Re-capping a NES

I’m a low-key video game collector. Mostly because I just like games, and end up holding on to the junk I buy for each console generation. I’ll occasionally venture on to eBay to pick up the random retro title. Plus I worked at a used game store for a while back in college, which helped my collection immensely.

Sometimes, however, I don’t exactly remember where I picked up a particular piece of kit. Maybe it was scrounged from a rando on craigslist, or I found a good deal online. Who can know these things, exactly? Regardless, I have a top-loading NES, and am unsure of the origin. All I know is that recently, it’s the only working NES system that I own. I use the word “working” loosely, here. The system would power on, but would only show static. After leaving the unit running for 10 minutes or so, the video and sound would slowly start working again. Not the worst thing in the world, but kind of annoying.

I’d heard that similar problems could be caused by bad capacitors, so I figured I’d try a DIY fix. Searching around online produced one of many small hobbyist shops that specializes in retro game tech: Mortoff Games. Amid many DIY products, they sell a complete capacitor replacement kit for NES systems. I’ve got rudimentary soldering skills (and it’s only five capacitors), so I thought I’d give it a shot.

The general process is to remove the solder around the existing parts, using solder wick or a solder sucker, then replace each component. My wick was almost completely ineffective in removing the existing solder from the PDB, but I persevered. Trolling YouTube for “howto” videos produced the advice that adding a small amount of additional solder can help trigger the wicking action. I think part of the problem was that the board is so thick, too. Next time, I might try a solder sucker. Putting the replacement capacitors back in place was way easier.

Amazingly enough, after I put everything back inside the case, it worked! The unit powers on with perfect, crisp video and sound. For a beginner-level project, it was definitely a success. I’ve been introducing the kids to some older games, now that the system is working reliably. I just hope this isn’t the start of more re-capping projects…

Narrator: it was!

Comments 0 comments · Posted by Posted by Nathan at 17:05 · Tags diy nes nintendo electronics


So, after a very, very long time, I’ve decided to come back to my neglected website. A few years ago, when I was working at Nationwide Children’s Hospital, I had more than enough time to spare to learn basic system administration and write blog posts. However, since coming (back) to CoverMyMeds, I had less desire to work with computers outside of the regular 9-5. Late last year, however, I ended up switching teams, and while the new team is good, the work just isn’t as satisfying as it used to be (I could probably write a whole essay on that, but we’ll save it for another time). Therefore I’ve started itching to do “extracurricular” activities.

One of the things on my list has been to ditch ReCAPTCHA from my lame commenting system. The main reason is that, in general, I’m de-Googling. I was an early Google user (snagged my preferred username on Gmail by signing up on April 1st, 2004; remember how folks thought 1GB of storage was an April Fool’s joke?), but they’ve transformed from the scrappy tech-nerd underdog to a giant data-sucking behemoth. I’ve been taking steps to preserve my online privacy by installing browser add-ons such as uBlock Origin, which really enhances my web experience — with the unfortunate side effect that some sites break, because they expect certain JavaScript trackers to be present. This includes ReCAPTCHA. ReCAPTCHA is mostly a black box, but in general it forces users to help train Google image recognition, and in part seems to determine your “human-ness” by your activity on Google properties. I don’t really want this for myself, so it also doesn’t make sense for me to force it on the few folks who might stumble across this site.

Following a recommendation on Twitter led me to hCaptcha. It’s basically a privacy-enhancing alternative to ReCAPTCHA — it uses similar checks to prevent abuse, but is not helping Google hoover up all the datums. Of course, hCaptcha makes it pretty easy to change a few lines and start using their service. In making the change, I struggled more with updating the super old versions of the Ruby libraries running the comments app, rather than with any hCaptcha problems. I’d recommend giving it a shot!

Comments 0 comments · Posted by Posted by Nathan at 20:04 · Tags google

Developing for Apple Watch

Recently I was tasked with developing an Apple Watch extension for an existing iOS app. Since I have no interest in Apple Watch, I’d never taken the time to use one, or investigate the development process. After about a month of banging my head against the keyboard (in a metaphorical sense), I thought I would complain about my experience on the intarnets.

