We are working on the electronics for a hands-on museum exhibit that tests reaction time and shows how you can improve their reaction time through practice. The main components of the control unit are a BeagleBone Black, an 8-Channel Relay Board (to control a set of race track staging lights), and a custom-made protoboard with resistors and screw terminals (that take input from the start buttons and gas pedals). The exhibit consists of three race cars. Each car has a start button and a gas pedal. When someone presses a start button, then a set of large staging lights count down Ready, 3, 2, 1, Go! The staging lights are similar to what you would see at a drag racing track. The system then measures the time it takes each driver to press his/her gas pedal. The results are displayed on a large monitor (connected to the BBB’s HDMI port) that everyone can see. If anyone presses his/her pedal too early, then the “Too Early!” light goes on and the screen indicates that it was a false start. The system also includes appropriately-timed drag racing sound effects output through the BBB’s HDMI port to an amplifier and set of speakers. Here is a picture of the control board we made. It will go inside a clear acrylic box to protect it. This is a Rev C BeagleBone Black running Debian Linux. The custom software is written in Python.
The Centurion is an automatic-targeting paintball sentry gun. Its purpose is to guard a doorway, alleyway, or any open space. It watches an area with its camera. If it sees movement, it aims its guns at it and shoots at a high rate of fire until the target leaves the field of view or stops moving. As long as the target keeps moving, the guns track the movement and keep shooting. It can also differentiate color. So, for example, team members with blue sweat shirts could be allowed to pass, but enemies with red sweatshirts will be dealt with severely. The main components are:
Motherboard with a Corei5-4570S Quad Core 2.9Ghz, 8GB RAM, 120GB SSD, & WiFi module
Wide-angle HD webcam
8-Channel Relay Board
12v 7,000mAh Lithium-Ion battery
Actobotics Pan-Tilt Turret
Actobotics tubes, channel, brackets, clamps, shafts, ball bearings, gears, and other components
Actobotics Hitec Servos
Maxbotix ultrasonic range finder
(2) high-performance paintball guns (Dye Proto Reflex 14’s with custom modified barrels)
(2) targeting lasers
(2) electric ammunition hoppers (not shown)
(2) air tanks (not shown)
Portable keyboard, mouse, and keyboard (not shown)(not necessary for operation)
We started out with the code from the open source Project Sentry Gun, which is written in Processing, and then went from there.
The Centurion is one of several projects that we work on just for fun when we aren’t working other projects. The whole system isn’t done yet, but we’ve made good progress on it. We are currently working on two new projects for the New York Hall of Science, so we won’t be getting back to this one for a while, but we thought we would share our work-in-progress.
We hacked into the circuit board of the paintball guns in order to load and fire the guns electronically.
We reverse engineered the gun’s circuit board to figure out where we needed to hack into it in order to control the firing sequence.
We built an aluminum enclosure for the electronics and the base of the pan-tilt turret, which is made with Actobotics hardware and servos:
Genevieve wiring up the relay board, which will control the firing of the paintball guns. Is that a gentle smile or a devilish grin? Is she thinking about paint balls flying at anyone in particular?
Genevieve soldering the power distribution board.
Genevieve wiring up the control switches and buttons on the back of the electronics enclosure.
Back view of the Centurion Sentry Gun, including multiple jacks and push buttons:
Front View, including the front port that the camera looks out of. When we are done, the port will be covered in glass.
At Beatty Robotics, we’ve made good use of our gantry-style CNC mill over the last few years. We’ve built all our robots to date with it. Recently we decided to augment our machining capability with a vertical CNC mill. Our current mill has been excellent for machining large flat parts out of sheet aluminum, but now we wanted to be able to machine parts that were deeper and more three dimensional, as well as use coolant and a greater variety of tools. After extensive research of all the various machines available, we decided on a Tormach 1100. We bought and installed the base Tormach machine, then extended it with various add-on kits and our own customizations to turn it into a lean, mean milling machine. We’ve only had the mill for about a month, but we love it so far. The Tormach’s capabilities, features, and price are geared toward professional machinists, small businesses, and prototype shops, so the Tormach isn’t affordable for most hobbyists, but it is an excellent machine. In future posts, we’ll show you some of the parts we’ve made, but for now, here are some details on our installation.
The base machine weighs 1130 pounds, so in addition to the mill itself, we purchased Tormach’s stand kit to make sure we supported the machine properly. The chip tray’s bright white color didn’t fit too well in our shop, so we painted it oil rubbed bronze (in case you were wondering why it doesn’t look like other Tormachs you’ve seen). We then constructed a full enclosure of our own design using 80/20 and 1/4” polycarbonate plates. The enclosure keeps the flood coolant and chips contained, reduces shop noise, and improves safety. Part way through the building of the enclosure we ran out of the metal plates and brackets we needed. It was late on a Friday night and it stopped our project dead in its tracks. No problem. We jumped on the CAD system, designed the parts, and machined them on the mill. Very cool.
The control panel on a standard Tormach is located on the electrical box just to the right of the spindle, which put it inside the enclosure, so we rewired the electrical controls so that they were accessible from outside the enclosure. We also simplified the controls to just what we needed: Emergency Stop, Start, Computer Power Button, and Spindle Load Gauge. Everything else is controlled via the computer screen.
