manually turning ledborg
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Hello,
i am going to use the ledborg in two projects. In one of them, it is going to be in a solar powered device used to monitor c02 and c0. Ssince it is going to be solar power, i dont want to have it on all the time. I would love to be able to have the ledborg off all the time unless a user toggles a manual switch, in which case i want the ledborg to operate normally.
I was thinking of having the ledborg not attach directly to the pi but on a separate circuit board and put an inline switch (like a toggle switch) connect the board to the pi using a ribbon and then put an inline switch on the 5v line.
how does that sounds to you? DO i need any resistors? Any suggestions on how to accomplish this?
Thanks
PS And a lot of appreciation for all the support to my previous questions :)
piborg
Mon, 09/08/2014 - 10:10
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Connecting LedBorg via a power switch
Put simply it is unlikely you can make this work in a simple fashion.
The problem is that LedBorg has a capacitor fitted which helps prevent noise from switching LEDs on and off, which in turn could cause a drop on the 5V line.
The reason for this is that the Raspberry Pi expects a stable 5V line, in the event of a drop it will likely cause the Raspberry Pi to reboot.
The reason this is a problem is that by disconnecting and connecting the 5V line you are disconnecting and connecting this capacitor.
When this happens the capacitor causes such a drop instead of preventing it.
I would suggest attaching a button to a free GPIO pin as shown here:
http://elinux.org/RPi_GPIO_Interface_Circuits#Buttons_and_switches
you can then use Pi4J to detect changes in button state:
http://pi4j.com/usage.html#Listen_for_Pin_Changes
and turn the LedBorg off in software when not needed.