Good morning Roy..
at first my intention was to use OP Amps like LM 320 , and switching ICs like ULN 2004.. but later decided to go with simpler circuits, that mostly using simplest transistor based.. and first i tried with PWM based circuits.. but found so powerful even at low throttle levels.. so, here i need some soft controls possible.. so turned to DC basics.. the start up circuit is based on a Darlington pair transistor, that i made of BC 548X2.. its sure, can only drive milli amps.. so, by connecting a high bright LED, at collector, it works when we apply a bias at base.. so, here, i added a capacitor, along with three 100 K resistor network, at base biasing line.. so, when we apply power supply, the transistor only conduct, after fully charging the capacitor.. when the capacitor is fully charged, the voltage across the base increases gradually, and still that can be controlled by the preset.. so, the LED starts to glow, after a certain time, that depends upon the value, of the capacitor, then start to glow slowly, in to full brightness.. in a very soft manner.. so, the first drive circuit is done.. we have a soft start up circuit.. then i made a second darlington pair, based on SL 100 and TIP 3055.. and for biasing the base, i added an L D R, along with a preset, that sealed along with the L E D of the first circuit.. this arrangement gave me a dramatic result.. the motor connected at emitter of TIP 3055 starts so softly, and can adjust further with presets.. so, when we apply power, the motor still stands dead to a certain time, that can be from 2 seconds to any length, then starts so softly, then in to full power, taking almost 5 to 6 seconds.. to brake the motor, we can short the leads of the capacitor, on first circuit, so it blocks the base biasing of the first transistor set.. once again, the motor stops, waits.. and starts again so softly.. by adding a capacitor, to the L D R , we can add soft braking also, because, even after cutting the power from first circuit, the capacitor, provides voltage to the base, of SL 100, holds motor for little more time and stops gradually, as the capacitor discharges.. so, it stops so softly.. to get hard, we can go without capacitor..
now, we need only a timing circuit.. that is based on NE 555 that you can get ample of circuit from Google.. so, when the set time is reached, the relay energize, or de energize, activating the circuit, so motor starts to run.. and when the relay is again, the motor stops, and starts softly to opposite direction.. for braking, we can add a switch, that shorts the capacitor.. so motor never starts again..
while adding a potentiometer at base biasing of the SL 100, we can add a simple throttle control..
we can also fix this motor driving circuit, without timing circuit, instead can add relays, and leaf switches, that means you have to wire two each wires, at each ends of the track.. so, when the switch is pressed, one relay (DPDT), energizes, and holds there, as we connect the lead through one set of the relay contact.. so the relay will energized until we releases the power supply.. so, we can connect the other set of relays to the next contact set of the same relay, for adding motor drive circuit.. so the train run FOR and REV on its own.. can also add station stop switches at each station, that momentarily shortens the capacitor.. so the train stops.. then starts slowly.. its so easy..
i am adding the used circuit here.. it will be hand drawn..
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Topic: its my MODEL TRAIN CONTROL MODULE... (Read 4270 times)