This is a fantastic unit for the price, I can’t tell you how wonderful it is for doing small scale digital h/w design and firmware. I can literally time my interrupt routines, I’m sporting 5us on a dcc decoder INT routine. Sweet. I also found a really bad firmware bottleneck, I love this thing!
Here it is all hooked up to my development system. Atmel Studio 7 drives everything. This is my favorite kind of software development. Right on the metal.
Since I’m putting together a new N scale layout, or at least I’m planning it out right now, I decided I should probably give DCC a go since it’s so popular. So I ordered an inexpensive DCC starter set, the MRC prodigy Express2. I am glad I did. Just on a test loop my little DCC switcher locomotive runs WAY better than it did on DC. And since I like the feel of the MRC Prodigy Express DCC controller (more or less), I figured, why not come up with a way to use that to control, via Xbee, for my G scale stuff too?
So after much scouring and searching via Google, I came up with an input and output circuit for my control widget board.
In the above picture you can see the DCC waveforms and the really simple input side of the circuit. I’ve also got my basic C framework built out and this looks like it will be a fun project if I can ever get the time to work on it!
Anyhow, the basic idea here is read the DCC out of the Prodigy output, transmit that via Xbee and decode it on the other end. Or pass it through, or both. That way you can use any DCC handheld you want to control battery powered locomotives or even live steam ones (via intercepts of DCC commands to servos and relays, etc)
So this should be neat if I can get it to work. Something new to learn anyhow, DCC as a message stream 🙂
I have a lot less time to work on my projects than I used to so here is another sort of work in progress post.
I have the new widget boards and will be assembling several soon. I am missing a part, an SMD 140 ohm resistor for the power LED. It’s ordered.
Along with that order is all the parts I will need to intercept the DCC stream with my control widget and then either process it internally (moving servos, motor controllers, outputs, etc) or send it out to other Xbee wireless nodes. Something fun to do anyhow.
I should have a MRC Prodigy Express DCC controller soon. I will put it to use with my N scale trains but the main focus will be intercepting the DCC signals and sending them out via wireless XBee as mentioned above.
Also, if you notice, there is the Raspberry Pi 2 there beside Mr Foreman, I’ve got that up and running, very nice board. Really sweet.
Hmm. Also making progress on the CNC styrene cutting, I have large parts of the depot finished, I’ll post some pics soon.
Been sort of busy with a new job so I have not posted anything recently. I am still working on a couple of things though.
First is the completion of my G scale outdoor railroad. I’ve gotten the last major infrastructure project for that constructed but it’s going to take a while to get it skinned in concrete. I do plan to order some track soon and with luck will at least have a simple loop to run trains on.
I’m also working on my widgets again, I should have new Phase B boards in a few days. These are not a radical change, just correct one small issue on the old board, add mounting holes and a power LED. In the future I have additional plans for this board, I intend to take the remaining real estate and add a DCC interface, both in and out (if possible, using an external booster) and probably a couple of LED drivers.
My MOW critter is also coming along, I am converting it to battery power and adding widget control. I am also thinking about building a real small bobber caboose, probably with a work platform to pull behind it.
Also on the horizon is planning for an indoor N scale shelf layout. I have most of that designed, just need some tweaks.
And of course, the styrene depot shown in the last post is also taking shape.
Here I’ve added the 1/8 inch square strips and the window trim, then I shot the thing with some light brown primer.
I’ve been doing some experiments with the CNC router, trying to cut styrene. I’ve messed up and melted a sheet or two but now I think I’m getting the hang of it. I’m working on a standard N&W depot, this one is at Winfall, VA. I found the pic on the Virginia Tech Photo Archive.
Anyhow, what I have found is that styrene needs to be cut with a slow RPM and a decent inches per minute feed rate. I’m using a 1/32 inch bit at 7500 RPM and a 25 IPM feed rate. You also have to cut shallow, anything more than say .030 or so will start the dreaded melt. So I do three passes to get through 1/8 inch styrene (.125 inches). This produces a big shower of nice plastic chips or ‘saw dust’. This is what you want to see.
I wired up my yellow critter with a control widget, a Turnigy 20A ESC and a 4.8v 2300mah nimh battery pack. Works quite well. I did have to add a relay to reverse the motor but that’s already supported by the software, it’s what I use in my RS3.
A pic from the video, out on the track at Gilbert Virginia.
Just can see the Xbee in the cab. The battery is in the engine compartment along with the Turnigy ESC. The relay to toggle the motor direction is also in the cab but you can’t see it from here.
The development platform for my Dash 9 whenever I get around to it. A close shot of the control board with the Xbee. This is the same control board in the Critter. There is just enough room (I think) in the critter to put in micro servos for the couplers but I have not gotten there yet…
And here is the critter with the handheld controller.
This is my newest critter design. A freelance sort of fantasy vehicle but it came out pretty good and was fun to build. A couple of 3D peoples and some resin cast details thrown in for good measure. Everything is cut out on the CNC machine except the fuel tank which is a piece of PVC pipe. (I cut those on the band saw). Anythow, I am planning on possibly selling these as kits or at least making the plans available, not sure how that’s going to work out quite yet…