No, you should not increase the voltage any further... and at least this answer linked in the question does not suggest to do that.
From Raspberry Pi Power Limitations:
Power sources SHOULD provide 5±0.25V ...
The newer Pi(3/2/B+) have a voltage monitor chip (APX803) which triggers at 4.63±0.07V. The Pi3B+ uses a MxL7704 chip to manage power, ...
The MAXIMUM is 5.25V, although this should NOT be the target. You should not apply more than 5.1V
That is not to say the Pi will be damaged by the higher voltage, because nothing uses 5V - the on-board regulator supplies the voltages used by the Pi. There is a point when the transient protection diode will trigger - causing the poly fuse to blow.
No one ...
I will be customizing another power supply manually using voltage dividers
You can't do that. And this suggests that you're a novice with electronics.
Voltage dividers are fine for signal conditioning or creating a relative reference point for something, e.g. an A/D converter. They are not a way of regulating a power supply.
Any modern computer varies its ...
Nobody can answer that question as it will be down to the peculiarities of the components in each Pi.
As you know 5V +/- 5% (4.75 to 5.25 V) is the USB spec.
In your case I suspect your power supply claims more than it delivers. Try a better cable or known truthful supply.
That said I have powered higher at 5.8V without causing any known damage. However ...
The external hard drive is powering the RPI after you remove the microUSB power supply. This is called Backfeeding.
This is not unusual for raspberry pi's.
Is it bad for the pi
I would advise against backfeeding because there is little protection for the Pi. You would need to ensure there is a stable voltage and current to avoid damage.
I would ...
If the drive is supplying 5V power to the USB port, it will power the Pi. As this is unusual, and not complying with the USB spec, no one can say if it is safe.
NOTE You can not power a Pi through its USB ports, although once booted it will continue to run.
The 2.1A one will be the best. But it may not work and so you should test.
Many power banks and powered hubs are "too smart" (that is, spec compliant, which is good) and will not provide the extended current , above 500mA, without the proper USB PD requirements being satisfied.
In the vanilla case, pre usb pd this was an adhoc "standard" of a resistor ...
If you want an actual button pusher for educational/entertainment needs, then you can ignore this answer.
Given your description, I would assume that this physical button is a normally open push button (NOPB) with two wires going to it. In this case, I would think you could come up with a simpler solution that involves tapping one or both of those wires. ...
Let's take a peek at the Pi 3B schematic. I'll assume you'll use the micro USB input.
Maximum reverse input voltage: 5V
Anything past -5V would probably result in catastrophic failure of the BCM857BS (V_EB absolute maximum rating violation on pins 2 and 1, but then, there are resistors.)
Absolute maximum input voltage without peripherals: 6V (but I wouldn'...
The problem of building a proper power supply for the Raspberry has been discussed at lots of places, and the canonical answer is to buy the official Raspberry power adapter.
I just bought one myself, price was not too high, something like 14 euro, and this includes a contribution to some charitable projects. It is rated 5.1 V and 2 A, and has pretty thick ...
While the other Anwsers are correct as in 'you should not provide any higher voltage then 5.25V', the solution to your initial problem (yellow thunderbolt sign) is to use a power supply which provides a higher current. the official raspberry pi power supply is labeled at 2.5A
And in my experience (running a >100 RasPi research network) a 2A power supply is ...
As you have noted GPIO pins retain their state when shutdown.
There are a couple of exceptions where the state is modified by the shutdown process. gpio-poweroff (which is designed for this purpose) is the most reliable method.
PS RUN and EN pins are INPUTS, and NOT connected to the GPIO. RUN is ...
This howchoo post shows how to connect an LED to show the status of the Pi. The LED is steady on when the Pi is running, and off after shutdown.
Add this line to /boot/config.txt, and reboot
Connect the TxD pin (GPIO pin 8) to the positive lead of a 2 or 3 volt LED.
Connect a ground pin (e.g. GPIO pin 6) to a 330 ohm ...