John Park, Full-Time Maker for Adafruit


John Park workshop

I’m thrilled to announce that after a decade of moonlighting in the maker movement, I’m now officially a full-time maker and content creator! Starting this week, I’ll be working from my Southern California workshop, designing and building projects and videos for Adafruit Industries.

Adafruit is an open source hardware and electronics company founded by the awe-inspiring engineer Limor “Lady Ada” Fried, and co-run by the highest energy element on the the periodic table, Phil Torrone. I’ve know these wonderful people since the beginning of the maker movement, working together on Make: magazine, Maker Faires, and the Emmy-nominated Make: Television show on American Public Television. I’m proud to be joining them and the rest of the incredible team in our shared goal to encourage and enable anybody to build anything.

There are so many projects I’m excited to start building and sharing in videos and online tutorials. I’ll be making things to appeal to people with wide ranging passions, including cosplayers, home brewers, gamers, magicians, rock climbers, hot rodders, modernist chefs, lock pickers, kids, musicians, mixologists, Burners, escape room designers, aerialists, cyclists, teachers, animators, and coffee fiends, to name a few.

If you’ve got an idea for something you’d like to see me make, please drop me a note in the comments or on my Twitter @johnedgarpark.

You’ll be able to watch my Adafruit videos here, my Learning System tutorials here, my posts on the Adafruit blog. I look forward to meeting you in the Adafruit online hangouts. I’ll also be doing collaborations, speaking, teaching, and other maker activities, please follow my blog for updates — you can subscribe in the sidebar over there on the right.

Build a Behemoth Cold Brew Drip Tower


[This is republished from an article I wrote for Make: magazine]

I love cold brew coffee. Its rich and delicious flavor, and low acidity, means it tastes great over ice. Traditional hot-brewed coffee methods simply can’t compare; when chilled and served on ice they tend to taste diluted and acidic. I have a small commercial drip tower that works very well, however, given the fact that cold brew takes up to 18 hours to brew, it’s disappointing to finish it off in just a few drinks. You can buy large cold-brew towers, but they’re very expensive, aimed at coffee shops. I decided to build a much larger brewing tower from scratch, and to make it considerably higher precision while I was at it — drip rate is everything when it comes to cold brew — using a microcontroller-driven solenoid valve for exact drip rate.

A cold-brew coffee tower consists of three main parts: a water receptacle at the top with a drip control valve, a chamber for grounds in the middle where the brewing takes place, and a carafe to receive the brewed coffee at the bottom.


Sourcing parts was a bit of an adventure. I had planned to use chemistry lab glass for all three systems, but eventually realized that this would be either too expensive, in the case of using a separatory funnel for the tapped water receptacle, or impractical — a Buchner funnel large enough to hold 150 grams of ground coffee would be much too squat and wide to saturate evenly. After much hunting I found the ideal components: a water serving pitcher for the top receptacle, a siphon brewing upper beaker as the grounds chamber, and a flat-bottomed boiling flask as the receiving vessel. For a bit of spiraling glass laboratory aesthetic I added a Graham condenser to the mix, purely for looks.

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Protractor Head Square Cleanup


I just picked up an excellent vintage Brown & Sharpe No. 4 combination square protractor head and blade for $20. It was in good shape, just needed some cleaning and surface rust removal. Made in Rhode Island, it’s a high-quality, forged and hardened precision measurement tool. Not sure of the vintage.

These are great for transferring angles, measuring and marking at non-square (or square) angles along the length of the blade, and using the bubble level not just to check square, but determine the exact angle of out-of-square surfaces. The blade can flip to both edges on both sides, giving four different graduation sets.

Here’s a photo essay of my cleanup process.

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Toner Transfer PCB Silkscreen Fail

This didn’t work.

I wanted to add the graphical silkscreen layer to the top of my guitar fuzz circuit board. I printed a mirror image on the laser printer, aligned it, ironed it, saw the terrible result, and made a sad face.

Here’s plan B, stick a positive version on with double stick tape. Super pro.

Making a guitar fuzz pedal circuitboard


NOTE: I accidentally reversed the electrolytic capacitor (C2) in this drawing.

I’m making a guitar effect pedal for my son, who’s been learning to play guitar and recently borrowed a beautiful Danelectro from my friend Adam Iscove. I found a simple fuzz circuit online called a Bazz Fuss  and decided to replicate it.

I started off on a breadboard and got a good sound out of it, so now I’m making a circuitboard for it.

I re-created the circuit schematic in Eagle CAD, as seen here. I’m not an electrical engineer, and I’m certain I’ve done many things incorrectly and look forward to hearing suggestions on improving things. Heck, I haven’t even soldered it together and tested it yet, so I probably won’t work until iteration #7…


Next, I manually placed and routed the components, also in Eagle.


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