Powering NovaGem CDR's with USB Power Tap Cable

[lisowskikevin]

Hey guys,

Anyone try powering the 5V Novagem Coin Door Buttons with a USB Power Tap cable? Would I need 4 USB Power Tap Cables cables in 4 separate USB slots for the 4 Novagem buttons I have?

[keilmillerjr]

Not sure exactly what you have, but I'm pretty sure it is unnecessary to hog 4 USB ports. Daisy chain or split the wires.

[BorgDog]

According to GGG's site the LEDs use 100ma each, so your 4 would be 400ma, I believe a standard USB can only do 100ma, so you would need 4 separate ports to make it work.  I would either pull it right from the PC power supply if you have one or a 5V wall wart you probably have lying around.

[lisowskikevin]

According to GGG's site the LEDs use 100ma each, so your 4 would be 400ma, I believe a standard USB can only do 100ma, so you would need 4 separate ports to make it work.  I would either pull it right from the PC power supply if you have one or a 5V wall wart you probably have lying around.

Hmm, thanks for the info.....any certain specification of wall wart I should be getting?

[BorgDog]

Anything that says 5v and 500ma or greater I would say would work.  Any of the usb type phone chargers should work.

[keilmillerjr]

According to GGG's site the LEDs use 100ma each, so your 4 would be 400ma, I believe a standard USB can only do 100ma, so you would need 4 separate ports to make it work.  I would either pull it right from the PC power supply if you have one or a 5V wall wart you probably have lying around.

USB Power Delivery profile 1 specifies +5v 2amps. The wikipedia article is a good read.

http://en.m.wikipedia.org/wiki/USB

[BorgDog]

From that article

The Power Delivery specification defines six fixed power profiles for the power sources. PD-aware devices implement a flexible power management scheme by interfacing with the power source through a bidirectional data channel and requesting a certain level of electrical power, variable up to 5 A and 20 V depending on supported profile. The power configuration protocol uses a 24 MHz BFSK-coded transmission channel on the VBUS lin

somehow i done think the led lights are going to be doing that.

[MonMotha]

Normal USB without any of the extra power add-ons is 5V @ 100mA unless you ask for more, but almost all desktop PC USB ports (and most laptop ones) are capable of providing the enumerated maximum of 5V @ 500mA even without enumerating.

In other words, you can PROBABLY pull 5V @ 500mA off any given PC USB port with no other electronics needed, but it's technically against the spec to do so.

Your average USB phone charger is even dumber.  It's just a 5V supply that's good to either 500mA or 2A (or something else - read the label).

[lisowskikevin]

Normal USB without any of the extra power add-ons is 5V @ 100mA unless you ask for more, but almost all desktop PC USB ports (and most laptop ones) are capable of providing the enumerated maximum of 5V @ 500mA even without enumerating.

In other words, you can PROBABLY pull 5V @ 500mA off any given PC USB port with no other electronics needed, but it's technically against the spec to do so.

Your average USB phone charger is even dumber.  It's just a 5V supply that's good to either 500mA or 2A (or something else - read the label).

Phone charger is dumber? But all I need is 400ma from a 5 V supply I thought?

[BorgDog]

I believe MonMotha means the phone charger is dumber than the computer, in that it doesn't care whats attached to it, computers usb ports determine the charging by talking to the device.  A phone charger imho is the easier and smarter device to use for this.

[lisowskikevin]

I believe MonMotha means the phone charger is dumber than the computer, in that it doesn't care whats attached to it, computers usb ports determine the charging by talking to the device.  A phone charger imho is the easier and smarter device to use for this.

Gotcha thanks for the clarification.

[lamprey]

Are you using a computer for this project? If so, it seems easier to just use a 5 volt line from the power supply.

[lilshawn]

by default USB will output 100ma.

if a device requests (during it's connection negotiation) for more current the port will switch to a 500mA output

SOME motherboards offer up to 1800mA output specifically for charging devices. (notably Gigabyte offers this feature)

your power supply in your computer on the other hand supplies several AMPS worth of 5 volt...just get it from there.