We have a very special event planned for the next CNC Build Club meeting on Thursday, July 18th. We are going to do a Gonzo Build with the Make With Moto crew. Make With Moto is a Velcro covered Sprinter van filled with making equipment that is touring the country. In addition to the making equipment they have a bunch of unlocked and hacked Android smartphones. They have been doing hack-a-thons around the country.
We thought it would be awesome to do something that combines our CNC hacking skills with their phone hacking skills. We would temporarily remove the “a-thon” and do a one night Gonzo build.
The plan is to do a digitally controlled camera slider. The phone would replace the camera and control the motion. We are still seeing what is feasible on the phone control options, but ideally you could control the phone from a second phone and view live video or snap shots from the slider phone.
It will probably look similar to this camera slider that was done in the past, but it will have a mount for a camera and have all the drivers on the slider.
Inventables will be supplying all the CNC materials. As the details get more firmed up, I will edit this post so check back later. If you have any other ideas, let me (Bart) know. We may be able to get materials for multiple versions.
The project was to build a “single axis” drawing machine in one night. This machine uses two independently controlled carriages on a single piece of MakerSlide rail to control a pen at the tip of two linkages. The primary purpose of the project was a fun group build and a learning exercise in setting up a non-Cartesian machine using inverse kinematics. Kinematics in this case means mathematically describing the machine to the CAM controller. The One Axis DrawBot is a very simple non Cartesian machine.
The equations used are shown above. The ends of the linkages on the carriages end are at joint and joint. The pen is at pos->tran.x and pos->tran.y. The first two equations convert the desired pen location back to actual machine locations. They were plugged into the CAM program. The last two equations do the opposite and convert machine locations to the pen location.
We had one team assemble the machine, one team wire the electronics and one team setup the controller. It took about two hours to complete that phase. We try to use newbies wherever possible, so adding solder training into the mix usually adds a little time. The next step was to setup the CAM controller.
We borrowed the CNC router computer and control box to run the machine. This has Mach3 CAM controller software on it. Mach3 has a “formulas” feature that we used to enter the kinematics. We quickly had the machine running, but it was soon clear that Mach3 was not completely up to the task. In the formulas mode, it appears to disable the DROs (digital read outs) which tell you exactly where the machine is. It was also difficult to home or tell the machine the current location. Moves in the Y axis are non linear and need to know the current location. This resulted in Y axis moves that were not 100% accurate.
The other problem was coordination. If you tell a CNC machine to move from X0, Y0 to X1, Y0, it accelerates up to the desired speed then decelerates to the end point. If you tell it to move from X0,Y0 to X1 Y10, the two axes are moving different distances, so it needs to coordinate the different axes speeds and accelerations. The X axis would move quite a bit slower to coordinate with the longer Y distance to get a straight line. Mach3 was coordinating the two machine axes, but it was not coordinating the pen axes. Moves in only X or only in Y were nice and straight, but moves in both X and Y had a bit of a curve to them, but they did accurately arrive at the end point. A graphic with a lot of short moves would not show any on the problems above so we ran a quick “PS:One” graphic. Watch the video and be sure to wait for the applause.
We will switch to using EMC2 (LinuxCNC). This has a true inverse kinematics feature that should fix the problems.
There is some discussion on the EMC user mail list to help us with this project.
Update 6/23/2013: Here is the latest (untested) version of our LinuxCNC kinematics file mykins.c
This week the CNC Build Club is going to attempt Gonzo Build #2. A gonzo build is where we try to knock out a complete CNC project in one night. Gonzo build #1 was the Quantum Delta 3D printer.
Quantum Delta 3D printer
This week we are going to build a one axis 2D drawing machine. This uses two independently controlled carriages on the same axis to get 2D motion at the ends of the linkages. The purpose is only to have a little fun and to cut our teeth on a simple inverse kinematics machine before moving onto a much more complex 6 axis machine.
If you want to help, please join us. The meeting is open to non members. Please RSVP via meetup.
This Thursday at 7:00pm Edward Ford will be hosting a ShapeOko night. Edward can help you build, complete, setup and use the ShapeOko router.
He will also give a quick overview of the web based MakerCAM program. MakerCAM can be used to create toolpaths for CNC routers. Edward and Inventables are working to develop this program into a full featured CAM program.
For those without ShapeOkos, we can talk about your CNC project or work with some of the digital fabrication equipment at PS:One like the laser cutter, CNC router or 3D printers.
This week we have a presentation by Jason Huggins (@hugs) on Bitbeam and the Tapster robot he built with it.
Thursday, May 9th @ 7:00pm, upstairs in the electronics area
Jason will give an overview of Tapster, his open source, 3D printable, mobile app testing robot. In addition to explaining why creating a mobile testing robot is not the worst idea you’ve ever heard of, Jason will give an overview of Bitbeam, the open source building toy that he developed, which Tapster’s made out of. He’ll cover his making journey as he’s experimented with laser cutters, CNC mills, and 3D printers to make Bitbeam. For fun, the talk will also include live demos of Tapster playing Angry Birds.
