I’ve been getting some positive feedback and requests to sell wood, hardware, and electronics kits for the Mantis CNC PCB Engraver which is awesome. I got enough that I decided I am going to go ahead and do that! I have my Mantis working now and ready to start fabricating PC boards for model railroading electronics projects, several model railroading molding projects and a bunch more stuff but that got me to thinking about the build process and all of the shortcomings and gotchas I ran into – I started thinking about all the things I would improve to make the machine more functional for what I want it to do – make all sorts of model railroad pike stuff, buildings, figures, PC boards, control panels, etc… I’m not knocking the Mantis and David Carrs design in any way at all – it’s a great little machine and I am very thankful for all of David’s hard work but I feel some changes needed to be made to make the machine more functional for us model railroaders, especially if I am going be selling these to the community in kits along with documentation, plans, etc… I’d really prefer that the design be a little more personalized and the best it can be. So I am breaking the design off on a new tangent. Here’s how I got started on this path.
Notes on building and programming the Fabulous Fabio “Arduino-compatible controller” board from the Make Your Bot! website (makeyourbot.org) – This is the first in a series of Fabio Arduino-Clone related posts from Track Hacker member JT. Thank you for all of the hard work that has gone into this and for sharing it with the Track Hacker community! -craigbic (admin)
Note: weblinks have been footnoted and moved to the bottom.
Over the last six months, I’ve built, tuned, and tested a 3-axis CNC machine based on plans from Rockcliff Machine [1] Now that it is functioning and capable of milling PCBs, I decided to experiment with using it as an “Additive Manufacturing” machine, in other words, a rapid prototyping machine under computer control that uses extruded plastic filaments to build a structure based on commands generated from a processed CAD file. Continue reading »
Well, it would appear my Mantis is down and out for awhile! 
I was doing some test cutting with it – I seem to have the settings in Mach2 correctly adjusted and with a little Ports & Pins tinkering from JT, working predictably and repeatedly – last night when right in the middle of plunging the spindle into a copper PCB, everything just stopped. The 24VDC power supply to run the driver board and steppers was dead with now power LED on! 
At this point, let me take you back a couple of days prior to this event to give you a little history. Two nights ago, I was test jogging the Mantis around in Mach2 making sure everything was working fine – it was. I deactivated the steppers (hit the Reset e-stop button in Mach) but left the driver and PC powered while I was watching Hell’s Kitchen (yeah, I watch Hell’s Kitchen – sue me! lol). I started watching the evening news afterwards and fell asleep. needless to say, I woke up in the middle of the night and found that the Mantis and the PC were both off and would not come back on. I was too tired to figure out what had happened so I went to bed. The next morning, I checked around and found out that ALL of the AC outlets in my basement were out yet all the lights worked as did my TV. After getting home from work that night I did some poking around and found that the first AC outlet on that branch line out of the breaker panel is a Ground Fault Circuit Interruptor (GFCI) outlet. Thinking maybe it popped I tried resetting it. Nothing so I tired hitting the test button – nothing. It appeard like it wasn’t working. I’ve had these GFCI outlets go bad before so I suspected that was the case. I took the cover plate of f the GFCI outlet and did some testing with my multimeter and found that there was indeed 120VAC going into the GFCI but nothing out on the other end. So figuring that since this a new house (only two years old) it must be a bad GFCI outlet - I jumped out the outlet to reconnect the downstream outlets to the breaker panel. The next evening, I started doing the test cutting I mentioned above. So I unplugged and replugged the 24VDC power supply into the mains – nothing LED still out. I disconnected the Mantis from the parallel port and then replugged the power supply in and it worked! Continue reading »
Well, I promised, like two weeks ago that I would have a big update for you complete with videos now that my Mantis PCB Engraver is done – sorry the Thanksgiving holiday got in the way. I think it was worth the wait.
So here is the next big update to my Mantis build. I left off with the Y axis table done with the sides, front and back all attached to the base. The Y-axis drive nut was installed but the leadscrew and motor were not. So picking up from there I decided to drill out the 5mm holes needed to mount the leadscrews to the motors. I chucked each leadscrew in a lathe and using liberal amounts of oil, I drilled out one end of each leadscrew deep enough to insert the motor shaft fully. As it turns out, I was lucky to get these holes drilled straight and proper in the old lathe I used at work but I did so there are no problems to report. I then used the Loctite 638 to permanently mount the leadscrews to each of the steppers. I then went on to the Z-axis. This is the most complicated assembly in the Mantis since it incorporates the homebuilt spindle assembly into it. I ran into some gotcha’s on this one. As you can see from the image below, the Z-axis is composed of a plate that bolts to the X/Z connector via T-nuts, the 4 bearings, the two rods, two bottom plates and one top plate. You can also see the spindle motor mount and the pins that hold it in place.
I have started building my little Mantis CNC Router / PCB Engraver. If you’re not aware what the Mantis is, you can checkout David Carr‘s (the designer of the Mantis) blog/wiki at http://makeyourbot.org/mantis9-1 . It’s a little CNC router (footprint is 10″ x 10″) purpose built with a custom, low cost yet highly accurate and tightly built spindle specifically for engraving PC boards but it can be used for most any kind of light engraving or carving – the designer actually carved his face in chocolate in 3D relief! 
