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Topic: Arduino Lightsaber for/with LED string blade (Read 56645 times) previous topic - next topic

shiryu55


New tests, with the neopixel strip of 144led cut to 119 led, with a single string works ok, with 2 comes out the failure of low battery, but if it happened to connect it to the fet, and I connect it to negative of the battery and arduino mass It works properly, but that way I commit protonerd that it spends battery even at rest.

The thing is that I do not know because I miss the way by connecting it to the fet, one all 6 Fet to the negative of the neo pixel strip, positive to battery and pin 13 to signal.

On the other hand with the led strip 60 led and only 4 Fet works, then incorporate the other two Fet to the plate to see if it was for low mass or not to put the 6 fet, with the other led type cree sin Problems too



Which smd fet me you recommend, just because I do not use the appropriate ones


http://subefotos.com/ver/?71f23318548ced07a93c688aa97b1f93o.jpg
http://subefotos.com/ver/?fd6d214b1ba773970bbffcdee2ca269co.jpg


jesjhoward

Hi all, I'm having a bit of an issue with my arduino based saber. I think I know what the issue is, but I need some master-class guidance. I have the arduino, DFPlayer, and MPU 6050 wired properly and powered by two 14500 batteries. I'm using two neopixel strips at 144 leds per meter. Each strip has less than 119 leds (due to bad tests and repairs, lol) but the problem comes in when using the flash on clash feature, or any function that turns all leds white. The second this happens the board shuts down. I'm guessing that the leds are pulling too much current for the batteries to handle. Does this sound right? Any suggestions on how to improve this set up? Thanks guys!

Protonerd

Yes, your assumption is correct. I had the same issue when using 2x120 pixels and a protected 18650 battery. When the overcurrent protection is triggered, the battery shuts down, so does your circuit too.

You can do 2 things:
- reduce the pwn to a max of (?) 100
- swap the batteries with unprotected ones, but beware of the heat

Since I use an unprotected cell, I can turn on all pixels full, of course with the 3.7V and all the IR drop the voltage is reduced, so the full brightness cannot be reached, but hold the saber for a few minutes and you will feel the "heat of the action" :)

Andong

#663
May 13, 2017, 07:14 am Last Edit: May 13, 2017, 09:08 am by Andong
Hi all. Recently started building a lightsaber using all the usefull info and tools everyone kindly shared but after some testing and couple burned hp-leds i've got couple questions:

1. In the schematics you use 100k resistors but i didn't find any notes if it's supposed to be 0.5w, 1w, 2w or any other?

2. I tried single 18650 battery with dc-dc step up connecting it to 5v pin on arduino but it doesnt seem to work, well it powers up but instead of normal sounds the df player starts to produce some crackling sounds. So i switched to 2x16340 to get 7.4-8.2v. As for mosfets i tried 2 different types

IFRD120PBF - https://www.amazon.com/10PCS-IRFD120PBF-MOSFET-4-DIP-IRFD120/dp/B01DI5ZZOO/ref=sr_1_4?ie=UTF8&qid=1494651293&sr=8-4&keywords=irfd120

IRLD024 - https://www.amazon.com/5PCS-IRLD024-MOSFET-N-CH-4-DIP/dp/B01973D5TI/ref=sr_1_1?ie=UTF8&qid=1494651721&sr=8-1&keywords=irld024

With IRFD120 the led lights up and sounds are played but i noticed that some of the colors are way brighter than others. So i connected mulitimiters to red, green and blue lines of hp-led and based on the data sometimes the voltage is really low(certain colors), for exmaple it may be 2.5v on green or blue led so overall it's pretty dim. But with some colors the voltage may jump up to 4-4.2v. So i started to wonder if it is normal or i'm doing something wrong?

With IRLD024 one i turn on the lightsaber it lights up but instaed of normal sounds i get that constant loud crackling. So then again i started to wonder if i'm doing something wrong or just IRLD024 isn't fit for this?


Protonerd

Hi all. Recently started building a lightsaber using all the usefull info and tools everyone kindly shared but after some testing and couple burned hp-leds i've got couple questions:

1. In the schematics you use 100k resistors but i didn't find any notes if it's supposed to be 0.5w, 1w, 2w or any other?

