Neopixel stick

[Ben]

I have connected the Neopixel stick to my Naze board, but am having some trouble controlling them. If anyone can help, that would be great.. Some details :

Neopixel stick will power on with all LED';s yellow.

RX_PPM selected and LED';s enabled on the config page.

Should mention it';s Cleanflight 1.7 I';m using.

I can set the 8 LED';s on the LED page to point South, display arm/indicator etc in GUI, but nothing changes the yellow colour they are displaying.

I';m drawing the power from a separate BEC that';s providing ~5.4v, which I have read could mean it';s too high. Although those reports suggest the strip will not come on at all. The signal is connected to the 5th pin on the RC Input, with the ground for that to one of the ESC inputs ground. (I have tried to ground it to the RC Inputs ground)

I';m at a bit of a loss as to what it is. I have tried on a spare board as well!

Will it be something simple I';ve overlooked? 

[quadfather]

I have connected the Neopixel stick to my Naze board, but am having some trouble controlling them. If anyone can help, that would be great.. Some details :

Neopixel stick will power on with all LED';s yellow.

RX_PPM selected and LED';s enabled on the config page.

Should mention it';s Cleanflight 1.7 I';m using.

I can set the 8 LED';s on the LED page to point South, display arm/indicator etc in GUI, but nothing changes the yellow colour they are displaying.

I';m drawing the power from a separate BEC that';s providing ~5.4v, which I have read could mean it';s too high. Although those reports suggest the strip will not come on at all. The signal is connected to the 5th pin on the RC Input, with the ground for that to one of the ESC inputs ground. (I have tried to ground it to the RC Inputs ground)

I';m at a bit of a loss as to what it is. I have tried on a spare board as well!

Will it be something simple I';ve overlooked? 

When you say 5th pin do you mean the pin that';s labelled 5?  It should be the 7th pin, which is labelled 5.  That pin needs to connect to DIN on the strip/stick.

5.4V is probably too high.  From what I gather the control voltage is ~5V (on pin 5) and the supply voltage to the LEDs needs to be below that.  Unfortunately I don';t have any LED strips to test this myself.

[Ben]

Hi Quadfather,

Yes, It';s pin 5, rather than the 5th one in  :embarrassed. Looks like I';ll have to try and reduce the voltage somehow and see if that gives any results.

Cheers 

[Paul01]

Have you tried adding a capacitor to the first pixels + -, 1000uf 6.3v as recommended. Of you don';t it can';t shorten there life or even damage them

[Ben]

Hi Paul, I hadn';t seen that recommendation. Where abouts did you see that?

Ben

[Paul01]

Adafruit website

https://learn.adafruit.com/adafruit-neopixel-uberguide/power

I use Neopixel';s a lot with arduino and i have never had issues running them at 5v, but i always use a capacitor as each pixel has a small micro controller that needs stable power. I think the reason people find dropping the voltage works is because this increases the available amps reducing brownouts.

not adding a capacitor also causes flickering in the leds (not always visible) and this slowly kills them.

[Ben]

Cheers Paul.

Got to say, I don';t know much about capacitors, other than there';s loads of different types  Could I ask what ones you use?

[Paul01]

This is what you need

http://www.ebay.co.uk/itm/CAP-ALU-ELEC-1000UF-6-3V-RAD-Part-NICHICON-UVZ0J102MPD1TD-/271668592912?pt=UK_BOI_Electrical_Components_Supplies_ET&hash=item3f40b5c110

[Ben]

That';s great. Thanks Paul 

[Paul01]

If you just need the one i have some spare

[Ben]

Thanks for the offer, but I just popped in Maplins and grabbed 2. I even managed to leave the shop with my trousers up and some money left in my wallet, so that was a nice surprise! 

[Paul01]

i try and order all my bit from China in advance, it kills me to go in there.

[Ben]

Normally does me, but at £1.16 for 2, I thought I got away lightly...

Just added one in line, but I still need to drop the voltage to match the signal voltage (or below). Will check out what other ubecs I have to see what they are producing.

[Paul01]

That';s not bad for Maplin. I';ve seen a thread online were some one had to drop the voltage 4.1v to get them working.

[Ben]

I';ve seen a similar voltage mentioned as well. Will have to try one of the voltage regulators I ordered the other day, when they arrive.

[Paul01]

the other way to do it would be to boost the FC';s pin with a transistor

[Ben]

Now we';re getting complicated, I doubt I could work that out!

