Tag: raspberrypi

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A Shorter Raspberry Pi Pico

Yes, I literally cut a Raspberry Pi Pico on a bandsaw. And… it works! It still mounts and it runs code as expected.

I noticed that the back portion of the Pico seemed to have no components, and just traces running to the pins, so it was worth a $4 test.

This makes the Pico a bit closer in size to an Arduino Pro Micro or a Teensy LC.

So why would you want this? You can get a Adafruit KB2040 – RP2040 Kee Boar Driver or a SparkFun Pro Micro – RP2040 but those both use USB-C instead of Micro USB and for specific cases, that may not be ideal.

(I originally posted most of this on Mastodon, but figured I should drop it here as well.)

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Raspberry Pi as USB MIDI Host

I’ve been building USB MIDI devices for a few years now, and in the past I’ve built a MIDI controller using a Teensy that controlled an Akai MPX16, but overall I’ve not had the need to connect things up for my own needs. But now that I’ve got a few things around that have MID inputs, outputs, and throughs, I need to expand my MIDI capabilities.

It seems there are a whole bunch of devices that just do MIDI over USB and don’t have MIDI jack for “true” MIDI output. I think this is just due to it being cheaper/easier to add a USB jack to devices instead of MIDI jack. (Even though there are TRS MIDI jacks, so size/price shouldn’t be much of an issue. It may be due to demand, since most USB MIDI keyboard/devices sold are just going to be connected to a computer.

If you want to connect your USB MIDI input device to a piece of hardware that has MIDI in but is not a computer you’ll need a USB MIDI Host device. There’s the DOREMIDI USB MIDI Host Box which is about $50 and appears to be USB 1.0. There’s also the DOREMIDI High Speed USB MIDI Host Box which seems to support USB 2.0 for around $60.

As usual, I’ve got a lot of stuff laying around from past projects, so I’m recycling/pulling from existing stock here. I’ve got a Raspberry Pi 3 B (which was probably around $35 when I got it) and then you need a power supply (add $9) and a Micro SD card (add $8) so we’re up to $52 right there… and we need one more thing. I’ve had this USB MIDI Converter Cable for years, and it was about $6 when I got it. So hey, we’re under $60 but just barely.

So what do we do with this Raspberry Pi and other stuff? Well, we grab the disk image from this post titled Raspberry Pi as USB/Bluetooth MIDI host and burn it to the SD card and boot it up. Now, I was convinced I’d need to configure things but… it just worked! There’s a complete install post as well which I perused, especially when I tried to add an OLED screen. (That did not work.) To be honest I was a bit surprised it just worked out of the tin. It even worked fine with one of my 8K Controllers programmed for MIDI output.

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PrintPi 01 at Milwaukee Makerspace

printpi01-browser

It’s hard to believe I’ve been working on “Time Lapse Bot” for almost 10 years… I mean, you’d think I’d be further along by now! ;)

But seriously folks, the Time Lapse Bot project(s) got much better once the Raspberry Pi camera module came along. It allowed for a small, low-cost, portable camera device with great capabilities. I’ve been using a version to monitor my printer at home for quite a while now, and I turned my old PowerBook version into the Milwaukee Makerspace Webcam long ago, but in recent times it’s seen the most use to… monitor prints at the space.

printpi01-setup

So Mark, our 3D Printing Area Champion, asked about building some Pi camera rigs for print monitoring. So I did. I haven’t really built a proper enclosure, or made it very adjustable, but so far it works.

Basically, it captures a photo every minute, which you can see by connecting to the Pi with a web browser while on the network at the space. If you are not at the space, you can visit a web page that will show a new image every five minutes. (There’s a script that does an SCP of the file to a web server.) The other fun thing it does is compile all of yesterday’s images into a time lapse video you can download. Oh yeah, you can browser through old images and videos on the Pi when on the network, though they get deleted after X number of days to save space on the inserted thumb drive.

printpi01-back

Some scrap wood gets it just about at the right height to see the print bed. (Well, we wedged it up a bit… new version coming soon!) I’ve also got a second one in the works, along with a few enhancements I won’t reveal quite yet.

printpi01-mobile

Since there’s no screen on the Pi you need to pull up a browser on a device and check that it’s pointing where you want it pointing. I had a screen working with one of these and then one day it just decided to never work again. Annoying, so that means no screen for now.

And yes, I really do love the Raspberry Pi.

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Raspbian on Intel

eeepc-raspbian

Back in 2007 I got an Asus Eee PC, one of the fist netbooks, which were tiny laptops that (typically) ran Linux. It served me well for quite a while and I eventually turned it into the controller for my RepRap.

After I had it for a year or so my wife’s old laptop died and we were looking for a (cheap) replacement, and by that time you could get netbooks that ran Windows. Granted, it was Windows XP, but hey, it was over a decade ago. She used it for a few years until I got her a (used/cheap) MacBook Air and her old Eee PC 901 sat in my office doing nothing.

In the most recent cleaning fit I found it and was about to drop a lightweight Linux onto it (probably
Lubuntu or Xubuntu, which I’ve used in the past) but then I remembered there was a Raspbian Pixel distro for Intel machines (aka “Mac and Windows” computers) so I burned a disk, booted it up, and it was like the old days of install Linux on dodgy hardware! Manual disk partitioning, errors, multiple tries, but in the end, it worked!

So I’ve now got a laptop running Raspbian Linux. And since it’s old hardware it probably runs at a speed close to a modern-day Raspberry Pi, but has a built-in screen, keyboard, trackpad, speakers, etc. It’s like a portable Pi. (Sort of.) The one tricky thing is that when installing software you need to grab the Intel version, not the ARM version… but other than that, it’s like a Pi without the GPIO stuff. I can see it being useful for developing and testing things in a Pi-like environment with Raspbian. Maybe I’ll use it for something.

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Sleepy Noise Machine

sleepy-noise-machine

Now that summer is over and the cold months have arrived we no longer sleep with fans running, but that means we sleep without the sound of fan running, and who can sleep with all that quiet?

The wife asked if I could make something that sounded like a fan, which if you know me, is right up my alley. I grabbed a Raspberry Pi Zero and got to work. I found an audio clip of an oscillating fan (wow, there are tons of fan videos on YouTube!) and dropped it onto an SD card with Raspbian and mpg123 and had something working.

The Raspberry Pi Zero has no built-in audio output so in the past I’ve tried using a USB audio dongle, but the one I tested failed miserably in The Sonic Titan so I decided to go a different route. I used a 1080P HDMI Male VGA Audio Video Converter Adapter Cable for PC Laptop PS3 Xbox I got from eBay and then sent the audio out via HDMI so it would go to the adapter. I also needed a Mini HDMI adapter for that to plug into. It works fine, and I’ve not seen the same audio problems I did with the USB dongle.

As you can see from the photo I used a custom enclosure designed by SparkFun and modified with a stabby knife. ;)

I also used a set of powered speakers, and a dual USB power supply from Monoprice. This was hacked together rather quickly, but it all works quite well. We just plug it in before bedtime and within 30 seconds we’ve got our noise. (It also helps drown out the sound of my cat trying to wake us up at 6am.)

The thing I find most amusing about this project is that even though the Raspberry Pi Zero is a “$5 computer” it comes out to almost $30 when I add in the power supply, SD card, speakers, and HDMI audio adapter. Still, I think it’s a better option than running a full desktop computer or laptop with white noise all night. (Which apparently some people do. I’ve also heard that an old phone or tablet is a good option.)

The thing I like most about “Sleepy Noise Machine” is that is was something I could easily slap together with existing parts I had around the house. I mean, you can buy a white noise machine, but why bother when you can make your own?