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by MarkTF
Fri Aug 04, 2017 6:13 pm
Forum: General discussion
Topic: Raspberry Pi High Voltage Parallel Programmer
Replies: 6
Views: 912

Re: Raspberry Pi High Voltage Parallel Programmer

A bit of a nitpick...none of those links expands the "AVR" acronym, and there are multiple uses of said acronym. (And, for that matter, from my own experience, "AVR" is "Automatic Volume Recognition", but I'm *sure* that isn't the usage you mean.) "Atmel says that the name AVR is not an acronym and...
by MarkTF
Mon Jul 31, 2017 2:59 pm
Forum: General discussion
Topic: Legally extending Zero WiFi?
Replies: 10
Views: 2023

Re: Legally extending Zero WiFi?

Parabolic dish antenna systems use a moderately directional feed antenna that directs it's energy at the dish which focuses it into a tighter beam. The technical issue with simply putting a Zero at the feed point of a dish is that with its nominally omnidirectional antenna, most of the energy misses...
by MarkTF
Mon Jul 24, 2017 8:34 pm
Forum: General discussion
Topic: processing 3.3.5
Replies: 19
Views: 2119

Re: processing 3.3.5

I'd try plotting the FFT output in Processing to see if three lowest frequency bins are consistent with what you're seeing on the LED matrix display. My guess is that they are and that your problem is low frequency noise on digitized audio, perhaps a ground loop or power supply isolation problem. Al...
by MarkTF
Sun Jul 23, 2017 1:26 pm
Forum: General discussion
Topic: processing 3.3.5
Replies: 19
Views: 2119

Re: processing 3.3.5

Let me be more direct. You need to post your code if you expect help debugging it.
by MarkTF
Sat Jul 22, 2017 3:48 pm
Forum: General discussion
Topic: processing 3.3.5
Replies: 19
Views: 2119

Re: processing 3.3.5

If the Processing code you haven't shown us doesn't do so automatically, you'll have to change the USB serial device to whatever the RPi is using. Otherwise the code on the RPi should be the same as on the PC. The Arduino side won't change.
by MarkTF
Thu Jul 20, 2017 7:38 pm
Forum: General discussion
Topic: Spectrum Analyzer
Replies: 14
Views: 6661

Re: Spectrum Analyzer

I'm sure a Pi is plenty fast enough to run an FFT for an audio spectrum analyzer driving any normal kind of bargraph display. I'd expect the Arduino is fast enough to run an FFT for that display resolution and one doesn't even need the RPi. It wouldn't be continuous samples, rather fill sample buff...
by MarkTF
Tue Jul 04, 2017 8:35 pm
Forum: General discussion
Topic: Integrating Raspbian with Android The Matrix Way
Replies: 5
Views: 1022

Re: Integrating Raspbian with Android The Matrix Way

It is possible to chroot under Android and run a Linux system. See "Linux Deploy" on the Android App Store. It's unlikely you will be able to boot a Raspbian image, but you should be able to bring up a Debian or similar environment. Whether your application will run under that is a question of the d...
by MarkTF
Fri Jun 23, 2017 2:23 pm
Forum: General discussion
Topic: Free ram [solved]
Replies: 34
Views: 4632

Re: Free ram

I do not own one.. if i could know it across all models from people who own some.. then i could choose the best one for me. :oops: :oops: To make any sense of this, wouldn't you have to know how much RAM is required for your application? The RPi3 is the most capable model in the best supported line...
by MarkTF
Wed Jun 14, 2017 1:29 pm
Forum: General discussion
Topic: remote desktop access VNC from ubuntu running on virtualbox
Replies: 2
Views: 782

Re: remote desktop access VNC from ubuntu running on virtual

In the absence of details, I believe that VirtualBox does not connect the virtual machine to the VirtualBox host's network by default. If you open a command terminal on the Pi and on the Ubuntu VM and type "ip a" in each, this will display the network connections. My expectation is that the two don'...
by MarkTF
Tue Jun 06, 2017 3:05 pm
Forum: General discussion
Topic: Access pi via USB
Replies: 9
Views: 8250

Re: Access pi via USB

Does Raspbian boot up with an interactive serial console configured by default on the gpio pins that constitute the on-board UART? Yes it does. This is the way I would approach this problem. It's also a convenient way to set up a headless RPi. See, for instance: http://elinux.org/RPi_Serial_Connect...
by MarkTF
Sun Jun 04, 2017 4:19 am
Forum: General discussion
Topic: Simple battery circuit feasible?
Replies: 16
Views: 2322

Re: Simple battery circuit feasible?

As previous posters have noted, 3.7 V implies you're using LiPo batteries. The usual charge algorithm for LiPo batteries is constant current to a particular voltage and then constant voltage until the current goes down to a specified level. The implication is that the voltage and current into the ba...
by MarkTF
Tue May 30, 2017 4:48 pm
Forum: General discussion
Topic: Why are ARMv6 CPUs still sold in the newest RPi models?
Replies: 21
Views: 2511

Re: Why are ARMv6 CPUs still sold in the newest RPi models?

