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Topic: Arduino Yun with batteries (Read 17462 times) previous topic - next topic

ShapeShifter

The load draws the needed current from the supply, up to the limit of the supply. The power supply does not force current into the load. You always want the current rating of the power supply to be higher than the power needs of the load.

You should be good with a 1A supply. The real question is how well regulated is the supply, and how clean is the power?

cipri92

This is how it looks like: http://bit.ly/1LiGuFJ

I read on the Yun's guide page that it can be powered through it's 5V and Vin pins. What's with the "and" in the sentence?

ShapeShifter

Can't tell anything from the picture, it's the specifications that count. And you usually don't get any that are meaningful when looking at an inexpensive supply.

I think "and" is wrong. To power the Yun, you use either the USB port, or you feed regulated 5 Volts into the VIN pin. On the Yun, 5V is an output only. You can't feed power in that pin because there is a diode that prevents current from going in that pin. (Actually, it's more like 4.5 Volts out because of a diode drop on the VIN pin and another on the 5V pin.)

Most other Arduinos can accept higher regulated voltages on the VIN pin, or regulated 5 Volts in on the 5V pin. If you feed power in VIN, you can also use 5V as a regulated power output. But the Yun is quite different in that regard and the same power rules don't apply.

cipri92

#18
Feb 20, 2015, 11:23 pm Last Edit: Feb 21, 2015, 12:12 am by cipri92
Here's the datasheet of an 8 pin IC on the supply: http://bit.ly/1Bw36R8

The supply outputs 5V +/- 0.2V. That means it can go up to 5.2V.

The 32U4 on the board can take up to 5.5V. Am I still on the safe side even though it's possible the supply doesn't have a regulated output?

ShapeShifter

#19
Feb 21, 2015, 12:14 am Last Edit: Feb 21, 2015, 12:14 am by ShapeShifter
It's more of a case of the whole circuit that determines things like stability, noise rejection, ripple, etc. I'm sure you'll be OK with it, it looks to have a lot of filtering capacitance and reasonable construction. The picture doesn't really raise any red flags in my mind, unless the board is really cheaply priced.

cipri92

#20
Feb 21, 2015, 12:22 am Last Edit: Feb 21, 2015, 12:27 am by cipri92
I paid arround 4 USD for it.

Here's the link. It's the 5V 1A supply.

sdesalas

#21
Oct 29, 2016, 12:31 pm Last Edit: Oct 29, 2016, 12:58 pm by sdesalas
4 x new AA NIMH batteries seem to work fine for me.  :)  :)  :)

They were at 5.07 V when fully charged, then hover around 4.8 V when discharging, all well within standard USB thresholds.

I checked amperage and I could draw around 2-3A in short bursts and the Yun consumes around 0.3-0.5 amps normally. I havent run them through to discharge but estimate that I should be able to get around 8hours or so based on what other people are posting here.

Make sure you plug the + into the Vin input (5V did not work for me). I would also advice against plugging in high EM inteferance devices such as Servos and DC motors to the circuit.


ShapeShifter

Make sure you plug the + into the Vin input (5V did not work for me).
Yes, that is an important difference from the typical Arduino, which takes in unregulated voltage on the VIN pin, and where the 5V pin is either a regulated voltage out or regulated voltage in.

By comparison, the VIN pin on the Yun is a 5V regulated voltage input - if you put a higher voltage on this pin like you would with any other Arduino, you will likely damage your Yun. And the 5V pin on the Yun is strictly a voltage output pin - there is a reverse polarity diode that prevents feeding any sort of power into this pin.

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