Linux data acquisition with an Agilent Infiniium MSO9404A oscilloscope
I need to capture some analog data. My coworker has a National Instruments USB data acquisition module, but as far as I can tell, the drivers are all proprietary and focused on using Labview.So...
View ArticleGQL to CSV exporter for Google App Engine
The App Engine admin panel will let you run GQL queries against your datastore, but it won't let you download the results as a CSV. So I wrote a [very] quick and [very] dirty handler that does, which...
View ArticleSteam Linux audio problems
No audio at all from steam games? Try 'pavucontrol'. It'll show you when games are trying to play audio and where they're playing it to. In the "configuration" tab I had to disable built-in audio and...
View ArticleMary Meeker Internet Trends 2015
http://kpcbweb2.s3.amazonaws.com/files/90/Internet_Trends_2015.pdfSlides of interest to me:p.47: 6 of top 10 mobile apps are for messagingp.68: Social network use in 12-24 year olds: Instagram...
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Simple pump from a juice bottle
In some cars, the only way to add or check transmission fluid is to remove a hard-to-reach plug and add fluid until it starts pouring out the hole. Since the hole is in the side of the transmission,...
View Articlelibfann bugs
Looking for a general purpose neural network library, fann seemed reasonable. Jury's still out, but I see a number of shortcomings:I see people warning against using its builtin input/output scaling....
View ArticleArduino Due: toggle open drain GPIO pin
I wanted a pin on my Arduino Due to switch between pulling down toward ground and turning off (going high impedance).I tried using pinMode(x, INPUT);, but there's a bug in the arduino libraries that...
View ArticleEdimax (RTL8192CU) USB wifi adapter with Beaglebone Black
Out of the box, the stock debian distro for my Beaglebone Black didn't recognize my Edimax USB wifi adapter. But after plugging it into wired ethernet and doing an apt-get update ; apt-get...
View ArticleGetting Beaglebone black and green to work with Edimax, Keebox and D-Link...
Wifi adapters: No luck out of the box with an Edimax EW-7811UN, Keebox W150NUIEEE, or dlink DWA-121. The latter two were recognized by my Beaglebone Green, but wouldn't associate with my access point....
View ArticleBeaglebone PRU GPIO example
Executive SummaryIf you're just trying to do ordinary GPIO on your beaglebone, this is not the page you're looking for.This is about how to use certain GPIO pins on the beaglebone using the two...
View ArticleBeaglebone PRU DDR memory access
Here's some C and PRU assembly code I wrote to see how fast the PRU can write to system (DDR) memory. // Loads a .bin file into a BeagleBone PRU and then interacts with it // in shared PRU memory and...
View ArticleBeagleBone maximum PWM frequency
Using a PWM channel to get square waves (don't care about duty cycle) from my BeagleBone, looks like I can get up to 50MHz with:root@beaglebone:~# echo 10 >...
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Closeups of a LED printer head
I picked up some printer heads for an Okidata LED printer and checked them out under the microscope. This ebay auction shows what the complete head looks like. An LED printer is basically a laser...
View ArticleBeagleBone Black and Green microSD and onboard flash performance
Looks like I get about 4.3MB/sec when writing to the onboard flash on my BeagleBone Black, and about 7.1MB/sec when writing to a 64GB Sandisk Ultra 64GB microSD card.On BeagleBone Green, I get 9.4MB/s...
View ArticleBeagleBone Black/Green bus speeds
USB Host (big type A jack): 20MB/s writing to a Seagate USB3 2TB portable (spinning) hard disk (required plugging a 5V 4A power supply into the BeagleBone Black's power jack). On BeagleBone Green, I...
View ArticleGetting BeagleBone to recognize wifi adapters by upgrading the kernel
My beaglebone black wasn't recognizing my wifi adapter. apt-get update ; apt-get dist-upgrade didn't help, and I noticed that it wasn't upgrading the kernel.Looks like the way to get kernel updates is...
View ArticleBeagleBone Access Point (and working around udhcpd)
Warning: it's easy to screw this stuff up and lose the ability to ssh into the beaglebone when you reboot. Usually it was as simple as manually setting the IP address on my laptop, but you may not be...
View ArticleBeagleBone DMA notes
I've been transferring data between the BeagleBone's PRUs and main memory. If I use the PRU's SBBO instruction to store a range of PRU registers to main (DDR) memory, I find that I get around 600MB/s...
View ArticleConnect beaglebone black to android via USB OTG
With the right USB OTG cables, I was able to connect my Nexus 5X to a beaglebone black and a beaglebone green. I had to try several cables before the beaglebone would power up; I suspect it's the...
View ArticleBeaglebone black PWM minimum frequency
By trial and error, I just figured out that 1 billion is the longest period you can set for (at least this particular) PWM channel. root@beaglebone:/sys/devices/ocp.3/pwm_test_P9_31.13# echo 1000000000...
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