Version 1.6 - May 28, 2012
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terminal and not chain the negative connection from unit to unit. However, if the two or more
MegaMoto units are stacked on an Arduino it is acceptable to chain from one unit to the next
as long as a good connection is made to each unit and the wire is of sufficient size to cause
negligible voltage drop at the load current. When in doubt fatter and shorter wires are better.
Further if two different voltage sources (batteries or power supplies) are used, say one to
power the Arduino and one to power the MegaMoto, it is imperative that the connection
between the negative terminals of the voltage source be lower impedance than that between
the Arduino and the MegaMoto. This is to prevent a ground loop between the Arduino and
MegaMoto, which can destroy either unit. See Figure 7 for an illustration of this. If the
Arduino is powered by a USB connection it is not necessary to provide this negative-to-
negative connection as the USB ports are protected against such faults.
Figure 7. MegaMoto and Arduino connected to different batteries