Go to advanced search

by ab1jx
Thu Apr 04, 2019 10:13 pm
Forum: C/C++
Topic: Making sense of ADS-B checksums & bitfields
Replies: 52
Views: 5854

Re: Making sense of ADS-B checksums & bitfields

I haven't dealt with NTP in a long time, except installing the Debian package seems to set it up nicely. OpenBSD has their own simplified adaptation of it. When I started trying to use it it was pulling a time/date over shortwave radio from WWV or CHU (audio connection to a sound card) decoding the ...
by ab1jx
Thu Apr 04, 2019 3:56 pm
Forum: C/C++
Topic: Making sense of ADS-B checksums & bitfields
Replies: 52
Views: 5854

Re: Making sense of ADS-B checksums & bitfields

Hmm, probably like these folks do with lightning strikes http://en.blitzortung.org/live_lightning_maps.php I think they expect microsecond accuracy or so. That's all done by triangulation and it's just an impulse so timing is everything. No numbers like on planes or positions in the reports. But the...
by ab1jx
Thu Apr 04, 2019 9:53 am
Forum: C/C++
Topic: Making sense of ADS-B checksums & bitfields
Replies: 52
Views: 5854

Re: Making sense of ADS-B checksums & bitfields

Cut your antenna down to 68mm (roughly quarter wavelength for 1090MHz) and you'll double the number of aircraft you'll receive. Nah, I've got one of these around, I just didn't go look for it. https://www.sprut.de/electronic/pic/projekte/adsb/adsb2.gif From Sprut's page, made for 1090 MHz. It has 3...
by ab1jx
Wed Apr 03, 2019 11:06 pm
Forum: C/C++
Topic: Making sense of ADS-B checksums & bitfields
Replies: 52
Views: 5854

Re: Making sense of ADS-B checksums & bitfields

Yup, it works pretty much like Sprut's, not crazy about the CPU usage though. piaware_ss002_800.jpg (Resized small enough to post here) Not as much fun as writing my own, but contributing data to FlightAware's database is probably a good thing. Takes 30 - 50% CPU (with Firefox) on a Pi 3B, sort of n...
by ab1jx
Wed Apr 03, 2019 12:24 am
Forum: C/C++
Topic: Making sense of ADS-B checksums & bitfields
Replies: 52
Views: 5854

Re: Making sense of ADS-B checksums & bitfields

OK, thanks, hadn't heard of it. Sprut does mention Flight Aware though. A network of machines sending reports to a central location to be redistributed makes a lot of sense. A little like Blitzortung does with lightning strike data. Too much load for a Zero though by their forums. Solar powered Pi r...
by ab1jx
Tue Apr 02, 2019 9:49 pm
Forum: C/C++
Topic: Making sense of ADS-B checksums & bitfields
Replies: 52
Views: 5854

Making sense of ADS-B checksums & bitfields

On a whim I wanted to check the RTL2832 dongle I'm using for a different project by running rtl_adsb. modes_gui seems buried in a long backlog of QT & Python updates so I thought it would be fun to write something (in C) that takes the output of rtl_adsb and plots it on maybe an Open Street Maps map...
by ab1jx
Tue Apr 02, 2019 8:43 pm
Forum: C/C++
Topic: CT Clamp with Raspberry Pi (AC Current Sensor)
Replies: 5
Views: 4960

Re: CT Clamp with Raspberry Pi (AC Current Sensor)

You could always double check by measuring the current to a 100 watt incandescent bulb, or a few of them. I'm not sure how close to 100.0000 watts they come but as dummy loads you can switch in and out a few incandescent light bulbs aren't bad. 2 should read about twice the current as 1, etc. Gives ...
by ab1jx
Wed Mar 27, 2019 1:27 am
Forum: General discussion
Topic: High Endurance SD card
Replies: 47
Views: 18822

Re: High Endurance SD card

I just pre-ordered a 128 GB Sandisk High Endurance at $29.22 https://www.bhphotovideo.com/bnh/controller/home?O=invoice&A=details&Q=&sku=1466563&is=REG Sandisk only has up to 64 GB in high endurance so far. But you can also pre-order a 256 GB for $69.95, click on the box at the bottom. I've been buy...
by ab1jx
Sun Mar 24, 2019 4:39 pm
Forum: Graphics programming
Topic: OpenCL on the VideoCore IV!
Replies: 82
Views: 58619

Re: OpenCL on the VideoCore IV!

