Slipknot Turbot Circuit Description

The Nervous Net is comprised of six Nv Neurons on a 74AC14 Schmitt inverter chip. We have added an indicator LED for each Nv, as well as two switches. These are for observing the Nv Net patterns and influencing the patterns directly.

Nv(5, 6) and Nv(9, 8) form a sensor Bicore. The brighter the light, the faster it oscillates. This could be a problem in too bright of light, causing the Bicore to be dazzled or locked up. R3 prevents the “dazzle condition” by setting a minimum oscillation period.

The sensor Bicore is a hybrid grounded (R to Gnd) and suspended (R connected) Bicore. Suspended Bicores built with Schmitt inverters must differ by at least double RC in order to oscillate. Since the sensor Bicore may perform as a suspended Bicore, Nv(5, 6) has a 0.1uF capacitor for about 1/2 the capacitance of Nv(9, 8).

The motor Quadcore is formed by Nv(1, 2), Nv(13, 12), Nv(3, 4), and Nv(11, 10). The RC timeout on these Nvs is enough to move the flagellum about a quarter of one rotation. Clearly, the Turbot would not flip if the motor Quadcore was left alone.

The sensor Bicore both strengthens and neutralizes pulses in the motor Quadcore. Nv(9, 8) biases Nv(11, 10) through R1 to increase or decrease the pulse duration. In addition, Nv(9, 8) cancels pulses via a diode on Nv(3, 4). The Nv and diode function as a Pulse Neutralization Circuit (PNC). Nv(5, 6) biases Nv(3, 4) through R1 and connects to the PNC diode on Nv(13, 12). The two PNC diodes keep the motor Quadcore from saturating (e.g. running multiple pulses).

With the R1 and R2 in the M-Ohm range, the sensor Bicore will act upon existing pulses within the motor Quadcore. This can be observed by using the switches to trigger the PNC diodes. No new pulses will start in manually neutralizing Quadcore. By contrast, the sensor Bicore creates new pulses in the Quadcore when either R1 or R2 is in the k-Ohm range. You can remove the pulses and yet the Quadcore restarts.

The influence of the sensor Bicore on the Quadcore enables the Turbot to tumble. The longer the pulse on Nv(5,6), the longer the pulse on Nv(3, 4), thus lengthening the rotation of the flagellum from 1/8 to as much as two or more. Likewise, the longer the pulse on Nv(9, 8), the longer the pulse on Nv(11, 10).

A 74AC245 motor driver supports the Nervous Net. The 0.1 uF capacitors are for noise suppression. The more noise there is, the shorter the pulses, and thus the Turbot may not be able to flip over and move about. For the purposes of experimenting, we added a switch to disable the 74AC245. The green indicator LED lights when there is power and the '245 is enabled.

The power supply is two 4.8V NiCAD cells in parallel. To charge these batteries, we have added an onboard battery charger. The circuit is from the Solarbotics BEP kit (BEP-25cChg). The red LED indicates that the batteries are charging.