Quadcore
From BEAM Robotics Wiki
- A term used when referring to a four Nv neuron based core or nervous network, commonly used as the basis of a 4-legged-2-motor walker
The quadcore, or 4-Nv net, is by far the most-common variant of Nv net. You will sometimes see this circuit referred to as the Microcore, which is the quadcore topology with accompanying sensors and peripheral circuitry.
In its "natural state," a quadcore will, at power-up, be saturated with 2 processes active) -- here, the active inverter(s) are highlighted:
In most cases, though, this won't be what you desire -- you'll generally just want a single active process running:
Since 4 neurons will enable you to drive two motors in both directions, the most-common use for a quadcore circuit is as the motivating force behind a 2-motor walker. While I've got more information on this use elsewhere, here's an animation showing how this layout works (motor directions are arbitrarily shown by red or green):
Note that in order to build a device on the basis of a quadcore, you need to use Schmitt inverters (since a Schmitt's hysteresis ensures a clean transition). As a result, quadcore circuits will generally be built up from 74*14 or 40106 ICs. The same thing holds for more-complex non-suspended microcore variants -- quintcores, hexcores, and the like.
In a 74HC14 microcore, the Schmitt input guarantees a single output transition when a Nv switches, which keeps it out of saturation. On the other hand, a microcore (or 6 Nv or 8 Nv core) made with "vanilla" 74*240 inverters will also "work" but will quickly saturate from noise picked up in the transition region.
