This is a continuation of my last post about tinkering with the Raspberry Pi, which you can find here.
I recently purchased an accelerometer along with an "i2c" connector that makes interfacing the accelerometer with the Raspberry Pi easier. To be specific, the accelerometer I bought was a model ADXL345. You may recognize an "accelerometer" as the device that lets your smartphone know which way it’s being tilted or moved. Similarly, the Nintendo Wii famously used an accelerometer in its controller so you can swing it around to bowl or play tennis.
There were a few good tutorials online that helped me get the accelerometer working. I was surprised how easy it was to set up. Plus, on the hardware side, no soldering was needed!
I found a very simple example program online to take a single acceleration reading using python. I expanded on that example, and developed a small python module that can initialize the accelerometer, modify its calibration, and provide acceleration readings whenever requested. I could even get hundreds of readings per second, if necessary.
Out of the box, the accelerometer’s calibration wasn’t great. It provides three acceleration values (think of these as up/down, left/right, and forward/backward). When the accelerometer is at rest (i.e., sitting on my desk), two of those accelerations should be zero and the up/down direction should show earth’s gravitational acceleration (32.2 ft per second squared) in the downward direction. It was off by about 10% in one direction, but that was easy to recalibrate.
This is a really great and effective product - and you probably haven’t ever heard of it! It’s not drugs...it’s Tincture of Benzoin, and it helps keep bandages (including bandaids) stay stuck on skin.
They often come in packs of small vials. You break them sorta like a glow stick (there’s a vial within a vial) and apply it to skin in a thin layer using a built-in gauze pad. Then, let it sit for a minute or so until it’s somewhat dry and tacky. Lastly, put on the bandage.
The bandage will stay stuck much better than normal. It will endure getting wet better than normal too. This is especially useful for cuts in tricky places with a lot of movement, like hands, or where there’s rubbing, like the heel of your foot. When the time comes, the bandage can be peeled off without too much difficulty.
I couldn’t find this at CVS or Walgreens, but I eventually found it at REI. It’s probably also available online.
Last night, Jess and I saw Rufus Du Sol at the House of Blues in Boston. Rufus Du Sol (commonly just called Rufus) is a dance/electronic band from Australia.
We saw Rufus earlier this year at Electric Forest and had a great time. Last night their show didn’t quite have the same level of energy, but it was very fun. I was happy to see that the vast majority of the vocals and instrumentals were performed live at this concert - which is not often the case in electronic shows. That being said, the music wasn’t as “tight” as it should have been.
As usual, the crowd was friendly and great. Jess and I have been liking House of Blues lately, particularly because they take the security screenings very seriously. We’re looking forward to going back for another show soon.
A special ‘thanks’ to Judy, Jess’s mom, for watching Violet during our night at this show.
I like tinkering on tech projects, but I don't know much about electronics and hardware. I know enough to assemble a computer and debug simple hardware problems - but I am incapable of doing custom electronics. I want a new fun project that I could use to broaden my knowledge of electronics. While I still don't know what that project is going to be, I decided to start by playing with some LED lights because they're fun and visual.
I stocked up on various components that work with my Raspberry Pi 3. For those who are uninitiated, the Raspberry Pi 3 is a $35 computer that's about the size of a deck of cards. It's designed to be very extendable, so capable tinkerers can use it for things like robotics, smart home accessories, etc. I used the Raspberry Pi for the machine-learning traffic camera project about a year ago. For starters, my goal was to get a single matrix of LED lights working. To do this, I needed the following components:
I felt like I was in over my head when I discovered that everything wasn't pre-soldered for me. I've never soldered before, despite actually owning my own soldering iron. The first few minutes of soldering went very poorly, but I eventually got the hang of it. I made a few newbie mistakes with the soldering; for example, I soldered one of the connectors backward - so I needed to use a razor to shave a part of the plug down so it could fit into the backward connector.
After taking care of all the hardware, I booted up the Raspberry Pi and installed some software to drive the LEDs. I used an open-source software library that appears to be the go-to standard for these types of LED projects. This software should enable me to show any arbitrary image/animation on the LEDs. Plus, it comes with a few built-in examples that are good for testing the hardware; one of which is a spinning multi-colored square.
