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Author Topic: alternative power supplies  (Read 1650 times)

Offline pelgrim

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alternative power supplies
« on: June 13, 2016, 02:36:14 AM »
Did anyone try to power sprout with an adaptor, or even better, using the power of a usb cable and some power conversion if that is needed ?

The usb solution would be perfect, but anything that replace the batteries will do.

Offline sam

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Re: alternative power supplies
« Reply #1 on: June 14, 2016, 11:26:10 AM »
Yes the Sprout can easily be powered with an external adapter, but be sure to measure and check that the output of your supply is 5v or less (high voltage can burn out the 328p)

I have used simple 'phone' chargers for older phones, cut off the strange end connector and add two pins of male header.  cutting up USB cables is a big pain, and you should use a volt meter to check that you have the correct wires for positive and negative voltage (the data pins are not used)

We are losing a level of 'isolation' when the sprout is powered by mains voltage, and it is possible to see changes in reactivity and sensitivity between battery and line power.  This is the way which i power my durable installations (1 month+).

Offline pelgrim

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Re: alternative power supplies
« Reply #2 on: August 11, 2016, 08:56:55 AM »

Offline sam

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Re: alternative power supplies
« Reply #3 on: August 13, 2016, 09:13:25 AM »
I wouldn't recommend that particular unit since it is a variable supply.  You only need a 5V power supply (and it can not exceed 5!), you should always measure the true output on a power supply using a volt meter, to ensure it produces the correct voltage and polarity!

This is a better supply, you would just need to cut off the micro usb end and solder on some two pin header.   See if you can find an old phone power supply.
http://www.ohmeron.be/en/voedingen/usb-voedingen/5v-1a-mini-usb-voeding-met-mini-usb-kabel.html

Offline pelgrim

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Re: alternative power supplies
« Reply #4 on: August 13, 2016, 11:55:08 AM »
Went to the hardware store and found more then I was looking for.
The adjustable power supply has only the standard connectors, which don't fit on a pcb.
On insisting I don't like to cut a perfectly well power supply so I can solder it on my board,
I was handed a very handy switch.
This switch has 3 pins, 2 of them (one middle, on on the side) are connected when the power jack is not plugged in,
and they are disconnected when the power jack goes in.
The middle one get's the power from the power jack.

With that information it's easy: connect one (middle pin) to the pcb, the other pin that is interrupted to the battery pack.
The one pin that is free goes to ground on the pcb and battery pack.

Result: when the power supply is not plugged in, the battery pack is giving power to midi sprout.
When the power supply is plugged in, the red wire from the battery pack is interrupted,
and only power from the power jack is used.

On the picture you can see the setup.
I recuperated 2 wires from the bread board kit, they fit very well in the small power socket on the pcb.

Offline pelgrim

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Re: alternative power supplies
« Reply #5 on: August 13, 2016, 11:58:22 AM »
And a close up from that switch

the 128KB limit for attachments proofs to be very small to show details.


Offline sam

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Re: alternative power supplies
« Reply #6 on: August 13, 2016, 01:41:19 PM »
That is great, the barrel connector will be easy to attach to an enclosure.  Just make sure to be super careful about the output on the variable power supply, if you push more than 5v into the sprout the ATMEGA will (at some point) fry.

Sorry about the upload size limit, I don't have very much server space - plus all the zombies posting attachments can crash the site quick!

Offline pelgrim

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Re: alternative power supplies
« Reply #7 on: August 14, 2016, 05:28:18 AM »
So that's the name of that little toy: barrel connector.

I set the output to 4.5 V, as close to the output of the battery pack as possible.
As you can see on the picture, I have a nice range of voltages to choose from,
but I see no reason to choose 5 V, unless you give me one.