Anybody get it to mine yet? I don't want it just for that but I'm not up to writing OpenCL code yet. I'm trying to use a cgminer from https://github.com/ozbenh/cgminer I've been mining Litecoin and Bitcoin as a hobby for a couple years, I've built and used several versions of cgminer, never tried wi...
by ab1jx
Sun Mar 24, 2019 12:45 am
Forum: Graphics programming
Topic: OpenCL on the VideoCore IV!
Replies: 82
Views: 58619

Re: OpenCL on the VideoCore IV!

Alright, maybe I got it fixed. From my notes: zero3# apt-get --fix-broken install Reading package lists... Done Building dependency tree Reading state information... Done 0 upgraded, 0 newly installed, 0 to remove and 0 not upgraded. 2 not fully installed or removed. After this operation, 0 B of add...
by ab1jx
Fri Mar 22, 2019 9:32 pm
Forum: Graphics programming
Topic: OpenCL on the VideoCore IV!
Replies: 82
Views: 58619

Re: OpenCL on the VideoCore IV!

I installed on a ZeroW using the debs mentioned in this thread. I think it's mostly OK, I get this clinfo output: This is from my ZeroW 3/22/2019 Number of platforms 1 Platform Name OpenCL for the Raspberry Pi VideoCore IV GPU Platform Vendor doe300 Platform Version OpenCL 1.2 VC4CL 0.4 Platform Pro...
by ab1jx
Wed Mar 20, 2019 3:36 am
Forum: Advanced users
Topic: Huawei E3372 and E3531 working on PI Zero
Replies: 6
Views: 11495

Re: Huawei E3372 and E3531 working on PI Zero

I gave up and bought a NOS Motorola phone instead. I couldn't make the Huawei see the local phone towers I normally use (AT&T) despite a couple plug-in gain antennas near the ceiling. It sees a tower from a different company (T Mobile) but that does me no good.
by ab1jx
Wed Mar 20, 2019 3:28 am
Forum: Interfacing (DSI, CSI, I2C, etc.)
Topic: Need help with ABElectronics ADC board
Replies: 0
Views: 114

Need help with ABElectronics ADC board

Off on a tangent, sort of, take a look at the ads1115 Pi add-on boards. Under $5 and 4 channel 16 bit or 2 channel with differential input. A bunch of different full-scale voltage settings because there's also a gain block. I think you can get down to about 0.2 volts full scale input with a resoluti...
by ab1jx
Mon Mar 18, 2019 10:45 pm
Forum: Graphics programming
Topic: SPi Display Questions?
Replies: 22
Views: 3352

Re: SPi Display Questions?

They said the touchscreen is SPI i.e. that thin-film resistive layer stuck to the front of the display that registers where you touched it. The display itself is DPI which the VC4 can output to without bothering the CPU. OK, DPI https://en.wikipedia.org/wiki/Display_pixel_interface which is part of...
by ab1jx
Mon Mar 18, 2019 6:28 pm
Forum: Graphics programming
Topic: SPi Display Questions?
Replies: 22
Views: 3352

Re: SPi Display Questions?

I asked at http://www.raspberrypiwiki.com/index.php/2.8_inch_Touch_Screen_for_Pi_zero This is SPI? Or HDMI? 16 bit color or 24 or 32? and the answer I got was Hello, The 2.8inch screen is consist of display screen and touch screen, The display screen is DPI, and the touch screen is SPI. And the scre...
by ab1jx
Mon Mar 18, 2019 6:12 pm
Forum: General programming discussion
Topic: Mixing C and assembly?
Replies: 18
Views: 2233

Re: Mixing C and assembly?