I am hoping to use the finished Mantis to carve PCBs for electronics hacks and maybe even for electronics kits available for sale here. I will continue to post my progress to the blog and let anyone interested in building this neat little machine some of the issues and gotcha’s I come across. So lets get everyone up to date here:
Well here’s another little hack that demonstrates hooking up a temperature sensor to an Arduino Duemilanove micro-controller and displaying the temperature on an LCD. Before you say anything, yes I realize it’s not directly model railroad related but I suppose it could be if you needed to monitor the temperature from something, say a model railroad volcano with lava flow. 
Really it just demonstrates how easy it is to hook up an analog sensor to the Arduino and get meaningful data out and onto an LCD. I can picture the LCD embedded in a cool layout control panel and you could certainly swap the temperature IC for something like the opto-interruptor in my hack on making a Model Railroad Scale Speedometer and be able to display the scale speed of a model locomotive right on the LCD. Well anyway, it’s a good foundation for other more model railroad related projects to come and it tests out and shows off some of the new doo-dads I picked up recently.
So I have another little hack I am working on – I have to get a locomotive and some track yet. Speaking of that, if anyone wants to be charitable and has an extra HO scale locomotive and some track (cheap toy store stuff is ok) and you want to donate it to the cause, please feel free to contact me! Anyrate, I have another hack planned and this was is very simple but neat. I want to setup an Arduino Duemilanove micro-controller to measure and report the scale speed of a passing locomotive. The way I want to do this is pretty simple – I envision (feel free to comment with suggestions, mistakes in my thinking, ideas, etc…)using two opto-interruptors (see my Arduino Controlled Model Railroad Turntable hack for a good description of opto-interruptors) as a means of starting and stopping the Arduino internal timer (might have to use an external crystal if I want something really accurate) with the opto-interruptors positioned at a known distance away from each other on a straight track, I should be able to calculate how fast the train took to traverse that known distance and then calculate the HO scale miles per hour based on that. Locomotive comes along and breaks the first opto-interruptor and starts the Arduino timer function based on the Arduino clock. The Arduino is now waiting for the train to break the second opto-interruptor to stop the timer function. Once the train does break the second opto-interruptor, the Arduino sketch then determines the HO scale speed based on the following formula:
I have finally started working on my first TRUE model railroading hack and this one is really cool! It uses Arduino, like many of the model railroading hacks I have floating around in my head or on the back of napkins, to control a model railroad turntable. For those who don’t already know, a turntable is a large turning platform with a track on it that a locomotive can drive onto and then be turned around to other tracks or even 360 degrees within the locomotives own length. Click here for a closer look at rail turntables on Wikipedia. What makes this any different than any number of model railroading turntable kits that might exist or why is it better than just sticking a motor onto the turntable with a switch? Well, because this is a micro-controlled turntable that’s why! Other turntables are not often precise and frequently misalign. The hack I am describing here uses the Arduino Duemilanove microcontroller coupled with an Adafruit Servo Motor shield to control a stepper motor and get positional feedback from opto-interrupters positioned to stop the turntable (via a deftly programmed Arduino sketch) precisely at an adjoining track location and be accurate and repeatable. I want the control panel input to the Arduino be nothing more than a rotary switch with each pole telling the Arduino to spin the turntable to a different fixed position for the turntable. Maybe an LED for each position could be used at the control panel as feedback. I want to use a stepper motor with at least a right angle gear box with good reduction so it can be easily located directly under the turntable and have enough oommph to spin large, heavy brass locomotives around. I was thinking about this relatively inexpensive (hey it’s only $16.95!) 3.3V stepper motor with built-in 180 degree gear reduction unit from MPJA, Inc. I have seen this exact motor unit built-into homemade CNC routers as a 4th axis to spin long material and use the router much like a CNC lath – good for carving ornate pool cues, spindles etc… This unit works well, is readily available all over the internet, meets my somewhat arbitrary requirements, and is dirt cheap! Can’t beat that!
Well I said I was going to run the Interfacing Flash and Arduino, from scratch tutorial from jpcote’s blog in my previous post on Using Arduino with Adobe Flash for Model Railroading. Well I had the chance to do that today and it worked brilliantly! Hooray!I have taken a few pictures of my Arduino Duemilanove board with the Adafruit protoshield installed with the LED in place along with a short video demonstrating the LED blinking with the “Blink” sample Adobe Flash program communicating with the Arduino updating it’s status from waiting to blinking. Doesn;’t sound like much and I’m sure you’re wondering what this all has to do with model railroading so I’ll tell you – this opens up a whole new realm of possible model railroad Arduino hacks such as creating a cool Flash control interface that looks like a locomotive control panel or a dispatchers panel that interfaces with sensors on the model railroad layout for realtime data along with a micro camera on the model locomotive for realtime video with the ability to control turnouts, lighting, and the trains themselves. Who knows, the sky is the limit as I am an experienced Flash programmer and feel right at home working in the Flash IDE with Actionscript. I can’t wait to start controlling trains and collecting data from a model railroad through an Arduino board using Adobe Flash.
