Off-road mobile robot at http://robot.proof.cz

Hi guys,
I'd like to show you my mobile robot based on the HandyBoard controller. Pls have a look at http://robot.proof.cz
Basic info: * 2 MHz microprocessor Motorola 68HC11. * 32 kB RAM, battery backed. * Drives up to 4 DC motors. I've changed the two L293D circuits with four SN754410NE so I can now control DC motors with up to 2A constant or 2.4A peak power consumption. (See H-bridges) * Two motor outputs can be used to control a stepper motor. * 16 x 2 LCD display. * Two fully programmable buttons, potentiometer with 0-255 range and a piezo buzzer. * 7 analog and 9 digital inputs. All of them powered for use with active sensors. * 9.6V NiCd battery pack. Charging is done by a special interface adapter or directly using the main board. Just connect a power adapter and that's it. * A 38kHz infra red receiver/transmitter. It's not connected at the moment, I'm working on a remote digital radio control. * 8 pin powered serial connector interface with up to 1 Mbaud transmission speed. * Easily expandable using the expansion board.
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On Feb 1, 6:04 am, snipped-for-privacy@gmail.com wrote:

If the motor needed smooth DC , you must use "H" bridge . Switch mode circuits are more powerful . You need only low cose bipolar transistors and a little bit of inductor . coils close to the value of the motors inductance will work . These self oscillating bipolar circuits will rise 10 amps into a motor in milliseconds . You only need to turn them off , they turn on by themselves . One circuit to drive the ground based motor , positive and another to drive it negative .
This circuit is far more fault tolerant and easier to control .
I cant understand why colleges dont teach these better methods . But i know why i left college after half a semester ! The proof is in commercial stuff like low cost power supplies . They only use 1) single bipolar , 2) self oscillating , 3) switch mode , "forward" converters, not fly backs .
I think its clever to nix the always present problem of driving the 1 vdc base of a bipolar . Its just a 2nd winding on the core ! Now i can fully saturate it for 90% efficiency , unlike your H bridge that needs a very large heat sink !
If your friends explain a complicated I.C. controlled "switcher" , it is NOT what im talking about .
Single bipolar , self-oscillating , and stopped by the simplist .03 amp control .
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