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Panda II with Display and Relais (6VDC) on external power


#1

Hi,

I built a project for my Panda II using a 2x16 LCD parallel display. I also use a 6 volt (DC) relais in my project. The external power connector on the Panda II is made for 6 - 9 Volt DC.
I like to connect external power 6 Volt DC to the Panda II power connector. Can I expect issues with my USB? I mean can I connect them both without issues? So, 6 Volt DC to the external connector and the USB plug to my PC.
Is there any information available on the maximum current that my additional components can use via the external power connector on the Panda II?


#2

there’s not much info on current draw for things like the text LCDs. You should assume they draw about the same as a Panda II, depending on backlight etc (yes, they really are that bad). You should be able to find the datasheet that talks about your relay so you can add that in as well.

Typically if you have a 6v 1a (1000ma) power supply, you should be fine.

And there should be no issue running with an external power supply as well as a USB connection.


#3

Thanks for your info. My biggest concern is to destroy my Panda when it is connected to my PC using USB to program and at the same moment the Panda is connected to my external 6VDC power source.
The way I work now is disconnect the shield I made and then load the new code via USB in the Panda, disconnect from USB, connect the shield again and test the program against the hardware on the shield.
It would be easier for me if both connections could be inplace. On the forum I did not find clear answers. Some say it is no problem to have both power sources connected, other say they destroyed their Panda, ohers say it is no problem if the external power source is 5 VDC.
I am a little confused by all the different answers.