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[SOLVED] Prevent powerbank to go into standby mode

Posted: Fri Sep 11, 2020 12:24 pm
by vince
Hi Everybody!

I have a simple question concerning the pyboard. I want to use it with an external powerbank. It works fine, but the pyboard is just too efficient :mrgreen: and not drawing enough power, so the powerbank thinks it is not used and goes into standby mode after 30 sec (and switch off the pyboard). :roll:

What could I do to draw more power?

1. I read on an arduino forum, to connect a 470 Ohm resistor from voltage to GND. Is this safe? If yes, should I use 3V3 or V+? The pyboard is out of stock and I really don't want to break it.

2. Or should I prefer doing some silly calculations in the background to increase cpu load?

Thanks in advance,

Vince

UPDATE: I'm using a pyboard V1.1, the powerbank is an Intenso Powerbank XS10000

Re: Prevent powerbank to go into standby mode

Posted: Fri Sep 11, 2020 2:48 pm
by chuckbook
It's usually ok to create power peaks onec and a while to keep the power bank happy.

Code: Select all

def wup(p):                                                                                                        
    for i in range(1000):
        pass

rtc.wakeup(10000, wup)
This is a pretty naive way to create power consumption peaks, but it shows the idea.

Note:
If you run your pyboard at a low processor clock it might not reach an adequate power level to keep your power bank happy.

Re: Prevent powerbank to go into standby mode

Posted: Fri Sep 11, 2020 4:16 pm
by pythoncoder
I have encountered that one. The amount of current you need to draw depends on the design of the powerbank. You haven't said what type of Pyboard you have but on the assumption that it's a V1.0, V1.1 or Pyboard Lite the V+ pin is connected to USB 5V through a diode so you can safely draw power from there. I use 100Ω to draw just under 50mA. If that isn't enough, try 47Ω.

Re: Prevent powerbank to go into standby mode

Posted: Fri Sep 11, 2020 4:48 pm
by vince
Hi pythoncoder,

your solution worked! :D Thank you very much.

First I tried with 100Ohm, but it didn't work. Then I tried with 50Ohm (5x10Ohm), and this worked!
I will buy a ~50Ohm resistor asap and try again.

Re: Prevent powerbank to go into standby mode

Posted: Sat Sep 12, 2020 12:23 pm
by pythoncoder
I should point out that the 50Ω (or 47Ω) resistor should be rated at 0.5W or above.