Jason Huggins is CTO and co-founder of Sauce Labs, a software test infrastructure company, and is the original creator of Selenium, a popular open source web testing tool. In 2011, for an art project he was working on, Jason created Bitbeam – a 3D printable LEGO-Technic-compatible construction toy. Jason lives in Oak Park, Illinois.
Following the presentation we will break away to work on various CNC projects. The ongoing group project continues to be the mid-sized CNC Router. The machine is now fully functional under Mach3 control. We can talk about the Mach3 setup and cut a few things.
We had a great presentation by Jarvis Schultz on the Microsoft Kinect last night as part of the CNC Build Club. Jarvis works with the Kinect as part of his PhD research in robotics at Northwestern University. We had an overflow crowd of close to 30 participants.
The presentation was an introduction on how to get started with hacking the Kinect. He described what is known about the internals and the data you can get out of it. He talked about the preferred open source software tools and libraries.
He gave several live demos. The pictures you see above are shots of how the Kinect saw the crowd at PS:One. The still shots don’t do justice to the coolness of watching it live. His presentation is in PDF format here.
This week we have a presentation from Jarvis Schultz on using the Microsoft Kinect motion sensor input device and other related devices. He is going to give an overview on how they work, what kind of data they can produce, what software is needed to interact with them, and what you can do with the data once you have it. He will include some live demos of what the data looks like, and what you can do with it.
Jarvis is a fourth-year PhD student in Mechanical Engineering working on robotics at Northwestern University. He is part of the Neuroscience and Robotics Laboratory, and he has been working with the Kinect since it was first available, and it has become an integral part of his PhD research. Further information is on his research webpage in case you are interested http://nxr.northwestern.edu/people/jarvis-schultz.
Thanks to Steve Finkelman for arranging this.
Following the presentation and discussion we are going to continue with the CNC Router project. We are going to add the limit switches for the X,Y and Z axes. Limit switches can protect your machine from over travel, but also provide an accurate and repeatable home position.
We are also going to setup Mach3 as the machine controller. We will try to do this while hooked up to the projector, so everyone can participate in the process and learn how to do it. Mach3 is a professional level commercial controller and is a huge step up from the typical DIY solutions, like GRBL.
After a few projects with Mach3 we will probably also install EMC2 which is an open source, Linux based alternative to Mach3.
We had a great meeting last night. We had over a dozen people working together to wire up a CNC control box. At one point we had three soldering irons going at the same time. Here is the pile of parts we started with.
Here are some people wiring the box. A really nice job was done using wire ferruls wherever we could. How many hands can fit in that little box?
Here is the nearly completed box.
Thanks to Chris, Matt, Aeva, Patrick, Donald, Steve, Jason & Alex, Cat, John, Will, Gabe, Norm, Allen and Colin. Next week we will be testing the motors, adding limit switches and configuring the software.
We will start with Mach3, then switch to EMC2 when we find a dedicated PC for that. Chris and John I think mentioned they do time at Free Geek. I am sure they could find a little PC.
The first Wednesday of the month is rapidly approaching, so that means it’s time for: Automation Night (formerly DIY CNC night)!
Join us and be part of the automated manufacturing and design revolution! Get together to discuss, fix, repair, upgrade, and show off 3D printers, routers, laser cutters, and other tools made awesome by computers.
WHEN: Wednesday October 10th 7pm (show up early if you want a tour)
WHERE: 3519 N Elston Ave, PS:One electronics lab (2nd Floor)
The second Wednesday of each month is our monthly Automation Night (AKA: DIY CNC night)!
Are you interested in automated manufacturing? Do you like the idea of owning your own 3D printer, laser cutter, automated mill, router table, or other automated tools? Then this is the night for you!
Automation Night is an ever-growing group of enthusiastic amateurs and professionals in the field of do it yourself automated manufacturing (ie 3D printers, CNC mills, laser cutters, cake frosters, etc) hardware and software.
Please come if you’re interested in learning more, already have an automated tool at home, want to show off your latest build, or just want to meet locals who are into this exciting technology!
Who: Open to the public
Where: Pumping Station: One, 3517/3519 N Elston Ave, Chicago, IL
When: Wednesday, August 8th, 7pm
Cost: Free ($5 suggested donation for non-members to help us pay the rent)
7-7:10: people show up
7:10-7:25: introductions round-robin (and sometimes a guest speaker)
7:25-’till everyone leaves: schmoozing, machine assembly and show off, discussion of tools and techniques
Image: Model of Mars Curiosity Rover by Thingiverse user ThePlanetMike