First of all, Xcode won’t install development builds if the watch is locked, and the watch locks itself on sleep when not being worn. So you basically have to be wear it in order to do any sort of active development. Annoying if wearing something on your wrist is irritating whilst typing.

Speaking of wearing the watch: the plastic band which is included with the cheapest watch is the absolute worst. To secure the clasp, you need to thread the loose end of the strap in such a way that the rubbery exterior rubs right against your wrist, catching and pulling out every arm hair in its path.

When testing a watch app on the actual device, the app never launches automatically. Xcode says it is running, but there’s no indication on the watch itself. My technique here is to open an unreleated app, which seems to trigger something and remind the watch that it’s supposed to be running the development target.

The watch simulator is no better. Apple Watch has two modes of interaction: touch and “Force Touch.” The simulator’s default option is to differentiate between the two by using Apple’s new pressure-sensitive trackpads (if available). Problem is, it doesn’t work. Then you need to switch input modes by using a keyboard shortcut. Except the shortcut doesn’t always work either. When trying to bring up a context menu, I’ll Cmd+Shift+2 to trigger a “deep press,” then tap the simulator, and nothing happens. It seems to randomly work on the 3rd or 4th try.

Communication between the watch and phone is slow and/or buggy. Even on the simulator! I guess maybe they’re trying to totally emulate real-world behavior, which in that case kudos all around. I will randomly get WCErrorCodeMessageReplyTimedOut errors, then do the exact same thing a second later and have it work flawlessly.

Speaking of communication, you’ll probably want/need to communicate with the parent iOS app from a number of the different views in your watch app. Problem here is that only one WatchKit class can receive messages from the phone. So you end up making your extension delegate the message-sending delegate as well, and handle communication within the watch app by sending notifications everywhere. For a simple app it might not be so bad, but that sort of architecture gets unwieldy rather quickly. Maybe I’m just a dummy, but Apple’s documentation sure doesn’t mention any other potential design patterns.

Speaking of documentation, Apple’s documentation is… not great. Many times there was no differentiation between watchOS 2 and watchOS 3 APIs. I spent a ton of time finding out that it is impossible to share UserDefaults between watch and phone. Problem is, it used to be possible, and so I fiddled about implementing “solutions” that never worked. I ran into two issues that the documentation makes no mention about. I don’t often ask questions on Stack Overflow, but did for these particular problems. The answers I got were underwhelming, to say the least.

Basically, the entire process was death-by-one-thousand-cuts frustrating. I wasn’t bullish on the entire concept of smartwatches, and if this is what the “best” has to offer, I might be put off it for good.

Comments 0 comments · Posted by Posted by Nathan at 15:11 · Tags programming apple

Image diffing using JavaScript

Recently I had need of a way to find how “similar” a collection of images were. A classic way to diff images is to take one, invert it’s colors, then draw it over the second at 50% opacity. It’s pretty easy to do this in CSS. If both images are the same, the resulting combination will be perfectly grey (rgb(128, 128, 128)).

Since we’re JavaScripting all the things these days, I figured that this technique could be implemented in JS. Fortunately, HTML’s <canvas> element has APIs that allow for easy access to raw pixel data of an image. You can call getImageData on a canvas context, which will return an object that contains an array of RGBA values for each pixel in the image. Using that data, it’s easy to invert the image a canvas displays (subtract each color value from 255), and also compare the resulting combined image.

The only real annoying bit is synchronizing loading each image, and also determining how long the entire diff process took. To that end, I created a giant array of promises, each of which was itself a promise for loading/comparing two images. The resolution of the giant promise array concludes with a timestamp comparision.

Check out the full source code. Usage is simple:

diff(sources).then(results => {;

Where sources is an array of image URLs, and results is an array of integers, indicating similarity between two images in the source array. A value close to zero indicates the two images are very similar, while a value closer to 128 shows that they are very different.

