SparkFun Forums

[p0g0]

Hallo,

I am looking for a design to attach it on the bottom of my inline skate. a board thats powered from a 3.7V lithium battery, which can be charged from the USB port. preferably as small as possible, 4 by 5 cm (1.5 bij 2 inch). An Arduino-based custom design. 8 separate powerfull RGB LED outputs. And if possible/ unnecessary a mico microphone and waterproof.
Is the idea possible to make? If so, and which equipment do I need to buy? Btw, i know nothing about soldering.
it must seem like a spider with separate RGB LEDs on each leg.
thanks for helping.

[Mee_n_Mac]

How powerful are these "powerfull RGB LED outputs" ? Sounds like some driver circuitry is also needed.

[p0g0]

it should stand out in the dark from a distance. Perhaps as powerful as possible, so take your pick

[Mee_n_Mac]

More than the RollerBrights ?
http://rollerbrights.com/
http://www.youtube.com/watch?v=VssuptYUknA
Or these ?
http://www.youtube.com/watch?v=4zsYUD84U3Y

Also how long should the battery last ?

My GUESS is these might be a good starting point for brightness and beamwidth.
https://www.sparkfun.com/products/11679

[p0g0]

looks good, but the batterry is too large therefore a smal lithium 3.7v battery is fine. Is this possible with that design? Take a look at this design: I hope this is not a copyright. http://www.thephotonfactory.com/PD-V1-24.shtml but this one only works with 5v and more:(
Btw, The battery duration does not matter min 2-3 hours

[Mee_n_Mac]

Do all 6 LEDs on a skate need to be independently controlled or are all 6, each the same as the other, but otherwise having group control for brightness and color OK ?

Also you can't run B and G LEDs off of a single cell LiPo w/o some DC/DC voltage booster. So it's add some booster circuitry or get a higher battery voltage.

FWIW - by spec the LEDs I linked to are brighter than those above.

[p0g0]

independently controlled would be nice (for having a rainbow effect) . group control is also ok.
I just love that you can change the location of each LED.

Btw, thanks for the info so far.

[Mee_n_Mac]

looks good, but the batterry is too large therefore a smal lithium 3.7v battery is fine. Is this possible with that design? Take a look at this design: I hope this is not a copyright. http://www.thephotonfactory.com/PD-V1-24.shtml but this one only works with 5v and more:(

FWIW - This and the right LiPo cell (also suggested below) would allow you to use the product above.
https://www.sparkfun.com/products/11231 (very long time recharge the batteries below)

https://www.sparkfun.com/products/339 (1+ hrs runtime)
https://www.sparkfun.com/products/8483 (obviously 2x the above)

And these plus 18 resistors could be used to make your own controller (albeit w/"group" control only)
https://www.sparkfun.com/products/11114
https://www.sparkfun.com/products/9627

[p0g0]

which one do you recommend?
-I do not think that the plasmadrive gives a lot of light on 3.7v.
-Arduino Pro Mini 3.3V: can i put an Arduino code on the chip so that the leds work separately?
-which holes do I need for each LED? and also for the other board.

[Mee_n_Mac]

which one do you recommend?
-I do not think that the plasmadrive gives a lot of light on 3.7v.
-Arduino Pro Mini 3.3V: can i put an Arduino code on the chip so that the leds work separately?
-which holes do I need for each LED? and also for the other board.

I don't have a recommendation. If you like to tinker w/the electronics or have some custom light show, then the DIY approach using the SF parts might be fun. Be aware the end product will be larger and cost more than the store bought plasmadrive system. Unless you design and build your own custom PCB.

I would add that by using the DC/DC voltage booster, the plasmadrive runs at 5v, same as it normally does.

One recommendation I do have is to forget the "in skate" recharging, use just a DC/DC voltage booster, not a DC/DC voltage booster/charger ... and swap batteries in/out, recharge them in a separate fast charger.

To get control of the RGB LEDs separately, you needs 18 output pins, which you don't have on the Pro Mini. You can expand using shift registers or LED driver ICs. It just more parts and more space needed.

Or use addressable LED strips, though I'm unsure how bright the included LEDs are. This would be the simplest system of all; a controller, a strip, a battery and a DC/DC voltage booster. For example;
http://learn.adafruit.com/neopixel-cyber-falls
You can buy the NeoPixels separately and you might get away w/o the DC/DC voltage booster (albeit w/reduced brightness and runtime).
http://www.adafruit.com/products/1312#Technical_Details
https://www.sparkfun.com/products/11821

[p0g0]

I found something, I hope a cheap solution! http://www.adafruit.com/blog/2013/06/28 ... e-tlc5947/ . can you have a look? thanks

[Mee_n_Mac]

That's the LED driver IC I had in mind a few posts ago. That plus a microcontroller plus a battery and DC/DC booster plus LEDs gets you individual control of all the LEDs, just like the Plasmadrive unit. It's nice that Adafruit has mounted it on a PCB. The one SF sells can only do 12 LEDs.

FWIW the Neopixels are as bright as the Plasmadrive LEDs (I suspect they are clones of each other), making them output about 40% of the light output of the Piranha LEDs I initially linked to. Given the logarithmic response of human vision, there may only be a very slight difference in perceived brightness. Perhaps a more important spec is the beamwidth. The Piranha are 90 deg, and the Neopixels and clones are 120 deg, giving a more floodlight-like patch of light under the skate.

[Mee_n_Mac]

BTW no matter what hardware is finally used, it has to be controlled somehow and that means software. Now perhaps you could come up a few preset sequences of colors and brightnesses and store them all in the controller's flash memory, but I note that the Plasmadrive people claim their controller will hold "76 unique slots with adjustable hold and fade rates". Apparently there's some software you run on the PC to create a sequence of up to 76 different colors, etc. You then download this sequence into the Plasmadrive controller. Absent the Plasmadrive PC program, how would you configure your skates "sequences".

[p0g0]

Which 5v booster is the lightest and smallest?
So all summary:
*plasmadrive: all in 1 board. Needs an extra 5v DC/DC booster. Perfect for under the skate. I hope that pc program is available. 51 dollar.
*Adafruit: also needs a 5v booster? An extra microcontroller (FTDI Basic breakout 3V3 or 5v ?). and some control buttons. + 2x neopixel packs. more then 51 dollar.
Is this correct?

[p0g0]

I think I choose adafruit. i found a seller in my country. so no extra cost for shipment. So now I have to choose the right pieces to buy. A 24-channel board + FTDI breakout board (3v or 5v?) + battery + neopixels + a DC/DC booster + buttons. Do i miss something?