Hi Guys,
Quick question how can i draw about 21 amps rated at 12 volts from gadeteer board, i am buying a huge led strip
which will draw that much current and voltage, since the led is not gadgeteer based so i will be using the extender module and the extender
module can only deliver a max of 5 volts, please help me
Perhaps something like this: https://www.sparkfun.com/products/12959
@ suitable1 - Thank you for your reply but i am very new to this, i dont know how to use it, is there a tutorial somewhere that tells you how to hook it up and how about using it?
@ sohail10 - You cannot power any more than a handful of RGB LEDs directly off the board. Instead, you need to supply the +12v to the strip from a separate power supply.
There are several options:
[ul]Switching power supply, like this one: 12V 5A switching power supply : ID 352 : $24.95 : Adafruit Industries, Unique & fun DIY electronics and kits - Advantage is that they’re easy to use, and portable. But you’ll need more than one (you can break the power circuit and connect in the additional power in the middle of the strip).
I’ve also used FrankenPSUs, which is basically a homemade bench power supply made from a PC PSU with the 5v and 12v (and/or other voltages) supplies wired to banana plugs on the case. These are cheap, but heavy. They can supply a lot of amps, but with LED strips, you still don’t want to supply all the power from one end, as the LEDs toward the other end will start to get dim, since they won’t get enough power. This route is also potentially very dangerous if you don’t know what you’re doing, since there are some very high capacity capacitors in a PC PSU…as in enough to kill you. Tread carefully.
Dedicated PSU like this (but in 12v for your needs…this one is 5v): http://rgb-123.com/product/5v-60a-power-supply/ Downside here is that these are large, heavy, and expensive.[/ul]
Adafruit has an excellent tutorial on LED strips, which discusses some of the power issues. Definitely worth a read, even if you’re controlling these with NETMF.
Hope that helps!
1 Like
@ devhammer - Thank you for detailed reply. I wasn’t going to power the leds directly from the board, i knew i had to use an external power but my problem is how about wiring everything up. I am getting the rgb led strip from adafruit but they wired everything in arduino.
I will use a separate power source for leds but i will be connecting the signal wires to the extender module, i just dont know how to wire it with .net gadgeteer.
@ sohail10 - The key is that the ground from the power supply, and the ground from the microcontroller need to be connected. The +12v from the power supply (or supplies) should never connect to the microcontroller. The signal pin from the microcontroller gets wired up the same way as you would with an arduino, but depending on which Gadgeteer socket you’re using, you might need to use a different pin.
I’ve not used analog LED strips myself, but you might find this documentation helpful as well:
https://www.ghielectronics.com/docs/10/analog-outputs
It doesn’t speak specifically to LED strips, but rather on how to control analog outputs in NETMF. You may also want to look at the Gadgeteer socket chart:
https://www.ghielectronics.com/docs/305/gadgeteer-sockets-quick-reference
as that will help you figure out which sockets expose analog outputs.
Finally, this doc is helpful for finding the right pin on a socket when working in plain NETMF:
https://www.ghielectronics.com/docs/144/plain-netmf-on-gadgeteer
Hope that helps!