Reddit reviews Universal AC Adapter, ZOZO 12W 3V 4.5V 5V 6V 7.5V 9V 12V Regulated Multi Voltage Switching Replacement Power Supply for Household Electronics Routers Speakers CCTV Cameras Smart Phone USB

The power supply for the HMD is rated at 12 volts, 1.5 amps. This "ZOZO" adapter from Amazon should work fine. I just checked my Vive HMD power supply with a meter and the polarity is "inner Positive(+), outer Negative(-)", just like in the Zozo description, so polarity won't be a problem. Just pick out the plug adapter that fits from the assortment they give you and set the voltage to 12 volts.

Edit: The $10.98 unit is rated at 12 watts, which is only 1 amp at 12 volts, so the current rating of that unit is lower that the original power supply. Maybe you'd better get the 36 watt unit for $14.99, just in case. That unit should be good for 3 amps, which means double the rated capacity of the original supply.

Amazon has a lot of other choices as well. Just look for 12 volt capability at at least 1.5 amps (or 18 watts), the correct polarity, and an assortment of plug adapters so that you'll get one that fits.

Different size barrels, yes, but those multi-output adapters usually have a switch that picks what voltage it actually puts out. I've seen a bare few which have the voltage setting as part of the tip, but almost none do that because the form factor is typically not related to the voltage at all. (Well, larger does tend to go with higher voltage, but there's no standard for this at all.)

Random example: https://www.amazon.com/Regulated-Switching-Replacement-Household-Electronics/dp/B015PXUHYA/

Though most I'm seeing now seem to use rotating switches; they used to all use a flat sliding one, heh.

I usually just recycle an old DC power adapter. The math is really easy. Count the A* batteries and multiply by 1.5 to get voltage.

If you wanna be really fancy, get a bunch of these: https://www.amazon.com/ZOZO-Regulated-Switching-Replacement-Electronics/dp/B015PXUHYA/

In technical terms, converter means AC --> DC. Inverters are DC --> AC. Converters can also refer to voltage adjustments like you are saying (AC to AC converter, or DC to DC converter). There's no such thing as an AC to DC inverter, although many people misuse the term.

The little box that you plug between your laptop and the wall is a converter.

I have a little wall wart universal converter that you can flip a little switch the voltages on, like this one.

It looks like just a regular AC wall charger. This thing has tons of attachments and one will definitely fit!

ZOZO 12W 3V 4.5V 5V 6V 7.5V 9V 12V Regulated Multi Voltage Switching Replacement Power AC Adapter for Household Electronics Routers Speakers CCTV Cameras Smart Phone USB Charging Devices

https://www.amazon.com/dp/B015PXUHYA/ref=cm_sw_r_cp_api_i_733.Ab75XZ3PX

Usually called a barrel or coaxial plug. Somewhere on the label or in the manual it should tell you what voltage and amperage you'll need.

Something like this MAY work, but you need to know the voltage and amperage needed first to make sure that replacement cord will be enough.

What game console is it? Someone can generally tell you what you need with that info.

This will work as long as the tip fits

ZOZO 12W 3V 4.5V 5V 6V 7.5V 9V 12V Regulated Multi Voltage Switching Replacement Power Universal AC Adapter for Household Electronics Routers Speakers CCTV Cameras Smart Phone USB Charging Devices https://www.amazon.com/dp/B015PXUHYA/ref=cm_sw_r_cp_apa_i_VHDODbZ20QTVC

Just note it is center negative! (Most are center positive, so for
this you need to make sure the tip is set to the - side not the +)

Edit corrected link

Edit, this one too
[Inner Negative] SoulBay 3V 4.5V 5V 6V 7.5V 9V 12V Multi Voltage AC/DC Adapter Switching Replacement Power Supply with 6 Plugs for Household Electronics Tip Negative Effects Pedals Keyboards - 2A Max https://www.amazon.com/dp/B07GVFKKPR/ref=cm_sw_r_cp_apa_i_jJDODbRN4WHE7

I have a similar motor shield. you need a power supply. especially if you are running just 3v instead of the 5 for the Arduino.

you need to know the rating of your Servo/ stepper motors and provide the power for that. for example I supplied I think it was around 1.8 amps at 2.2 volts or something for mine.
if I were you I would get something that provides different voltages like a universal like : https://www.amazon.com/Regulated-Switching-Replacement-Household-Electronics/dp/B015PXUHYA/ref=sr_1_1?ie=UTF8&qid=1486910848&sr=8-1&keywords=universal+power+supply

it will make testing and compatible with other project.

if those are the only connections, you don't appear to have any MIDI output. that might be an issue, but i'm not familiar with the software you want to use.

if you'd care to post the make and model of your keyboard, i can try to look up the manual to figure out exactly what power supply you need. if you don't want to do that, then here's what you could try instead:

from the picture, you definitely need a DC power supply with a center positive barrel connector. does it say "DC 9.5V" on there? if so, i (personally) would try a 9V power supply with it. that's 99% sure to be safe, and 98% likely to work.

find something like https://www.amazon.com/ZOZO-Regulated-Switching-Replacement-Electronics/dp/B015PXUHYA/ for your country, and set it to 9V, make sure to read any instructions so that it is definitely center positive when you plug it in, and then give it a go. if it doesn't seem to work within the first 30-60 seconds, don't leave it plugged in.

