimize power usage using an Arduino like using PWM and other tricks...
I was digging around online and found a forum or article on Arduino nano power use. I've looked at raspberry pi as well but they seemed like over kill for what i'm doing. I wasn't sure if there was another option comparable to an Arduino. I've been looking into circuitry for all of a week that's why I hopped on a forum to see what others could tell me.

#### Wolframore

Joined Jan 21, 2019
2,195
you could use 555 timers or counters but they will need more components and circuit will grow based on what you need. If it’s a simple pattern this may be the solution. You won’t be using those addressable LEDs with analog circuitry. It’s doable... but more work and parts.

#### Yaakov

Joined Jan 27, 2019
1,612
I don't think a light strip would work. I see they make a neopixel flora which I think would work. I'll have to get some of those. Thanks!
The WS8211 is packaged in a variety of ways, even in 5mm packages.

#### Wolframore

Joined Jan 21, 2019
2,195
Without the FTDI chip for usb and disabling the onboard LEDs I believe the Arduino processor needs 2.4 mA @ 5V. If you don’t need the speed you can get power consumption under 1mA running it at 3.3v and 1MHz but I find 5v useful for driving MOSFETs. Look into Pro Mini which does not have the FTDI chip. They’re about $10 genuine and$2 clone.

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#### Bernard

Joined Aug 7, 2008
5,720
3 color LEDs have either common anode or cathode which makes series connection impossible
At a given time are all LEDs of the same color?

#### Stygs

Joined May 19, 2019
8
3 color LEDs have either common anode or cathode which makes series connection impossible
At a given time are all LEDs of the same color?

Yeah all would be the same color at the same time. I'm making The tubes glow, and 4 more on other parts of the body of the gun glow. Ideally I'd like the cylinder to still move but if you guys think that's going to be impossible without making a separate battery and circuit I can always lock it in place.

Picture is the guts of the gun. I can post the external view as well if you think that would help

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#### djsfantasi

Joined Apr 11, 2010
7,250
Yeah all would be the same color at the same time. I'm making The tubes glow, and 4 more on other parts of the body of the gun glow. Ideally I'd like the cylinder to still move but if you guys think that's going to be impossible without making a separate battery and circuit I can always lock it in place.

Picture is the guts of the gun. I can post the external view as well if you think that would help
I’m only going to answer one part of your question, you CAN make the lights work in your rotating cylinder. If you can make a slip ring somewhere on the cylinder or it’s axle. You need concentric rings for each lead (I.e., RGB) plus one for ground. Then somewhere in the body you need contacts that will run against the rings and connect to ground and the individual RGB supply leads. Search from brass strip to find the materials for the rings and contacts.

#### Wolframore

Joined Jan 21, 2019
2,195
what do you want it to do? how many led's are we talking about? what are the limits?

#### djsfantasi

Joined Apr 11, 2010
7,250
Yeah all would be the same color at the same time. I'm making The tubes glow, and 4 more on other parts of the body of the gun glow.
If all you want is to make the tubes glow and will always have white lights, then you are better off using white LEDs. Overall, you’ll draw much less current and will avoid having to add extra circuitry for higher current. Which will offset buying the white LEDs.

#### Wolframore

Joined Jan 21, 2019
2,195
Ohhh then why control it? Just put a switch in. I thought we were going to have fun with it.

#### djsfantasi

Joined Apr 11, 2010
7,250
Ohhh then why control it? Just put a switch in. I thought we were going to have fun with it.
The TS has another requirement to make the lights “pulse”. We haven’t gotten to that part yet, since we can’t even light them at all.

#### Wolframore

Joined Jan 21, 2019
2,195

I want 20 LED's to blink and pulse change colors... fit in my nerf gun and run for a year on a 9V battery... with no controllers... 1 mA is too much power.

oh and make everything fit inside without interfering with anything

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#### Bernard

Joined Aug 7, 2008
5,720
Do you already have the 3 color LEDs? Something like Kingbright WP154A4 ? Is it 10 LEDs, really 30.
Would it be acceptable to change color with each pull of trigger ?
Might make slip rings from 1/8 in. Cu. tape around cylinder ?
Can battery pack be external, like on a belt clip ?
What are dimensions inside of the handle ?