3.5
Powering the board from the USB port
In some applications, you may find it convenient to power the QLG2 board from the USB
port.
In this case, simply solder a jumper wire across JP11 as shown in the diagram below.
Tip
: I am in the habit of making my soldered jumper wires as a little loop, standing up about
5mm from the board surface; this is because even if I am 100% sure now, that this will be a
permanent connection… all too often I find for whatever reason, I will change my mind later.
To make it easier to remove, or to temporarily disable, a jumper wire – I just make a 5mm-
high loop rather than a wire laying near the PCB surface.
The 5mm loop is a lot easier to
cut and if necessary, to remove, than a wire tight flat against the board surface.
If you already feel now that it will not necessarily be a
permanent connection, then fit a 2-way pin-header
and use a header jumper, as pictured (right).
Now you might be thinking, “I have pin headers, but I
don’t have those fancy jumpers you used to find (and
maybe still do) on old PC Motherboards, and I don’t
fancy waiting for Amazon, eBay, whoever”… well
never fear, for necessity is the Mother of invention – I
don’t have those fancy jumper plugs either, I just
improvise using female pin header connectors. Which
aren’t even the right right size (2-way) but can be cut
to leave just two pins… and then gently bend over the
two pins towards each other and solder in the middle
(see photo, right).
IMPORTANT: never connect the jumper to power
from USB, and at the same time 5V power
from some other source to the other connection
pads! NEVER, EVER!
QLG2 manual for firmware 1.00a
10
