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The Basic Stamp > interprets instructions in real-time, essentially running a virtual machine on the PIC. This means that it is much slower

The Stamp implements a complete solution on a single PCB. In comparison, a bare PIC requires a separate power regulator and substantial decoupling on its output.

The Gate acts as an antenna, so leave it unconnected.

The 1-meg resistor helps protect the FET from being harmed by any accidental sparks to its Gate lead. The circuit will work fine without this resistor. Just don't intentionally "zap" the Gate wire with a charged object or your charged finger.

To test the circuit, charge up a pen or a comb on your hair, then wave it close to the little "antenna" wire. The LED should go dark. When you remove the electrified pen or comb, the LED should light up again.

If you suspect that humidity is very high, test this by rubbing a balloon or a plastic object upon your arm. If the balloon does not attract your arm hairs, humidity is too high.

This FET sensor is not an ideal educational device because it responds differently to positive than to negative.

negative objects turn the LED off, it lights again when removed. positive objects make the LED bright, then dark when removed.

Obtain a small capacitor with a value below 100 picofarads. Connect it between the FET gate lead and one of the other FET leads (doesn't matter which one.) This greatly reduces the sensitivity of the device

Now make the circuit MORE sensitive. Obtain an alligator clip-lead, and connect it to the Gate lead of the FET. Let it hang loose without touching anything. You'll find that this has vastly increased the sensitivity of your FET circuit.

Li-ion batteries have the same high energy capacity as NiMHs, power output rates of NiCads, and weigh about 20%-35% less. They also have zero memory effect problems, meaning you can recharge whenever

NiCad (Nickel Cadmium) batteries are good for small to medium size range robots. They have the highest current output, are more affordable than NiMH's, and can be recharged within one or two hours

A NiCad, over many charges, can only store less and less energy after each recharge. To prevent memory effect, whenever you wish to recharge your NiCad, you must first fully discharge it.

NiCad batteries contain toxic cadmium stuff, so save a squirrel and recycle/dispose of it properly.

NiMH battaries can last many more cycles than your typical NiCad battery.

they have good current output, and have the highest energy capacity. I would recommend them for small size robots and for powering circuits. Note, NiMH batteries usually take like 10 hours to recharge depending on various factors.

The '240 is often called "the bicore chip," because we can take advantage of the 240's inverters to turn a single 74*240 into a bicore

The '240 also has tri-state outputs, so an enable line can be used to turn its outputs on and off simply (good for adding reversing capability to a 'bot).

any *cores built with a 74*04 will require additional logic "downstream" to amplify the current to levels sufficient to drive a moto

Schmitt triggers can't easily be used in suspended bicore implementations

use its buffers as little current amplifiers

it is usable for either grounded or suspended bicore designs (but better for suspended)

74HC/HCTxx non-buffers (74HC14 or 74HC04) draw about half of the current consumption, and have about half the drive current compared to HC / HCT buffer chips (74HC240 or 74HC245). Non-buffer chips are thus better for oscillators, say Nv and Nu applications; they are not suited for use in driving motors.

74AC is best suited for motor driver applications with all inputs driven rail to rail.

The '245 is an octal buffer chip, and so has 8 channels of buffering power available for our misuse. This chip was designed for data transmission uses, but we'll misuse it as a motor driver chip

The '244 provides us with 8 (thus the "octal") buffers, enableable in banks of 4. This is a very useful chip for amplifying small currents

it can drive up to 4 motors in 2 directions each, or you can "buddy up" inputs and outputs to drive fewer motors at higher current

it can drive up to 4 motors in 2 directions each, or you can "buddy up" inputs and outputs to drive fewer motors at higher current

If you can't find 1381s locally, you might have better luck finding its European cousin, the TC-54 -- for details on it

Note that if you need more than about 200 mA per motor, you'll need to use an H-bridge, or some similar motor driver

The ideal BEAM circuit would use a low (2V-3V) voltage core and sensors combined with level shifting high (5-6V) volt motor drivers to maximize efficiency.

74ACxxx used in typical BEAM applications uses 4x more supply current than does 74HC/HCTxxx.

The monocore capacitor is for positive feedback for fast switching between the two motors and to slow down and avoid high frequency oscillations.

R2 together with C2 limits the maximum frequency of the monocore and motor drivers when the light is bright and the sensors are equally lit

R3 together with C2 sets the minimum frequency of the waggle even in the complete dark which is more interesting than twirling endlessly in a circle.

Having said that, maxibug is not perfect: it churns its wheels while feeding and does not back out of the feeding station when full. CD MaxiBug v5 uses just a few more parts but has powerful and efficient motor drivers, its motors are off while feeding, and it backs up when full.

The CD Maxibug v5 uses just one 74AC240 chip

Place your high current wires away from sensitive areas and antennas.  Don't run the wire parallel with wires that are used as signaling in your micro controller.  If you must its best to have them cross at 90 degrees.

Make sure you get a motor which already has a gear box attached, as it makes your robot much better controlled, more efficient, and stronger.

By default at power-up, the circuit is in coast mode. To brake, set IN A to 0 V, IN B to 0 V, and Q5 to 5 V. To spin clockwise, set IN A to 5 V, IN B to 0 V, and Q5 to 5 V. To spin counterclockwise, set IN A to 0 V, IN B to 5 V, and Q5 to 5 V. At any time you can return to coast by applying 0 V to Q5. Or, you can apply pulses of 0 V/5 V/0 V/5 V (and so on) to control the speed. The more time spent at 5 V, the faster the motor will spin. Whenever you change modes, if you set Q5 to 0 V before making changes to IN A and IN B (and then set Q5 back to 5 V or pulsing) there will be no shoot-through.

the Cricket's green LED light goes on while the Cricket is executing commands.

You can "launch" a procedure directly from the Cricket by pressing the white button on the Cricket.

You can send information from the Motor/Sensor Cricket back to the computer using the send instruction.