Archive for the ‘Projects’Category

Base Commanders (Paintball Game)

Paintball Game for Ranger Lake Bible Camp

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.

aka "Game Timer"

aka “Game Timer”

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.

The system I ended up building consists of a Parallax Propeller based circuit board in a Seahorse case with an SLA battery for power. The light pole uses LED strips intended for ground effect lighting and the buttons are standard arcade machine buttons. Communications are provided by XBee S3B-DM modules, which are probably way overkill for the application, but I decided to start at the top rather than have to work my way up until I found what worked. The base station communications is provided by a stock Digi XBee development board connected to the computer by a USB cable.

Base Commander Bases

Base Commander Bases

Base Commander Light Pole

Base Commander Light Pole

After the initial software developer fell through, I took it upon myself to write the command centre software as well. (I don’t claim to be a software guy — especially GUI applications.) The software monitors the bases throughout the timed game and counts up the score for each team while the base is held by them. It will also remotely reset the base states when starting a new game, and puts all the bases into “win mode” at the end of a game. (They slow blink the winning team colour and no longer respond to button presses until the next game is started.)

The software was written in Free Pascal using the Lazarus IDE. Lazarus is a cross platform development environment and the plan, initially, was to install the software on an older Macintosh laptop. Sadly, I couldn’t get the serial communications library working on the Mac, so I ended up installing the software on an old Windows XP laptop.

Command Centre Software

Command Centre Software

July 4th was the first full day of camp for the 2016 season, and a perfect day to try out the new game.

We installed the base stations at locations around the paintball range and set up the command centre in the safe area building. I was a little worried about the fact we had a metal wall between one of the bases and the command centre, but communications was not a problem.

Speed Bump

Speed Bump

Black Snake

Black Snake

Command Centre

Command Centre

I watched the first couple of games from inside the safe zone. One of the staff provided the players with game progress updates over the PA system. Finally, on the third game, I decided to venture out and watch the action first hand. Sadly, after one picture, my phone announced to me that my memory card was full… and I didn’t feel in a particularly safe situation to go through my pictures and delete old ones. So this is the only photo I got while paintballs were whizzing around me. Yes the ref is protecting his junk. He was caught in the crossfire between a couple players. Yes, he did get hit.

In The Action

In The Action

It seems like the game was a huge hit. Many of the campers thanked me for building it, and a few also put two and two together and asked, excitedly, if I was also the guy who built the “Terrorist Bomb.” Yes. Yes, I am. (But in polite company I refer to it as the “Game Timer.”)


07 2016

A Quick Sunday Afternoon CNC Project

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.)


A few measurements and some quick drawing in Aspire and I’m ready for the router.


I always enjoy watching Goliath work.




and back home!



05 2016

Sous Vide Update

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.




01 2016

Temperature Control (Sous Vide)

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.
IMG_20160106_185521 IMG_20160106_185614


01 2016

Countdown Timer Update

Although the boards didn’t arrive in time for the September event, they are now here. I populated and tested one. I think these will look great for our January event.





09 2015

Countdown Timer for SCRC Kilobots

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.

So far…

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.

2.3" LEDs


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.

Breadboarded Clock


(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.)


09 2015


Some of our members have been hard at work building combat robots for the upcoming Kilobots XXXI which will take place at the Saskatoon Comic & Entertainment Expo on September 19th and 20th, 2015.

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.”


08 2015

T-Shirt Workshop

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.

Kurtis writes:
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!


08 2015

Project Report: Hanging Pen Plotter

hanging plotter

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!


01 2015

Workshop announcement: Robot Kit Arduino Programming 1

Hi everybody,

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 Please bring your robot, and if possible, a laptop.

For more information, check the event page.


12 2014