posts tagged with the keyword ‘raspberrypi’

2019.08.02

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.

2019.01.07

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.

2018.11.27

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?

2018.08.26

low-res-video

For the past few years I’ve been creating weird videos that (often) celebrate retro-computing with modern day low-power computing by making a Raspberry Pi connected to an old Apple display monitor play videos. You may remember Apple Watch and Apple Wait from past years of Maker Faire Milwaukee.

I’ve struggled a bit with the process of using modern software to create low-resolution videos, and I’m sure there is more than one way to do it, but I thought I’d document my process so that the next time I do it I’ll have a simple guide to follow. I’m calling this my “Guide to creating Standard Definition Video files for Raspberry Pi”.

low-res-video-01

When I create a new video file in Final Cut Express (yeah, I’m still using it) I just pretty much assume I’ll want an HD version, so that’s what I create, even if I plan to have a standard definition video as my final output. Video files get created at 1920×1080, also known as “1080″, for short. Let’s make a 1920×1080 file in Photoshop.

low-res-video-02

Our final file will be 640×480, but since SD is 4:3 versus HD which is 16:9, we need to adjust for that. If we put in 480 for the height of the file, we see it proportionally scales down the width to 853. (I remember this number from my video editing days!)

low-res-video-03

853 isn’t what we want… we want 640, so subtract 640 from 853 and what do you get? Well, it’s 213. Maths, duh! (Remember, we’re going from 16:9 to 4:3 aspect ratio, so we need to lose some of the image.)

low-res-video-04

Divide that 213 in half and we get 106.5, but since we need an integer and not a floating point, we will use two numbers, 107 and 106. Those are the number of pixels we need to crop from our video file.

low-res-video-05

I still use MPEG Streamclip because, wow, it’s awesome and it works. I’ve highlighted all the important settings I need to care about. We are loading in our full HD (1080) video file, and then scaling it down to 853×480 and also cropping it, 107 pixels on the left, and 106 pixels on the right. (Selecting “Deinterlace Video” can help too, depending on the look you want.)

low-res-video-06

If the export preview from MPEG Streamclip looks wrong, you probably did something wrong. If it looks right, then you are probably in luck! Once your MP4 file is saved, you can check it out.

low-res-video-07

I open it with QuickTime Player to check the resolution. It’s 640×480, so everything is good. So now I’ve got a Standard Def 640×480 MP4 video file that is all set to be played on a Raspberry Pi connected via composite video to an old fashioned 4:3 video display.

2017.05.14

Les Yeux

One of the pieces I displayed at Maker Faire Milwaukee in 2016 consisted of two monitors showing a pair of eyes. I was (slightly) inspired by Ben’s Video Wall of Terror.

Les Yeux

I started by filming Dr. Prodoehl to capture the movement of her eyes. The crop lines show where I planned to crop the single video into two separate videos. I also used filters on the videos to get the old TV scan line effect and add a bit of distortion. (The cropping is for a 4:3 aspect ratio display to be compatible with the old computer monitors I had on hand.)

Les Yeux

The two videos were then exported and one was trimmed to be about a half second shorter than the other one. Since the installation would be running for two full days this meant that we’d see some interesting time drifts between the two videos.

The videos were played using a pair of Raspberry Pi Zero single board computers. Like nearly every installation, there were problems involving technology, this time I think it was a bad SD card, but I quickly swapped it out and got up and running again.

Here’s a short video showing Les Yeux Times at Maker Faire in 2016, along with the two videos that were used.

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