This link has a working Debian Buster 64 bit: https://wiki.debian.org/RaspberryPi3 Last updated Feb 7, 2019. Thanks, I grabbed a copy, maybe I'll go back to using it. I'll bet it's the same thing later in life. 64 bit is slightly slower though and being RAM-challenged at a fixed 1 GB there's no gre...
by ab1jx
Mon Mar 18, 2019 2:11 pm
Forum: General programming discussion
Topic: Mixing C and assembly?
Replies: 18
Views: 2233

Re: Mixing C and assembly?

https://people.debian.org/~stapelberg/raspberrypi3/2018-01-08/2018-01-08-raspberry-pi-3-buster-PREVIEW.img.xz Seems to still be there, it's over 1 year old so it needs a lot of updates. But it's Buster, not Stretch. From being at a Debian URL I thought it might be sort of official, but I'm on the De...
by ab1jx
Mon Mar 18, 2019 1:44 pm
Forum: General programming discussion
Topic: Mixing C and assembly?
Replies: 18
Views: 2233

Re: Mixing C and assembly?

I was running 64 bit Debian on a Pi a year ago, went back to Raspbian because I wanted the stuff in /opt/vc. I'll see if I can find a link to it.
by ab1jx
Mon Mar 18, 2019 1:34 am
Forum: General programming discussion
Topic: Mixing C and assembly?
Replies: 18
Views: 2233

Re: Mixing C and assembly?

OK, thank you all, this is the sort of stuff I was looking for. I wasn't even quite aware of what an ABI was https://en.wikipedia.org/wiki/Application_binary_interface Relatively recent term, to me. The last time I tried to do much with assembly language was about 1994, I had just taken a C course a...
by ab1jx
Sun Mar 17, 2019 10:35 pm
Forum: General programming discussion
Topic: Mixing C and assembly?
Replies: 18
Views: 2233

Re: Mixing C and assembly?

OK, look at Extended Asm - Assembler Instructions with C Expression Operands The asm statement allows you to include assembly instructions directly within C code. In a GCC PDF or online. But that doesn't answer my question. Here's a printf example: http://www.science.smith.edu/dftwiki/index.php/Tuto...
by ab1jx
Sun Mar 17, 2019 7:29 pm
Forum: General programming discussion
Topic: Mixing C and assembly?
Replies: 18
Views: 2233

Mixing C and assembly?

I found a tutorial http://www.science.smith.edu/dftwiki/index.php/Tutorial:_Assembly_Language_with_the_Raspberry_Pi that does this, but are the rules written down anywhere? What registers you put things into before you call a routine (like printf) and how the returns might work. I was surprised it l...
by ab1jx
Sun Mar 17, 2019 4:13 pm
Forum: Graphics programming
Topic: SPi Display Questions?
Replies: 22
Views: 3352

Re: SPi Display Questions?

So don't load the firmware and find a way to make it work without it. I think that's what OpenBSD is doing, it took years before anybody there got interested in the Pi at all because of the BLOBs. Last I knew they didn't have the HDMI working yet. But there's also NetBSD and FreeBSD. Sounds like the...
by ab1jx
Sun Mar 17, 2019 3:26 pm
Forum: Graphics programming
Topic: SPi Display Questions?
Replies: 22
Views: 3352

Re: SPi Display Questions?

Is there a path from the GPU to HDMI if you do GPU assembly language like Herman Hermitage et al? I'd possibly rather learn that than OpenGL https://github.com/hermanhermitage But yeah, I don't know how it's plumbed. Could be switchable from HDMI to SPI or not, but bit-banging with the CPU mostly ju...
by ab1jx
Sun Mar 17, 2019 7:57 am
Forum: Graphics programming
Topic: SPi Display Questions?
Replies: 22
Views: 3352

Re: SPi Display Questions?

16bpp is the default depth for Raspbian framebuffer and X, so it is enough for 99% of all applications. The framebuffer used to default to 16bpp but I'm sure it's been 32bpp for ages (couple of years or more). I was pleasantly surprised when I wrote this https://sourceforge.net/projects/fbgrad/ but...
by ab1jx
Sun Mar 17, 2019 2:17 am
Forum: Graphics programming
Topic: SPi Display Questions?
Replies: 22
Views: 3352

Re: SPi Display Questions?

I have an old Adafruit 320x240 but even that is too slow with loops in C. A memmove maybe. I was looking for something else and discovered there are now 640x480 LCDs still at 2.8 inches. https://www.dx.com/p/geekworm-raspberry-pi-zero-zero-w-fastest-60-fps-hd-640x480-2-8-inch-touch-screen-display-mo...

Go to advanced search