Having a few different version of these around you don't need to worry about splicing. They come in handy.

https://amzn.com/B015PXUHYA

If you still have the original proprietary charger, it has information printed on the adapter that listed the voltage and amps. It should also list if it's a positive tip or a negative tip symbol.

With that information you should be able to use something like this and get it to work.

As long as it's not the physical port in the Nook that has worn out. Unfortunately, plugging and unplugging flexes the solder connections and eventually they wear out. Since the Nook probably has the connector soldered directly to the mainboard, it won't be possible to "repair" it.

It definitely matters which side is positive or negative. If the plus is attached to the dot in the middle of the circle, it's center-positive. If the minus is attached to the dot in the middle, it's center-negative. If you hook it up to the wrong supply, it can damage the equipment (think putting the gas in your car's tailpipe instead of the tank filler).

You can buy replacement supplies that come with multiple tips. Just make sure you get one with enough amperage/wattage to power the amp. Near where the center positive/negative diagram it should say something like 9VDC 1200ma or 9VDC 3.1w. That means you need a supply that puts out 1200 milliamps, or 3.1 watts.

A universal supply looks like this: https://www.amazon.com/Regulated-Switching-Replacement-Household-Electronics/dp/B015PXUHYA/ref=sr_1_2?s=electronics&ie=UTF8&qid=1482438995&sr=1-2&keywords=universal+dc+power+supply

This power supply works well:
https://www.amazon.com/ZOZO-Regulated-Switching-Replacement-Electronics/dp/B015PXUHYA/ref=mp_s_a_1_1?keywords=zozo+12w+3v+4.5v+5v+6v+7.5v+9v+12v+regulated+multi+voltage&qid=1570668960&sprefix=zozo+12&sr=8-1

This works perfectly for the Connect/Commander connection cable:
https://www.amazon.com/Green-utech-Ft232rl-Ttl-232r-5v-aj-Programming-Windows7/dp/B00XSOELNW/ref=mp_s_a_1_fkmr0_2?keywords=green-utech+ft232&qid=1570669266&sr=8-2-fkmr0

In that photo, the 9V is providing power to the Arduino and the AAs are providing power to the servos, or whatever that box is powering. For your setup, you can power the Arduino via USB like you're doing, and then power the servos with a 6V power supply. You can either buy a power supply on Amazon (this one is universal, so be sure to select the 6V setting when you use it) or you can go to a Goodwill and find a power supply that outputs 6V (and at least 1.5A). If you go the latter route, be sure to test the voltage first. You'll need to cut off the end of the cable and put the power wires into the breadboard. As long as the power supply can output at least 1.5A (roughly 4x the stall current of the servos) you'll be able to run them all in parallel.

Edit: To clarify: Get some sort of 6V power supply, take apart the cable, and put the positive and negative wires in the same spots you have your 4xAA battery right now.

For future reference, unless you need something to be portable or want it to survive a power outage, there's no reason to use batteries instead of an outlet.

You could get a universal power adapter like this.
https://www.amazon.com/ZOZO-Regulated-Switching-Replacement-Electronics/dp/B015PXUHYA

Most electronic stores should have some version of this with different sizes of interchangeable barrel plugs.

actually, what i think i might do is get this:
https://smile.amazon.com/ZOZO-Regulated-Switching-Replacement-Electronics/dp/B015PXUHYA/ref=sr_1_3?s=electronics&ie=UTF8&qid=1540834898&sr=1-3&keywords=6v+dc+power+adapter

which will allow me to use the adapter/spacers in different items that would have more/less aa batteries.

Would having one of these for each string be enough? then a separate power for the board?

The PAL SNES power supply actually outputs AC and not DC. However, the console will still accept DC inout, since the AC is being converted internally anyway.
You need it to be 9V, and at least 1.3A (according to spec, it might be less). Your first link doesn't have enough amps, and the second one doesn't seem to have the information. The polarity doesn't matter since it's expects AC anyway.
The tip needs to fit in the plug, so you might want to get a universal power supply to be sure. I quick search led me to this one (which is 12W, which means that at 9V it is: 12/9=1.33A):
https://www.amazon.com/ZOZO-Universal-Regulated-Replacement-Electronics/dp/B015PXUHYA/ref=sr_1_1?ie=UTF8&qid=1468583528&sr=8-1&keywords=9v+power+supply+universal
(there might be other ones on amazon that are cheaper, I just sorted by relevance.)
And it seems that tip1 will fit. (outer diameter 5.5mm inner diameter 2.5mm). (you might want to make sure this is correct).
If you have other consoles at home, it is also possible that you can use one of their supplies, though I don't think the NES barrel will fit, and it's a little low on amps, so it might get too hot and die.
EDIT:
I've just seen that the power supply I've found doesn't have the option to choose polarity. It doesn't matter in your case, but it's pretty sucky if you wanna use it for other stuff.

Buy this and start with the lowest setting, just dialing it up until it kicks on. if it works, but cuts out during use, just dial it to the next setting. It will probably be 9 or 12 volts, possibly 16.

ZOZO 12W 3V 4.5V 5V 6V 7.5V 9V 12V Regulated Multi Voltage Switching Replacement Power Universal AC Adapter for Household Electronics Routers Speakers CCTV Cameras Smart Phone USB Charging Devices https://www.amazon.com/dp/B015PXUHYA/ref=cm_sw_r_sms_apa_i_w3slDbQY6MSRK