When we setup a part in the machine, we use an electronic touch probe, which allows us to find the X, Y, and Z position of the workpiece very precisely, which is critical to making good parts. We love using the probe, but the problem was that there is a bug in the Mach3 software’s probe wizard. In some cases, when you run the probe wizard, Mach3 turns on and spins the spindle, which yanks out the probe cable, whips it around at high speed, and destroys the probe. To make sure this never happened to us again, we wired the spindle power through a custom bracket we designed with a high-amp lever switch. When the probe is resting in the bracket, which is now its normal storage location, then the spindle will operate as usual. But when we pull the probe out and put it in the spindle for probing, the lever switch will cut power to the spindle so it can’t spin even if the buggy software tells it to. It was a really nice way to fool-proof and simplify the job setup procedure. [Important April 2015 UPDATE: Tormach now offers their new own, internally-developed Path Pilot software instead of Mach3. Path Pilot is a much better, more robust approach for running the Tormach. And best of all, this was a free upgrade to all previous Tormach owners!].
In the picture below, you can see the probe resting in the custom switch bracket we designed in SolidWorks and then machined on the Tormach.
Clamping and fixturing is often the most time consuming and troublesome part of running a job, so we put significant time into figuring out the best approach for our particular situation. After studying all the different kinds of parts we plan to machine, we designed our fixturing system around a 6” Kurt Vise with quick-change SnapJaws. Our goal was to leave the vise in the machine for 95% of our jobs. One of the trickiest elements of building the enclosure was to make sure that the vise didn’t hit the enclosure wall during the machining operation. It’s hard to tell from the picture, but the large door on the front of the enclosure is actually extended out 5” from the rest of the enclosure in order to give the vise plenty of room when the table is moving. Here’s a picture of the Kurt vise mounted into place, where it was promptly buried beneath a mound of chips.
The mill with the enclosure door open.
We also designed and machined a bracket shelf so that we could place the jog controller exactly where we wanted it, hovering on the right side just below the door so that we could use it whether the door was open or not.
One of the best things about the Tormach is the Tormach Tooling System (TTS). It’s a well thought out approach to standardizing and simplifying tool heights so that mid-job tool changes are super fast and accurate. Here’s a picture of the tools and tool holders we have so far. The beauty of this system, especially when combined with the quick-change capability of Tormach’s compressed-air-powered drawbar option, is that you can change tools in a few seconds and be certain that the new tool is in the exact position it needs to be. This means that you can use the right tool for each portion of the job without worrying about changeover issues. Our tools include various sizes of end mills, chamfers, radius tools, modular insert mills, a fly cutter, engravers, drills, and taps. It has really expanded our capability.
We are looking forward to making many interesting parts with our new machine. I would like to thank the folks at Tormach for designing and building such an excellent mill, and for their email-based assistance when we had questions. I would also like to thank our friend and colleague Mike Dutra here in Asheville for his help during the installation process. His confidence with a 2-ton engine hoist moving around a 1130 pound hunk of iron was very helpful. He also helped out in many other areas of the installation process. Also, a special shout out to John over at CNC NYC. If you’re into machining, be sure to subscribe to his YouTube channel. Finally, I would like to give a nod to Camille and Genevieve who couldn’t wait to start using the machine. They started using it even before we had finished the enclosure (chips were a-flyin’ fast and far) and they have already proven themselves to be excellent machine operators. They’ve both made some great parts already and it’s just the beginning. We’ll keep you posted.
At Beatty Robotics, we love building custom computers. Our latest computer project is a “Mini CAD System” for doing Computer Aided Design. Our goal was to build a small, but very powerful computer for running Solidworks and our CAM software HSMWorks. The computer required a super-fast CPU, a discrete Solidworks-approved graphics processor, plenty of RAM, a SSD hard drive, and the ability to run Windows 7 or 8 (Solidworks requires Windows). We also wanted to be able to customize the computer and overclock the processor to maximize its speed. After doing the necessary research to make sure everything was going to fit our requirements and work together without compatibility problems, we selected these components:
Intel i7-4790K CPU (4.0 Ghz / boost to 4.4 Ghz)
Asus Z971-PLUS Mini-ITX motherboard
16GB RAM (Crucial Ballistix)
512GB Transcend M.2 Solid State Drive (SSD)
It’s hard to tell from this picture, but this “hard drive” is TINY, just .86″ x 2.36″ x .088″. It fits into a slot on the underside of the motherboard. Incredible.
We have the computer assembled, configured and running. Here’s what it looks like so far. We’ve mounted everything on a sandwich of metal plates that we machined. In order to reduce the overall height of the computer, we mounted the graphics card horizontally beneath the motherboard and used a long PCIe “riser” cable. We’ve never seen this done before, but we’re hoping it will work. Everything seems to run fine, including SolidWorks.
So far, so good. It’s 6.7″ square, which is very small for a fast, powerful CAD system. The next step is to build a case for it. There are many excellent commercial cases available for Mini ITX motherboards, but most of them have lots of extra space for a large power supply, conventional hard drives, and an optical drive, all of which we’ve eliminated from our design. The cases that are very small don’t have space for the graphics card. So, we decided it would be fun to design and machine our own small case using our CNC. We haven’t started that part yet, but we’ll keep you posted on how it goes.
We became interested in morse code and began learning how to use it by tapping rocks and writing dot-dash-dot messages, so we decided to build a proper telegraph system. But we didn’t want just any telegraph, we wanted something cool that looked good and that we could use at a distance. We scoured eBay and found two authentic telegraph keys and sounders from the 1800’s. We cleaned them up, rewired them, got them working, mounted them, and then integrated them into an Arduino microcontroller and xBee RF radio so that they would function wirelessly. Our friend Danny made us some awesome wooden boxes out of the wood from an old barn on our property. We mounted the electronics on copper and brass plates that we machined on our CNC. Then we soldered it all up, programmed the Arduino, and ran our initial tests. The results were excellent. We can now communicate via telegraph even when my sister and I are in our separate rooms, which are on opposite sides of the house, and when we are outside. Here are two postings from our Workshop blog as we were building the telegraphs. I’ve put some pictures of the nearly completed telegraphs below. We aren’t quite done yet. There’s still a few more things to do, but they are looking and working great so far.