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Re: dcc (again) tiny decoder.

Posted: Sun Nov 29, 2015 10:55 pm
by Reith01
Ozrail wrote:Maybe one day Someone will develop a Decoder chip so tiny, it can fit on a paperthin circuit board like this one.
And it can simple sit flat on the top of the motorised chassis where the electrical straps are.
That's interesting because my son recently did some work on the dash of a Mk 2 VW Golf and the circuit was printed on what appears to be polythene or something similar, guessing a little less than 0.5mm thick, wrapped around the internals of the panel. And that was from, what, the late 1980s, so it can be done. Just a matter of time.

Re: dcc (again) tiny decoder.

Posted: Tue Feb 28, 2017 5:21 pm
by PetrOs

I just joined, and i plan to order my first test T gauge train tonight, class 125 from I am going downscale from TT gauge, and plan to run the same DCC equipment as now (either Roco or selfmade Pc serial adaptor) with selfdesigned arduino boards driving servos and lights. I also ordered a pair of dcx77 decoders. I will try to post my results here - the thread was highly motivating for me, digital is a must for me - I am an IT geek :)

Re: dcc (again) tiny decoder.

Posted: Wed Aug 05, 2020 8:40 pm
by caitlin
I'm baaaaaaaaack.
I stuck a single bit of track into the sprog3, stuck that in my laptop, installed JMRI, got confused for a bit. Pressed some buttons anyway.
blit blit blit and my test rig engine and the one I managed to build with the going forwards and going backwards lights both fired up and moved under throttle.
Hopefully the frustration that drove me away is gone for a good bit and I can press on with making a DCC tguage two train layout after all.
Wish me luck?

Re: dcc (again) tiny decoder.

Posted: Thu Aug 06, 2020 12:26 am
by dkightley
Sounds good....

Don't forget to dial in some acceleration/deceleration characteristics into the decoder.

I have an oval test track about 12in x 18in and have set the speed at max throttle so the power cars runs round at a too-fast speed.....but not at a "rat out of a trap" lightning speed!! I've also dialed in a deceleration that stops a power unit in about two circuits of my test track from full whack!

This makes the units very docile and gives the appearance of a train......not a hypersonic millipede!

Re: dcc (again) tiny decoder.

Posted: Thu Aug 06, 2020 7:15 pm
by caitlin
Eurgh. Well I seem to remember that I blew my DCC engine up by accidentally doing the thing when the track voltage was on.
However it happened I seem to remember that the springs that hold the bogies on melted, so it was a sad time for everyone. I don't recall ever getting the thing to shift afterwards and just boxed it all up and sulked.

This evening I have wiped the track down with switch cleaner, penned it with that pen thing, and lightly sanded the surface also with the included fine fine fine paper.

The engine still wouldn't run so I metered out some bits of it and found the connection from wheels to spring were horrible. I wonder if some of that nasty voltage could have deposited something in the wheel pickup joint like fire or lava or magic smoke.

I spent an AGONISING headache inducing hour switching out the bogies off my proof of concept engine and replacing the springs with shiny ones (only one went PING into the ether). The Engine will now go round the whole of the starter set loop most of the time, but not all of the time and also it's going at a fair clip, which obviously reduces the chance of stalling. It stops in the same places on the circuit.

Is there any general advice anyone could share about refreshing track that has sat for years in the box? I should probably clean the connecting plates somehow.

Also sadly the wire for the red going backwards light has come off the lighting dooble so I'll have to try and solder that invisibly tiny bit back on as well before I clip it back together again in its case.

Re: dcc (again) tiny decoder.

Posted: Sat Aug 08, 2020 4:54 pm
by caitlin
Today I decided to attack the failed red light circuit. One of the pair which controls the red had come away from its pad on the light unit. Impossible to see, I need a magnifier, but i re-tinned the end of the wire held it to the pad and touched it with an iron tip that looked about the size of a house next to the part. The wire seems to have taken though and even with the violence of getting it back in the train case it's shining red in reverse and white going forwards, so I'm calling that a win.
I don't really know what I'm doing in terms of track maintenance, but I wiped the track down with switch cleaner and spent more time in the areas where the train was sticky and I'm finally back here, which is where I was 3 years ago before I blew it all up. ... LCJ2IjoxfQ

Sorry about the shakes, I was trying to find the reverse switch whilst filming.

Next up: learning how to do 'modelling' which is new to me :/ I believe I can stick my track to a board using carpet tape, so I'm going to hunting for a board and some carpet tape soon. I will so something horrible with the loop I have with some polystyrene to make a tunnel and a bridge of some kind.

Things that confuse me: This train is supposed to have an engine at the front and one at the back. I have not yet converted the other engine to DCC yet, but that's the screaming work of an evening, I hope. With DCC does one use a fake rear engine or is the some magic to feed the reverse instruction to each engine as a configured pair or should the rear engine have the motor wires reversed or something?

Re: dcc (again) tiny decoder.

Posted: Sun Aug 09, 2020 8:43 am
by dkightley
Running a second dcc loco in a consist is a doddle..

All you need to do is to wire both units identically....and then when you programme the decoders using your dcc system, there'll be a forward/reverse toggle that can be set to operate the unit in reverse. Set one to "forward" and the other for "reverse". Also, make sure you set both decoders up with the same long & short loco ids, speed and performance characteristics. Its bit 0 of CV29 that controls the direction.

Having read the tech sheet, the lights may not be reversed by this you may need to reverse the light connections in the "reverse" unit.

And a little tip, once set up, mark the underside of the power units so you know which is the "front" unit, and which is the "back"!

Re: dcc (again) tiny decoder.

Posted: Sun Aug 09, 2020 10:39 am
by caitlin
Oh, that sounds obvious now I've heard it. Thanks.
I shall figure out which of my encoders are *not* fried and wedge one in my other engine then, what fun!