Truest North Compass
Workshopshed: This week, I’ve been chatting to Karl Smith, a professional story teller and maker. Karl has been telling me about the background and creation of the Truest North Compass.
Workshopshed: Thanks for agreeing to be interviewed, Karl. Can we start with why did you decide to make a Truest North compass?
Karl Smith: I first made a Truest North Compass (although I was calling it The Rumpus Compass back then) for my niece and nephew. I wrote an elaborate treasure hunt for them – they had to solve a riddle, put a jigsaw puzzle together and read the message on the back, and sort through some documents for clues. The grand finale of the treasure hunt was following the compass, by sailboat, canoe, and foot, to the base of an abandoned water tower where I had hidden a cache of glass jewels. My niece and nephew loved it. I was a professional storyteller at the time, performing under the stage name Doctor Sparks (DoctorSparks.com), and I was very interested in creating inventions that were both whimsical and practical. It wasn’t until a few years later that I realized the compass could be an incredible gift for adults.
Workshopshed: The style of the case looks very traditional, what wood did you use for it and why?
Karl Smith: The wood in the pictures is some kind of tropical hardwood that I have never been able to identify. It might be mango wood? But the final version of the compass will be maple. I was pretty dead set on walnut for the bases, but when I got the samples, the maple had this lustrous reddish tinge that pairs perfectly with the brass. It helps that maple is one of the most sustainable woods out there.
Workshopshed: I’ve built projects such as the Topsy Turvy clock where two clock hands are driven independently, what challenges did you have with the mechanics for the compass?
Karl Smith: Hoo boy, the stepper motor that drives the hands gave me no end of trouble. When I first made the version for my niece and nephew, it used a ring of LED lights instead of clock hands to indicate the direction. I constantly sampled the digital compass to get the orientation of the compass, and it was all pretty straightforward. But once I added the stepper, I found the stepper generated a complex magnetic field that made my digital compass readings garbage. So in the end I had to do some careful orchestration. Every few seconds the stepper stops completely for just long enough for the compass to take a reading, and in between those measurements, I use an onboard gyroscope to keep the position updating smoothly.
Workshopshed: There are lots of different processors and GPS modules which you could use, how did you go about selecting the right components for this project?
Karl Smith: I first developed the compass using the Arduino nano board, so once I switched to I kept using the ATMEGA328P because I already had code working on it. It’s not the newest board, but it’s inexpensive, and, even better, it’s everywhere so it’s easy to find people who have run into the same problems with it. The GPS chip was the hardest part. I really wanted to use a chip that could be assembled via SMT in the factory I’m using for my PCBs. But because of the war in Ukraine, it is nearly impossible to get GPS chips into and out of China (presumably because they can be used in deadly drones). So now I’m buying the chip I’m using off of Amazon and hand soldering it to the otherwise assembled board.
Workshopshed: How does the programming of the microcontroller work?
Karl Smith: To program the compasses I laser cut a six-pin pogo programmer jig. You can see it in action in my making-of time lapse at 0:22 in the how to assemble video. (See below) You stick the PCB in the jig, lever down the toggle clamp to make a connection to the six pins, and then run a python script that uploads the hex file to program memory and a binary file to the EEPROM. I also purpose-built the blue “Arduino as ISP” programmer you can see in the bottom left.
When we’re assembling at scale, I have a whole system planned around using thermal printed stickers and QR code readers to make the customization fool proof at each step, based on what these guys did for another personalized Kickstarter campaign: https://www.kickstarter.com/projects/centerlinelabs/kickstarter-gold-the-public-radio-the-single-stati/posts/1982192
Workshopshed: Your main PCB is outsourced, what challenges did you have getting a product made?
Karl Smith: I get my PCB made and mostly assembled through a company called JLCPCB and I can’t say enough good stuff about them. They do great work and they specialize in small orders. Nobody else can come anywhere close to them in price and speed. The biggest problems I had were design errors I made. This was my first chip with SMT components and there was a learning curve.
Workshopshed: What would you do differently if you started the process again?
Karl Smith: I’m pretty happy with the product and where I’m at with the launch. It does feel like I spent a lot of time going down false paths, but that’s just the nature of doing something new. The biggest change I will make for next time is bringing on a co-founder at the start – it was a lot to go through this all by myself.
Workshopshed: And finally, where would your compass point?
Karl Smith: My compass points to a spot on the banks of the South Ponil Creek in Philmont Scout Ranch near Cimarron, NM. I was working as a historical interpreter during the summer of 2009, pretending to be a logger from the year 1914. One night I went to bed in a canvas tent next to the creek, and when I woke up, I was a storyteller, and I hadn’t been one the night before. It’s a sacred place to me, and it’s where I’d like my ashes scattered someday.
Workshopshed: Thanks again Karl and good luck with the product launch.
If you want to know more about the compass or reserve your own, then you can find out more at http://truestnorthcompass.com/
Metal sculpture in brass, mounted on an 1800s French Coin
Love this one. I have a use for this. And maybe more in future