I had looked at just adding a resistor. The manufacturers suggest that the LEDs use around 20ma each, or a maximum of 60ma.. If I split the difference and go with 40ma, an input of 5.4v and a required of 4.1v, then I believe a 4.3 ohm, 1/2watt resistor should do it...

[Paul01]

the only problem with using a resistor is, your device needs to constantly pull the same current or the voltage change. If you had a variable resistor you could see how much you need to drop the current to get it working and find out if your still happy with how bright the pixels are.

[Ben]

Good point. If I add warning lights, or indicators, then the draw will be changing constantly...

Cheers for all your help Paul, it';s much appreciated 

[Paul01]

No problem

[Ben]

I added a voltage regulator today and dropped the voltage to about 4.4v. All working well now.

https://vimeo.com/119137182

They change colour on arming, have left and right indicators and they flash when reversing. Will look at setting up a low voltage warning on them later.

Cheers for all the help 

[Ben]

I should probably mention here, in case anyone else is having the same trouble, that this is the regulator I used -

http://www.ebay.co.uk/itm/LM2596-DC-DC-Switching-Adjustable-Step-Down-Voltage-Regulator-Buck-Converter-/271632729700?pt=LH_DefaultDomain_3&hash=item3f3e928664

I turned it down to about 4.4v as a first guess to try it and it worked, so have left it there. I have read that they will work at slightly higher voltage, as long as it';s below the 5v signal feed from pin 5.

[Chippercheese]

I should probably mention here, in case anyone else is having the same trouble, that this is the regulator I used -

http://www.ebay.co.uk/itm/LM2596-DC-DC-Switching-Adjustable-Step-Down-Voltage-Regulator-Buck-Converter-/271632729700?pt=LH_DefaultDomain_3&hash=item3f3e928664

I turned it down to about 4.4v as a first guess to try it and it worked, so have left it there. I have read that they will work at slightly higher voltage, as long as it';s below the 5v signal feed from pin 5.

I usually power my neopixels from a redundant BEC on one of my ESCS, nice "clean" 5v 2A supply, then send data separately. Works like a charm.

[Paul01]

I should probably mention here, in case anyone else is having the same trouble, that this is the regulator I used -

http://www.ebay.co.uk/itm/LM2596-DC-DC-Switching-Adjustable-Step-Down-Voltage-Regulator-Buck-Converter-/271632729700?pt=LH_DefaultDomain_3&hash=item3f3e928664

I turned it down to about 4.4v as a first guess to try it and it worked, so have left it there. I have read that they will work at slightly higher voltage, as long as it';s below the 5v signal feed from pin 5.

Just got my Naze32 today and have been playing with some neopixels, when wired the Naze to the neopixel did you just this with just pin 5 or did you wire a ground from the Naze to the neopixels as well?

[Ben]

I used a ground as well. I just went on to one of the ESC/Servo headers with it. Seems to work fine like that.

[Paul01]

I have them working at 5v when the Naze is powered by USB, so the issue you had must be to do with the Naze';s internal voltage regulator

[Ben]

Must be something to do with that. I could have tried another bec from one of the ESC';s I suppose, but the voltage reg only weighs 12g and is working - So may leave as is now. The Spanky weighs about 800g with the GoPro3 and a 2200 4s battery, so the 12g isn';t going to make much difference. If it ain';t broke... 

[Paul01]

Definitely, I';m just playing with a naze at the moment I';ll let you know if I get it setup with out using a bec

[Stalker]

Adafruit website

https://learn.adafruit.com/adafruit-neopixel-uberguide/power

I use Neopixel';s a lot with arduino and i have never had issues running them at 5v, but i always use a capacitor as each pixel has a small micro controller that needs stable power. I think the reason people find dropping the voltage works is because this increases the available amps reducing brownouts.

not adding a capacitor also causes flickering in the leds (not always visible) and this slowly kills them.

I';ve got two of these sticks that I';m using in series for a rear light bar. I';m running them of an unused ESC power supply. To start with, they work fine. After a while, they start flickering and changing colours at random. Will one of these capacitors you';ve linked to stop the weird behaviour? I don';t really want to add a variable resistor due to weight and size of it on my 250.

[Paul01]

I would recommend adding a capacitor, but the issue you are mentioning suggest you haven';t got a good common ground between your ESC and FC. I would suggest if you don';t have already linking the ground from the Neopixel to the ground on the FC