Initially, I was thrilled because the LED display sprang to life on my first attempt to run the example. But, then I realized that the screen was really only showing the color red - no blue and only a tiny bit of green. I was stuck debugging this problem for a few frustrating nights. I fiddled a bunch with the software, I tried every capable power cord in our apartment, I resoldered every connection, I even soldered a custom jumper wire between two pins (I read online that this customization improves LED performance) - but none of these things fixed the problem. I spent some time poking at the board using a multimeter when I finally realized that the wires leading to the LED matrix were carrying a lot less power than they should have been. I used the multimeter to connect the 5V input directly to the LED display, and to my amazement, the lights started glowing with the full spectrum of color. There must have been a defect with the RGB Matrix HAT (or more likely, I must have broken the HAT while soldering). To fix it, I soldered a jumper between the 5V input and the connector that leads to the LED matrix. I have a feeling a skilled electrical engineer would have found a more elegant fix to this problem - but I was pretty proud that I found any fix to the problem.
This was a super rewarding starter project for someone looking to learn a bit about electronics. I'm especially excited about this because there's a lot that can be done from here. These LED panels can be daisy-chained together to make a bigger display, plus I can program the panels to display just about anything. I already have a few ideas for the next steps - but I will keep those to myself for now.
hope i win
Ryan - start geocaching.
Here are step-by-step instructions on how to rebuild speakers if the foam rings are corroded. It is a pretty simple process that can save you the cost of expensive speaker replacements.
Jess and I got engaged! To be more specific, we got engaged while at the Hulaween music festival in northern Florida. We had a great time.
Jess and I are going to Hulaween, a music festival in northern FL. In fact, we are on the plane as I write this!
This is a Halloween-themed music festival, and Jess and I rarely shy away from wearing a costume when given the opportunity. We wanted a good costume, but we didn’t want to be uncomfortable while dressed up; plus, we wanted a durable costume that wouldn’t break while traveling. So, we decided to buy black jeans and black shirts, and paint ourselves skeleton costumes.
This was a great little project. We were able to do the painting at night over a few days. Our strategy was to mark the locations of bones on the clothes (with masking tape) while we were wearing them, and then we took some artistic approximations while painting. We’re going to supplement our painted clothes with skeleton masks and gloves we bought online.
I’m optimistic about our costumes. But, it’s hard to get a sense for how they’ll look until we really put them into action!
This morning Jess and I tried to take Violet for a walk at Cat Rock Park, a wooded park in Weston that happens to allow off-leash dogs. On weekends, there can sometimes be a line of cars waiting for a parking spot at Cat Rock, but it’s never longer than a 10 minute wait - and it’s always worth it for a nice time at the park.
When we arrived, we saw a giant new sign saying that the parking lot is now for Weston residents only. We were forced to take this new rule seriously, because we always see Weston Police doing patrols of this lot.
Shame on Weston! They are trying to keep Waltham residents out of the park to reduce the wait time for themselves. But does this mean Weston residents are not using Waltham parks, adding congestion to Waltham streets, parking in its public lots to visit its downtown, or filling open jobs in Waltham? Of coarse not. It seems like Weston wants to reap the benefits of its more-developed neighboring towns and cities, but doesn’t want to share its parks.
I get it. Making a rule is a quick way to fix a problem - but with a little bit of thought, Weston might be able to solve the parking issue, bring money into their dinky little town, and not upset their neighbors in Waltham. For example, how about putting in parking meters, then use the resulting funds to expand the parking lot?
Anyways, we ended up going to Prospect Hill Park in Waltham instead - which is open for anyone to visit, regardless of what town you live in.
Last night we saw ZHU perform at the House of Blues in Boston. This was a really fun show. ZHU is an artist that’s a little difficult to pin down genre-wise; dance, R&B, electronic, house, and hip-hop would all be suitable classifiers. I was expecting his concert to be more on the R&B side of that spectrum, but it ended up being more on the dance/electronic side. Nonetheless, the show was captivating.
While the type of music was amorphous, the concert had a consistent theme of a journey through the desert, which I think was really well executed. The theme was introduced by a few very short statements projected onto the wall, and aside from that it was very subtle. The music itself carried the theme from there. The desert aesthetic came through in the instruments and sounds more than the lyrics themselves, which was particularly impressive.
The lights at this show were at a different level than other concerts I’ve seen. It seemed like they were using projectors, but I don’t know how they got the projected images to be so sharp and realistic.
The crowd at this show was very enthusiastic. It was fun to be surrounded by so much energy. I wish every show had this many people focused on the music.
Overall, this was a great time. I’m excited to see and hear what ZHU does next.
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