Greetings! After a one year unintended and unplanned break from this great hobby, (blame hurricane Ian. I was not affected, but have been helping others recover) I am fully re-immersing myself into the wonderful world of model railroading. I have once again begun making progress on my secondary layout. Anyways, let the question begin.
For a long time now, I have wanted few things more than an animated rail-crane on my layout. So, for my first big progect back, I want to create my hearts desire... an animated crane. I have looked at other's examples online. I saw one modeler use an Athearn 200T crane. Another used a TichyTrain kit. A European modeler used a Roco crane (very similar to the Athearn 200T. I am really hoping to perform this progect on a Walthers American Crane. I want to upgrade this crane for my MOW train. It is small, but I think with the amount of surgery I will be performing on the inside of this locomotive it will all fit.
I understand the kitbashing/modifications/styrene gluing invlovled. Making a slip ring for power, mounting the motors, adjusting rigging materials, the pulleys, ect. But I simply cannot wrap my head around the DCC part of the build. Nowhere have I been able to find someone that explains in reasonable detail the decoder they used. How they wired the motors to said decoder. How they hook up 3 motors to a single decoder. Do they use a single decoder? I am a reasonably intelligent person, but DCC is not my specialty. My current understanding of a solution (pun intended) would be to use relays. Use the motor power wire as a "common" for the three motors, then have a relay triggered by a certain function button, which would complete the circuit. Then the motor is operated with the scroll wheel/buttons on my handheld. Input for any part of this progect is very much wanted, desired, and most notably, needed. Happy modeling!
JJF
Prototypically modeling the Great Northern in Minnesota with just a hint of freelancing.
Yesterday is History.
Tomorrow is a Mystery.
But today is a Gift, that is why it is called the Present.
A web search turns up the Roco 73035, which seems to do what you want, RTR. It might be worthwhile to ask them about the decoder they use. If it's a proprietary decoder, perhaps they will consider selling you one.
Hello All,
back to this great hobby!
I own a ROCO 73035 in two-rail DCC.
This unit is amazing! Well worth the price.
Unfortunately, the ROCO website lists this as "Discontinued."
But it does have a list of spare parts that are available if you want to purchase key components.
They are listed in German but you could use an online translator to figure out what each component is.
Hope this helps.
"Uhh...I didn’t know it was 'impossible' I just made it work...sorry"
The website I found, https://www.micromacromundo.com/Roco_73035_Slewing_Railway_Crane_for_Digital_Operation_DB?gclid=CjwKCAjwv-2pBhB-EiwAtsQZFD2P8XfUtoCTE4qVXRSmPdrRYALnbB6IR3i_m1-mVjHnWKdEUKkcqBoC-iwQAvD_BwE , claims to have two in stock.
I made an animated crane earlier this year (see cs.trains.com/mrr/f/88/t/294639.aspx for details). I basically did what you described. Three motors sharing one common wire, with their other wires being controlled by a DCC decoder.
I used transistors instead of relays, though, to save space. I think you'd be hard pressed to squeeze relays into a small crane. For the DCC decoder, I made one out of an Arduino Pro Mini.
I don't know about an off-the-shelf decoder, but if you know a bit about electronics and Arduinos, I can send you the code to turn an Arduino into a DCC decoder if you want to go that route
JDawgMy current understanding of a solution (pun intended) would be to use relays. Use the motor power wire as a "common" for the three motors, then have a relay triggered by a certain function button, which would complete the circuit. Then the motor is operated with the scroll wheel/buttons on my handheld.
consider using h-bridge chips rather than relays
the problem with a decoder is it only has one adjustable speed (pwm) motor function. not sure how LED outputs could be used to control a motor in either direction. maybe one output controls direction for all motors and 3 other outputs enable individual motors
greg - Philadelphia & Reading / Reading
Hey, neat progect! I have no experience with Arduinos whatsoever. I have an intermediate electrical understanding. I linked a website I found that has a electrical diagram of what I was planning on doing with a standard decoder and relays. Let me know what you think. Could I swap the relays for transistors? What's possible if I went Arduino route?
https://www.scalemodelanimation.com/Articles/Bring_a_Crane_to_Life.pdf
I think we are on the same page, but I've never used Hbridge chips before. This site has a diagram of the wiring I was considering doing with relays and a standard decoder. Would something similar work with H chips?
JDawgWould something similar work with H chips?
Geoff Bunza did what i suggested where each motor is driven by the decoder pwm (h-bridge) output and LED outputs are used to enable the motor. h-bridge chips are not a replacement for relays. however, there are solid state mosfet relays such as this from Omron
gregc JDawg Would something similar work with H chips? Geoff Bunza did what i suggested where each motor is driven by the decoder pwm (h-bridge) output and LED outputs are used to enable the motor. h-bridge chips are not a replacement for relays. however, there are solid state mosfet relays such as this from Omron
JDawg Would something similar work with H chips?
Ok, then we are in the same page. That was what I was intending to do, but my rambling on my initial post probably did not make sense. Where would I buy relays that small? I've been having a hard time finding them through Amazon or eBay.
Ok, so using those Omcron relays I can use the LED outputs to "select" one of the three motors. (Boom, Rotation, Hook/winch) Then, once a motor is selected it will be operated by the scroll wheel on my PowerCab.
I am planning on using an ESU decoder. But I have also thought about maybe a Digitrax? The Digitrax seem to be more customizable with their sound FX. Ideally I would want to custom layer the sound effects for semi-realistic crane operation. But I am not super familiar with doing that. I could always take it to a specialist for programming I suppose. Or try to buy the computer hookups. Anyways, that a ways down the track.
Do I have to change any CV's to operate a relay with the LED output? My limited knowledge tells me no, but again, carpenter by trade sooooo.
JDawgDo I have to change any CV's to operate a relay with the LED output?
the OMRON device i noted is a solid state relay, 2 back-to-back mosfet transistors that passed current in either direction.
the input and outputs are optically isolated, the input is an LED. so the LED output of the decoder should be able to drive it with a series limiting resistor
gregc JDawg Do I have to change any CV's to operate a relay with the LED output? the OMRON device i noted is a solid state relay, 2 back-to-back mosfet transistors that passed current in either direction. the input and outputs are optically isolated, the input is an LED. so the LED output of the decoder should be able to drive it with a series limiting resistor
JDawg Do I have to change any CV's to operate a relay with the LED output?
So most of that went over my head. . I typically use a 2.2k resistor for wiring LED's Would that be sufficient?
here's an image of a solid state relay circuit similar to the Omron chip which shows the back-to-back mosfets and the LED used to optically control them (like the base of a transistor).
the Omron datasheet specifies 1.5 to a max of 3ma LED current and 1 to 1.3V forward voltage. a 2.2k resistor should pass ~1.4 ma assuming a 4.5V outpu tvoltage
So ill just use a lower rated resistor to bring those numbers up to spec. Now I have to find some small motors and we are off to the races!