HO model railroad throttle
kingneb
Posts: 65
I have a small HO railroad layout in my basement that is under construction. Most voltage regulated potentiometer controlled throttles are boring, innefficient, and supply insufficient currents and voltages. They also lack the control I want. One day I decided I wanted to computer control (something to impress my friends) everything from the trains to the switch motors to the lights. I know you can do it with a DCC system (I plan on building one of my own someday), however it is too expensive. Even the least expensive "lightest one" has too many features that I do not need. Most of my locos are not DCC ready or are constructed in a way you cannot easily mod them for it (plus I am too lazy to try). My throttle uses a PWM motor control system (more efficient then pots and variable voltage regulators). It is still a work in progress and so far I am having good luck. Since the beginning of the summer I have been working on it (I attempted a voltage regulated design but it overall failed, too much heat and electrical noise problems).
How it works in a nutshell:
Two SX18 chips generate pulses for each track terminal block. They read data off the PC's parallel port and generate a 1ms clock pulse manapulated by the parallel port value (one nibble per chip, a speed setting from 0 to 10, 10 being the fastest, zero being off).
An SX28 takes data off the parallel port and uses it control switches that toggle 8 DC terminal blocks on or off, toggle an h bridge for the switch motors, and double pole single throw relays to control the direction of the trains.
power >>
Three transformers will be in this device. One large 10 amp current transformer will drive both the track outputs. A three amp will drive the terminal blocks for the DC perephrials. A small 500ma will provide power for the SX's and control cirticutry. Sounds like overkill, but I have destroyed a few pot regulator type throttles by overloading the DC periphical terminals by using the most typical layout accessoricies connected to these terminals. Manufactures of these things obviously want to cut costs so they use crappy low current components inside those things. Plus with a single transformer, throwing a switch motor causes a "brownout" across the whole layout. Mine will feature "no bugs and quirks" like this, lol.
I have a screenshot of the control panel software writen in the C# language.
Post Edited (kingneb) : 11/4/2005 3:52:14 AM GMT
How it works in a nutshell:
Two SX18 chips generate pulses for each track terminal block. They read data off the PC's parallel port and generate a 1ms clock pulse manapulated by the parallel port value (one nibble per chip, a speed setting from 0 to 10, 10 being the fastest, zero being off).
An SX28 takes data off the parallel port and uses it control switches that toggle 8 DC terminal blocks on or off, toggle an h bridge for the switch motors, and double pole single throw relays to control the direction of the trains.
power >>
Three transformers will be in this device. One large 10 amp current transformer will drive both the track outputs. A three amp will drive the terminal blocks for the DC perephrials. A small 500ma will provide power for the SX's and control cirticutry. Sounds like overkill, but I have destroyed a few pot regulator type throttles by overloading the DC periphical terminals by using the most typical layout accessoricies connected to these terminals. Manufactures of these things obviously want to cut costs so they use crappy low current components inside those things. Plus with a single transformer, throwing a switch motor causes a "brownout" across the whole layout. Mine will feature "no bugs and quirks" like this, lol.
I have a screenshot of the control panel software writen in the C# language.
Post Edited (kingneb) : 11/4/2005 3:52:14 AM GMT
bmp
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