A few years ago I built a “Terrorist Bomb” for RLBC to use as a paintball game. It was simple. It was hacked together out of a variety of parts I had lying around. It was also a huge hit.
After that, we started talking about a grander scheme. The next game would consist of three bases with buttons and lights. Initially it was traffic lights, but it eventually became the light pole we ended up using. The biggest problem with this sort of “capture the flag” type game is having referees to keep score. If we could use technology to keep score, it frees up the refs so they can focus on fair gameplay. I had been using XBee devices in my “day job,” so decided they would work great for communication between the bases and the command centre. Continue reading Base Commanders (Paintball Game)
When switching back and forth between calibres on my Lee Pro 1000 reloading press, I often have bits and pieces strewn around my reloading bench. Now, I tolerate a fair bit of disorder, but sometimes it gets to be a bit much. So… today’s quick project was to help organize my mess a bit better.
The parts I switch out when changing between 9mm and .38spl are the turret with the dies installed, the shell plate, and the case slider. (Also the case feeder, but that’s too big to store this way.)
The sous vide controller is beginning to take better shape than the prototype on the breadboard. Note, this one still has a fully configurable analogue stage. The wheatstone bridge and the op-amp gain can be changed by swapping out resistors.
The meals have also progressed beyond soft-boiled eggs.
I have been talking about this for ages… threatening to build it… even ordered parts. But, it wasn’t until a couple of weeks ago when Drew brought his Sansaire over and cooked some eggs for us that I finally got the motivation to start work on this project.
There are 101 ways you could do this. I’m going for cheap. My temperature sensor is a super-cheap PT100 PTC sensor. I am running it in a wheatstone bridge connected to a differential amplifier tuned to get the best resolution out of the temperature range I’m interested in. (49C – 74C) The output of that goes to a Nano clone, which currently only turns a Solid State Relay on and off. (I plan to use PID in the future) The relay turns a slow cooker on and off. This tiny one really isn’t hot enough, but I’m giving it a try today.
I am monitoring the whole thing over the USB/Serial port with a quickly hacked together windows application. Future plans including adjusting the setpoint and tuning the PID from this application.
So, in about an hour, I should have some perfectly cooked eggs!
It worked! These were cooked to 64.5C for one hour.
I wanted to wait until I was finished before making this post. Sadly, there has been an unexplained delay with shipping my circuit boards. So, since my job is keeping this webpage moving with new projects, here it is.
I ordered some 2.3″ 7-Segment LEDs from Aliexpress for the purpose of making a countdown timer for the SCRC Kilobots arena. The plan was to have it ready for the big Kilobots XXXI event Sept 20th and 21st, 2015.
Since time was getting tight, I went ahead and designed a circuit board and sent it away for manufacturing. (Sent the files, that is.)
I did this in the wrong order, really, since I hadn’t even tested the circuit yet. Over the Sept long weekend, I spent a bit of time and built the circuit on a breadboard to test. Fortunately, it worked.
(Yes, one of the segments is out in that picture.)
Here it is in operation. (Sped WAY up so you don’t have to watch for a full three minutes.)
Rachel is rebuilding a bot formerly known as Roadrunner:
“it’s running and it is calibrated now to weld the body and put it on almost done so excited!”
Al has done some upgrades to the drive system of Kitty Shark. He might have overdone it:
Jeremy has done a very nice job on Psychomauler. He has used the CNC router, the CNC mill, and the laser cutter during the design and build of this one:
“Psychomauler mostly put together. Had to give up on the carbon fibre after the CNC screwed up and cut it the wrong size (missed steps, or something like that), so garolite will have to do. I should still be OK for weight, I’m at about 350g currently and just need to add my titanium wedge.”
Albert held a T-Shirt Making workshop and, this time, used his vinyl cutter to cut heat-transfer material. (We have used laser-cut stencils in past workshops.) The workshop was primarily attended by SCRC members making team t-shirts for the upcoming Kilobots XXXI in September.
“Workshop went great! If anyone wants to post pics of their team shirts, please do! (We’re always looking for more website content.) Thanks to Albert for putting it on!”
One of our members, Jeremy Rans, is currently working on a hanging pen plotter, i.e. a machine that draws on a vertical surface with a suspended pen. The inspiration for the project came from this article on Hackaday. The parts being used include two NEMA-17 stepper motors for controlling the X-Y position of the pen, two EasyDriver stepper drivers, a servo for lifting the pen on and off the drawing surface, and an Arduino Uno for controlling the motors.
The main goal of the project is to make a plotter that can be easily attached to a wall-mounted whiteboard of any size. Most vertical plotters rely on the drawing surface being slightly inclined so that gravity applies the force necessary for the pen to write. Since that’s not really an option with wall-mounted whiteboards, magnets will be used to hold the pen against the board. The plotter will draw using G-Code instructions, a common choice for this type of device.
So far, most of the work done that has been done has been on the software. That includes the Arduino sketch for driving the motors, for which the AccelStepper library has been very helpful. AccelStepper allows for the stepper motors to be driven concurrently which cuts down on a lot of the math that would be involved in having to drive the motors one at a time. The other part of the software is a simple python program for reading in G-Code instructions and telling the Arduino how many steps each motor will need to take to satisfy each instruction. The software was recently tested with a quickly hacked together plotter which can be seen in action in the video below.
With most of the programming work out of the way, the current focus is on the design of the pen holder, the motor mounts & the line guides. The line guides are basically magnetic hooks that the suspension line will run through at the upper left and right corners of the desired drawing area. This allows for the motors & other electronics to remain close together.
Stay tuned for a future update in which we’ll feature the finished product!
For those of you who have built a robot kit with me at Saskatoon Techworks, I will be holding the first programming workshop on December 13th, 12-3PM. If you are available and plan to attend, please email me at firstname.lastname@example.org. Please bring your robot, and if possible, a laptop.