The only downside to implementing this type of algorithm in JavaScript is that it can take a very long time to compare two large images, as you are iterating over each pixel in the image, twice. For two 8 megapixel images (e.g. taken by your iPhone 5), that is 32 million pixels. As a proof of concept/toy/small image diffing tool, it works pretty nicely though.

Comments 0 comments · Posted by Posted by Nathan at 12:08 · Tags javascript diff canvas

That time when I went to an
all-girls junior high jazz band concert

I was reminiscing to a co-worker about my time in Japan, and told him a story that I’m not sure I’ve ever told anyone else. So, why not regale the internet with pointless personal anecdotes?

For those who don’t know, I taught ESL in Japan from the summer of 2004-2005. Somehow I had ended up connecting with the owner of a private school that was located in Utsunomiya. Definitely something of a backwater locale, even though it’s only 60 miles away from Tokyo. Most of my teaching was in the main office that was close to the center of the city, but I also had to regularly commute to a satellite office that was in nearby Tochigi (bizarrely, on a rail line operated by a department store). The school I worked for, being a small family-run business, had all ages of students: I sometimes “taught” preschool kids, and my oldest student was a guy in his 80s (whenever he missed a class I worried that he had died).

One of my students at this satellite office was a junior high student named Moe (pronounced moh-ay). She was actually one of my better students; since she was more fluent in English, our lessons were more high-level, and therefore less boring for me. Towards the end of the 2005 school year, my Japanese co-worker and I had finished a lesson with Moe, when she invited us both to a concert that her school band was giving. While my co-worker demurred, I thought, “Why not?” and told her I’d go (toward the end of my year-long contract, I’d determined that I was not going to stay in Japan, so attempted to have a “try anything” attitude during my remaining time).

The concert was on a Sunday, and the day before I was working in the Tochigi office as usual (yes, I had to work on Saturdays, and got Sunday/Monday off). Imagine my bemusement/concern when, at the end of the day, my co-worker suddenly pulls out a giant bouquet of flowers. “Here, you can give these to Moe.” she blathered. I worried about what people might think of a 20-something foreigner giving flowers to a young female student, but felt obligated at the same time. Cursing her under my breath, I took the bouquet, trying not to think about what I was going to do with it.

The next day, for the first time ever, I took the train to Tochigi for non-work-related purposes, and walked to the school. It felt pretty weird to be commuting on my day off. I ended up stuffing those damn flowers into my backpack, and figured I’d worry about them later. As I walked into the school auditorium’s foyer, I could almost hear people’s necks snapping as they turned to look at me. Of course, I was the only non-Japanese person there. And I don’t know why I didn’t think of it before, but of course it was an all girls school. The awkwardness of my presence had just increased exponentially. I brazened it out and found an inconspicuous seat near the back.

From what I remember, the concert itself was actually enjoyable. I didn’t go in expecting too much (remembering my own school-age band concerts), but as you might imagine, the Japanese always seem to take things to the next level. Not only was the music played impeccably, they also threw in some choreographed movement with their instruments.

After the thing ended, the students dispersed into the audience to receive congratulations from their various family members, and I had to deliver that albatross-like bouquet. Fortunately, I was able to hand it over pretty inconspicuously, thanks to the crowd.

After the meet ‘n greet, the students were called back up to the stage for a group photo. Imagine my chagrin when the photographer, seeing a white guy hanging around, yelled, “Who’s he with?” When it became known that I was Moe’s English teacher, he told me to get up on the stage for a photo, a suggestion that was enthusiastically received by the girls themselves. “Jeez, you’re tall!” I remember one remarking.

So, somewhere in Tochigi, there’s a photo of an all-girls junior high jazz band with a nerdy guy standing in the middle of the group, trying desperately not to look as awkward as he feels. Good times 😅.

Comments 0 comments · Posted by Posted by Nathan at 12:07 · Tags story gaijin awkward