Homemade projects from RainerK

created 12.05.2009:

The pdf-files below containes schematics from my DCC-project in 2001-2003.

Driven direct from RS232 of a PC.
Contained a short circuit-detection that deactivates the DCC-output shorter then 0.1 sec. But it ignores micro-short circuits
Three seconds later the booster test disappearance of failure, if the tracks ok, the DCC-output will reactivate and give power on the tracks.
A second watch tests DCC-breakdown at the input and deactivate the DCC-output in this case.
That prevent a full-power DC on the tracks whereby a DCC-loco can run with a killing speed.
Using with rocrail-ddx should be possible and is meanwhile tested ok.

Driven from a PIA8255-card with 24 ports.
It use only one port for the 2 turnout-coils with end-switches
For decouplers it makes the current-reduce with timefunction from an elco and the resistors in a ULN2803-input.
Using with MGV50 should be possible, but it is untried.

The hardware was only build as prototypes on stripboards. It works for some years at a H0-model-railroad in the cellar from a friend but was dismantled a few years ago.

The used software there was WinLok from Hans Tanner, but a change to Rocrail is not planned because no layout actual exists.

Older topics

I've decided to construct a booster with switched DC-powersupply and HEX-FET's in the DCC-output-bridge.
I hope so to avoid - or reduce :-( - the heat sinks. We shall see . . .

updated 03.06.2009:
Internet has many offers from “universal notebook power supplys” with stepped adjustible output from 16 to 20 Volts
For an regulated unit with 3 Amps a price between 15 an 20€ to pay is cheeper then DIY
That power supply, an control-section likely to my old booster above and a H-bridge includes IRF7413 / IRF7416 (Reichelt stocked) should build for lower then 30€.
The very low RDSon from that transistors should give the stabilized voltage to output and avoid the cooling i hate

to get down to work

04.06.09: material ordered at Reichelt

08.06.09: the material is delivered,
but i found not as yet a supplier for time to work with :-(

14.06.09: a first DC-Load-Test with the delivered notebook-powersupply PWS70 was successful.
The difference of output-voltage between no-load and 3A was < 0,3V at the selected 15V to 20V nominal output.

16.06.09: a testboard for the IRF-transistors is now designed.

19.05.10: a little helper to substitute four bistable relays, applying popular IC ULN2803: rk-bistable-relay-substitute.png

03.09.10: First test of DDX at RS232 expansion board on the new PC is o.k.

16.09.10: With an old unused delta 6604 as booster my old H0 locos drives around

All unfinished projects, mentioned above, I have finally stopped. The reasons are that cheap units are available, ready assembled and delivered from far east in a short time.


Future I write in the blog: http://rainermoba.blogspot.com/

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