trying to power an Arduino uno that has a servo moving back and forth with a power bank. I have tried 3 different but all shut off when connected to Arduino after about a minute. Any suggestions? (they work on a phone)
P.S if you're interested its to swing a clock arm in a musical
The power banks are for low current devices. Use AA battery packs or LiPo with a BMS.
What is the power bank voltage?
What Uno pins do you use to connect the power bank to?
You can look here for some tricks to subvert the auto-shutoff feature of some power banks: Powering the arduino nano with a Power bank - #10 by 6v6gt
Old school. I love it.
You can also do the same thing with a relatively high current load switched on and off form an output on the microprocessor.
Like a resistor and a transistor switch, turn it on briefly on the necessary interval.
In @6v6gt's '555 circuit, the PNP and 47 ohm resistor. If that were all you added to the rest of the project, I'd use an NPN transistor.
I don't have the equations for frequency and duty cycle of the '555 memorized. Presumably the component values could be used to see what was used in this case.
It may need some adjustment.
I solved it by simply always drawing enough current, but I wasn't leaving something in the woods to live as long as possible; power banks make nice desktop source of 5 volts USB, and with a bit of hacking, 5 volts on red and black wires for whatever.
a7
That makes me wonder about USB-C and if some power bricks have a connection state machine that might be coaxed into doing something useful.
Well it's often the case that when I review an old design of mine, I think initially to myself "what idiot threw that together". In this case, however, there was valid reason for the choice of a PNP transistor. The output of the 555 in astable mode always has 50% or greater duty cycle (simplest configuration) so I inverted it using an PNP transistor to achieve a 1% duty cycle.
The circuit is also a bit "heavy weight" because it had test bed character, allowing me to try a few values, and I had no idea what to expect.
TBC I knew there would have been. I've forgotten more than I ever knew about the '555, but I do seem to recall having to deal with its output functionality differently than I might have liked to do.
I still have things using '555s been running for, uh oh, decades.
Last thing I did with one was a spoofer for a garage door opener safety system. The one I deployed, however, was tucked into a microprocessor that was doing a bunch of other stuff and had some resources available.
One thing for sure, way easier to set frequency and duty cycle with software.
a7
As you didn't post the wiring of your project, tell me how Are you connecting the +V and Gnd of your servo, to the Arduino or to your power bank? Remember that the Arduino is not a power supply.
You've already bought your powerbank, but future readers should note that you can get modules for 18650 cells that work like powerbanks, but without the low-current shutdown.
https://forum.arduino.cc/t/at-last-18650-charge-boost-module-with-load-sharing/1164462