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Adding a capacitor between Vcc and GND
#1
Lightbulb 
Okay, I have deleted my post about GPIO charging, I got impatient and simly risked it, YES, it does support GPIO charging Big Grin

But it did not really fix my problem, as our home power grid is suffering from micro voltage drops. It's something that all electronics we use can counter with ease, except the tinker board...

My question is; can I connect a capacitor between the Vcc and GND pins on the GPIO to act as a very crude voltage protection "circuit"?
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#2
(08-30-2017, 05:09 PM)Derek Wrote: Okay, I have deleted my post about GPIO charging, I got impatient and simly risked it, YES, it does support GPIO charging Big Grin

But it did not really fix my problem, as our home power grid is suffering from micro voltage drops. It's something that all electronics we use can counter with ease, except the tinker board...

My question is; can I connect a capacitor between the Vcc and GND pins on the GPIO to act as a very crude voltage protection "circuit"?

On a RPI forum, I saw a project using 10000uF capacitor for protecting micro voltage drops. They connect it directly between GPIO 5V and GND.
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#3
(09-01-2017, 08:27 AM)JGX Wrote: On a RPI forum, I saw a project using 10000uF capacitor for protecting micro voltage drops. They connect it directly between GPIO 5V and GND.

You propably don't have a link anymore, do you?
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#4
https://www.raspberrypi.org/forums/viewt...hp?t=26993
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#5
(09-01-2017, 06:09 PM)Derek Wrote:
(09-01-2017, 08:27 AM)JGX Wrote: On a RPI forum, I saw a project using 10000uF capacitor for protecting micro voltage drops. They connect it directly between GPIO 5V and GND.

You propably don't have a link anymore, do you?

Unfortunately no, it was long time ago.
Sorry
However, rpi still works with 4volts and drains around 700mA, let's take 1A as the TB is more comsuming.
For 10ms power loss protection in those conditions, a 10000uF should work
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#6
Hi All,
I tried to install a capacitor to check if it worked.
As I had in stock a supercapacitor of 5F@5V, I installed it to see what happened...and it does not work.
FYI, I tried it with Android OS.
DC power inlet is plugged on GPIO pins.


With HDMI screen, it boots correctly but as soon as you unplug the power inlet the TB stops while the voltmeter shows 4.78V. Please note that if you plug a 4.8V inlet, the TB starts normally...

With RPI touchscreen, you cannot even boot. The screen "Rockship kernel" is displayed, fades to a white screen and appears again. This sequence is running in loop.

Please also note that I tried this bearboard assembly with an RPI3...and it works perfectly!! With 5F you evven have time enough to proceed to a clean shutdown with your mouse without stress.

I guess TB has some DC input survey system.
Till now, I grabbed no info regarding this.
@Asus specialists, how can we proceed to install a back up (or filtering) DC input?
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#7
See the link I posted above.
It should work with a relay which can switch between
A power supply and a backup battery.
I.e capacitor should keep it running in the millesconds
It takes for relay to switch
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#8
(09-14-2017, 08:36 AM)Z80 Wrote: See the link I posted above.
It should work with a relay which can switch between
A power supply and a backup battery.
I.e capacitor should keep it running in the millesconds
It takes for relay to switch

Actually, it works with a RPI3, I tested it.
But not with the Tinker Board, and even worse when connected with official RPI 7" touchscreen.

As soon as some component is connected on the DC input line, the TB does not finish the boot session and reboot again and again.
There must be some input current detection on the TB or something very sensitive.
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