2. I tried single 18650 battery with dc-dc step up connecting it to 5v pin on arduino but it doesnt seem to work, well it powers up but instead of normal sounds the df player starts to produce some crackling sounds. So i switched to 2x16340 to get 7.4-8.2v. As for mosfets i tried 2 different types

I would advice you to grab a DIYino Prime board instead of expermenting. Proven, reliable and you can focus on programming the effects you would like to have.

As to the supply scheme you used, with a single 18650 (3.7V) battery you will be very close to undervoltage for most of the chis on board. If you on top of it turn on the LEDs, which causes a substantial inrush of current, ground shift and IR drop over the wiring will cause the voltage to drop even further. I also know from expeience that the first module which will fail to work is the audio amp, hence the crackling sounds. I made once a E11 blaster using a single cell, works, but there I have only small burst of lights whereby in a lightsaber the lights are continuosly on.

In terms of mosfets, it's important to select those which can carry a min of 2A, low Rdson and logic level (meaning a Vgs threshold not greater than 2.5V). If the Vgs is close to your battery, the fets are not fully in which could explain the dimness. And if your red LED will switch on earlier than the blue and greed due to a lower threshold, it could "steal" the current from the other 2 if your battery cannot supply enough current for all 3.

Andong

#665
May 13, 2017, 02:17 pm Last Edit: May 13, 2017, 02:30 pm by Andong
In terms of mosfets, it's important to select those which can carry a min of 2A, low Rdson and logic level (meaning a Vgs threshold not greater than 2.5V). If the Vgs is close to your battery, the fets are not fully in which could explain the dimness. And if your red LED will switch on earlier than the blue and greed due to a lower threshold, it could "steal" the current from the other 2 if your battery cannot supply enough current for all 3.
Thanks for a fast reply, Protonerd. As for now it became kind of a challenge for me to complete a fully working lightsaber with the components i already have :) But for the next one i'll definetly grab a DIYino, put my eyes onto Stardust version.

According to IRLD024 datasheet it can carry up to 2.5A, the Vgs threshold is 1V to 2V and Rdson is 0.1, also in the datasheet it states a logic-level. So if i understand correctly it's supposed to be good but for some reason once lightsaber is powered there is constant loud crackling.

As for IRFD120, again according to the datasheet it can carry up to 1.3A, Vgs threshold is 2-4V and Rdson is 0.27. Does it mean it's not logic level thus not suited for a lightsaber project?

Sorry if my questions sound dumb but i'm new to all this stuff, just recently got interested in electronics.

Protonerd

No stupid question, only stupid people who do not dare to ask. If a transistor has 2-4V Vgsth, you need a 5V supply. I would anyway urge you to use either a DC/DC to boost your 3.7V to 5V or power the board over the VIN with >6V. But then there should  not be any crackling. Did you have any Wav files on the SD card you use? If yes, in the right format?

Andong

#667
May 14, 2017, 04:50 am Last Edit: May 14, 2017, 06:35 am by Andong
No stupid question, only stupid people who do not dare to ask. If a transistor has 2-4V Vgsth, you need a 5V supply. I would anyway urge you to use either a DC/DC to boost your 3.7V to 5V or power the board over the VIN with >6V. But then there should  not be any crackling. Did you have any Wav files on the SD card you use? If yes, in the right format?
All contents of SD card is made according to LSOS readme on github. (I use LSOS 1.4)

Tried powering with 3.7v and boosting it to 5v with dc-dc converter. First i tried connecting to VIn but then i found your post that need to connect to 5v pin so i tried it but sadly same thing with crackling sounds.

With 2x16340 baterries the voltage is 7.4-8.2V. If using IRFD120 mosfets i get some of the colors dim and some are perfectly fine(sometimes the voltage is even too high, around 4-4.2v on green or blue) but everything works including sounds and motion/clash detection. Also, based on the mulitmeter readings, voltage fluctuates but as i understand it's made on purpose and based on the sounds played by df player(kinda represents the hum).

If i switch mosfets to IRLD024 (based on the datasheet those seemed more suited) and turn lightsaber on i get the crackling sounds. My first thought was that mosfets were defective but i have 6 of those and tried all with same outcome. So either all 6 are defective or they aren't suited for this project for a reason i don't understand.

Protonerd


New DIYino Prime v1 boards ara available from the 5th Run, sale is open as of NOW. If you are interested, drop me a PM. For conditions, look into the DIYino thread.

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