The BOM of the Pi0W is clearly cost sensitive and this, no doubt, drives the SOC selection. Regardless, even if the Pi0W used a newer core, a software developer would be faced with the same dilemma if they wished to maintain compatibility with the millions of BCM2835 based boards already out there. ...
by MarkTF
Tue May 23, 2017 4:30 pm
Forum: General discussion
Topic: Sonic Pi Theremin
Replies: 4
Views: 617

Re: Sonic Pi Theremin

Given that a theremin is broadly an electronic instrument played by waving one's hands in the air, I'm guessing this device uses an ultrasonic rangefinder as a sensor to detect hand movement. Since it is ubiquitous, I'm also going to guess that the sensor is an HC-SR04*. Finally, since the sound out...
by MarkTF
Thu May 11, 2017 4:25 pm
Forum: Off topic discussion
Topic: Recommendations for a good, but cheap, multimeter
Replies: 28
Views: 13616

Re: Recommendations for a good, but cheap, multimeter

In the US, we have Harbor Freight, whose business model seems to be selling cheap Chinese tools. When the local store opened a few years back they were mailing advertisements with coupons for free stuff just to get people into the store and I built a collection of 4 (?) multimeters like that shown b...
by MarkTF
Sat Apr 22, 2017 2:07 pm
Forum: General discussion
Topic: Old PC with Debian with pixel x86
Replies: 13
Views: 2106

Re: Old PC with Debian with pixel x86

Linux didnt seem particularly fast on the machine and kept freezing. Were you running Linux from a hard disk install or from a USB stick? If the latter, then I've seen "long pauses" due to the USB drive speed. I've also seen cases where Linux doesn't support graphic acceleration on some hardware. I...
by MarkTF
Fri Apr 21, 2017 3:08 pm
Forum: General discussion
Topic: Broken Galaxy to powerful Rasberry pi
Replies: 4
Views: 769

Re: Broken Galaxy to powerful Rasberry pi

Hey does anyone know if I can turn my old Galaxy S6 Active into a pi? Only the screen is broken You can't turn it into a Pi. It may be possible to root the phone and install some version of Linux using the "Linux Deploy" app. This effectively turns your phone into a standalone ARM Linux computer ca...
by MarkTF
Fri Apr 21, 2017 2:38 pm
Forum: General discussion
Topic: Old PC with Debian with pixel x86
Replies: 13
Views: 2106

Re: Old PC with Debian with pixel x86

would lubuntu have to be installed to hard drive or would it run from a USB stick? It seems the optical drive is knackered I've set up systems that run from a USB stick*, but typically would install to the hard drive. Since Lubuntu, like most current Linux distributions are larger than a CDROM, the...
by MarkTF
Fri Apr 21, 2017 2:11 pm
Forum: General discussion
Topic: Old PC with Debian with pixel x86
Replies: 13
Views: 2106

Re: Old PC with Debian with pixel x86

I've used Lubuntu, the (Debian based) Ubuntu distribution with the LXDE desktop, for precisely this purpose on a number of old computers*. It has the advantage of being a very well supported and mature distribution with regular updates and it is as easy to install and get running as anything you are...
by MarkTF
Thu Apr 06, 2017 3:53 pm
Forum: General discussion
Topic: Try to perform GPU_FFT with Audio Sound card
Replies: 14
Views: 1837

Re: Try to perform GPU_FFT with Audio Sound card

California wrote:Hello, would anybody be so kind to describe what should be done to use gnuplot with python on Raspbian?
Python "matplotlib" might be a better way to go if for no other reason that it's easier to find documentation and examples.

http://matplotlib.org/
by MarkTF
Thu Apr 06, 2017 1:47 pm
Forum: General discussion
Topic: Overheating dangers between RP2 vs RP3
Replies: 27
Views: 2676

Re: Overheating dangers between RP2 vs RP3

All you have to do is consider smoking. Think of how many decades it took to unravel that. (And then how many decades after that it took to become common knowledge - that is, accepted by the man-on-the-street - which is to say, this has only happened within the last 5-ish years). Think of how much ...
by MarkTF
Thu Apr 06, 2017 1:26 pm
Forum: General discussion
Topic: Is the RPi "just" an educational tool ?
Replies: 61
Views: 6140

Re: Is the RPi "just" an educational tool ?

My impression of that is it mostly comes from those eager to defend RPT/RPF decision making who wish to show their loyalty and support for the RPT/RPF in dismissing requests for change. My impression is that there is a great deal of engineering experience represented on this board that has grown we...
by MarkTF
Wed Apr 05, 2017 2:44 pm
Forum: General discussion
Topic: Is the RPi "just" an educational tool ?
Replies: 61
Views: 6140

Re: Is the RPi "just" an educational tool ?

The RPi is clearly not just an educational tool. Even so, the RP Foundation views education as it's principle mission and will rightly base product planning and investment biased toward that mission. Thus the Foundation is unlikely to tack on features that which fail a cost/benefit analysis viewed t...
by MarkTF
Tue Mar 28, 2017 1:26 pm
Forum: General discussion
Topic: First time buyer. Recommendations?
Replies: 8
Views: 851

Re: First time buyer. Recommendations?

. . . Things like cables are safe to buy off ebay. Critical components are too valuable. . . The USB power cable (and power brick) is a critical component. One can get a good quality cable (explicitly specified as 28/24 gauge (24 gauge power wires)) off of eBay or Amazon, but if you get the cheapes...
by MarkTF
Sat Mar 25, 2017 8:51 pm
Forum: General discussion
Topic: Raspberry boards based on x86 SOC
Replies: 72
Views: 16224

Re: Raspberry boards based on x86 SOC

There are, and have been for years (decades really), a wide variety of Intel-based single board computers available on the market. If that's what you want, I wish you the best. They do make sense in certain applications and I've used some myself.
by MarkTF
Fri Mar 17, 2017 4:41 pm
Forum: General discussion
Topic: Portable DAB radio?
Replies: 2
Views: 4710

Re: Portable DAB radio?

There is a complete set of instructions for doing this via RTL-SDR here: http://www.michaelcarden.net/?p=48

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