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Note that the resistor value of the pull-down resistor affects the voltage at pin 3 of the Furby's connector. We used a 1k ohm resistor to make it less sensitive to light (since we're now operating with it open to ambient light).

In the above diagram, a 20k ohm resistor is used as the pull-up resistor. You can, however, use any resistor as the pull-up resistor as long as the resistance is high enough to protect the circuit.

Motorcycle lead acid batteries work great for larger low performance type robots. They are great for solar power robots too.

lead acid batteries have the serious problem of being very large and heavy, need to always be kept charged, and do not have the high discharge rates as the more modern batteries.

They have low power capacities, are heavy, have trouble supplying large amounts of current in short time periods, and get expensive to constantly replace

robot learning

variable delay

short-term memory

By just tying a neuron's bias resistor to Vcc, rather than to ground, you can make a "regular logic" (active high) Nv:

putting diodes and other resistors in parallel to give different charge vs. discharge rates

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One essential difference is that the Nv responds immediately to an input, and sends the output for a time duration -- the delay occurs AFTER the output is sent. The Nu responds to an input after a delay and sends the output continuously -- the delay occurs BEFORE the output is sent.

"on" first, then a delay, then "off"

delay, then "on", stays "on"

34164s are undervoltage sensing circuits ("voltage supervisors") designed for use as reset controllers in portable microprocessor based systems. We use them as 3- or 5-volt triggers (here, 3 or 5 fills in the "*" of the part number above), as the heart of the Chloroplast solar engine design.

A device used to store charge in an electrical circuit. A capacitor functions much like a battery, but charges and discharges much more efficiently

BEAM robots tend to use capacitors in two, very different roles -- small ones in Nv neurons and solar engines (filter capacitors), and bigger ones as energy storage devices (storage capacitors).

Reverse bias induces only little current (known as saturation or back current) along its direction. But a more important effect of reverse bias is widening of the depletion layer (therefore expanding the reaction volume) and strengthening the photocurrent. Circuits based on this effect are more sensitive to light than ones based on the photovoltaic effect and also tend to have lower capacitance, which improves the speed of their time response. On the other hand, the photovoltaic mode tends to exhibit less electronic noise.

Photodiodes can be used under either zero bias (photovoltaic mode) or reverse bias (photoconductive mode)

The BASIC Stamp is a microcontroller with a small, specialized BASIC interpreter (PBASIC) built into ROM.

The third variant is the Javelin stamp. This stamp uses Sun Microsystem's Java programing language instead of Parallax's PBasic

all current PICs are Flash-based, and support in-circuit programming.

We assume that the slowly changing waveform at the Nv input produces a single output transition when it crosses the Nv switching threshold. This is accomplished by using a 74HC14 or similar CMOS Schmitt trigger. When 74HC04 or 74HC240s are used for Nv inverters some nasty oscillations occur during switching which makes these inverters unsuitable for most Nv networks greater than 2 Nv in series.