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by Gavinmc42
Wed May 01, 2019 8:40 am
Forum: Networking and servers
Topic: 1 Watt server challange!
Replies: 67
Views: 2865

Re: 1 Watt server challange!

What ever the minimum serving time is, ie 1ms them the current sampling frequency needs to be about 3KHz or more. Multimeters are not fast enough as they use a dual slope ADC which is much slower. Super caps have charge and discharge voltages that will vary if you want to smooth out the current. You...
by Gavinmc42
Wed May 01, 2019 12:21 am
Forum: Bare metal, Assembly language
Topic: Run Raspbian on 3 cores, Arduino-ish on fourth core?
Replies: 13
Views: 1071

Re: Run Raspbian on 3 cores, Arduino-ish on fourth core?

A Zero based Arduino? Well Arduino uses C++. But what to run it on, the Arm core or the VC4. If video is not needed can the VC4 be used? It is already running a ThreadX RTOS. This is running on one of the Vector Processing Units? What is the other one doing? Ultibo is the easiest way I know to play ...
by Gavinmc42
Tue Apr 30, 2019 2:23 am
Forum: Raspbian
Topic: Optimize 3b+ for use as a casual desktop
Replies: 15
Views: 1158

Re: Optimize 3b+ for use as a casual desktop

Wonder if you use a smaller screen like the Pi 7" 800x480 YT should be faster?
Portable YT viewer?
Good app for a 3A+? Or will 1GB be needed?
I will have to try this, on a FHD 1920x1080 it used to be slow.
by Gavinmc42
Mon Apr 29, 2019 11:58 pm
Forum: Networking and servers
Topic: 1 Watt server challange!
Replies: 67
Views: 2865

Re: 1 Watt server challange!

I use i2c high side current ADCs.
Log the current 100+ times per sec and then average.
It's not perfect but better than any multi meter.
Very useful for RF devices that have low duty cycles.

You could make a webserver that displays it's own power usage ;)
by Gavinmc42
Mon Apr 29, 2019 11:51 pm
Forum: Beginners
Topic: Controlling temperature chamber using Peltier and PWM signal with external power source
Replies: 26
Views: 899

Re: Controlling temperature chamber using Peltier and PWM signal with external power source

Why use a Peltier? It is only 50C, a wirewound resistor or even some nichrome wire will work better. I use wirewound resistors and fans in a DNA PCR that cycles between 55 - 95C. I found out the hard way temperature cycling a bunch of PN silicon junctions squashed between two heatsinks eventually fa...
by Gavinmc42
Mon Apr 29, 2019 2:03 am
Forum: Raspbian
Topic: Optimize 3b+ for use as a casual desktop
Replies: 15
Views: 1158

Re: Optimize 3b+ for use as a casual desktop

Try Gentoo64. It has the fastest Chromium and Firefox response I know of on Pi's. Generally becuase Sakaki keeps it more upto date than Raspbian which is based on an older but stable version of Linux. Sakaki has been working on a dual Raspbian that is not bad. These browsers are my benchmarks progra...
by Gavinmc42
Sun Apr 28, 2019 1:14 am
Forum: Networking and servers
Topic: 1 Watt server challange!
Replies: 67
Views: 2865

Re: 1 Watt server challange!

Duty cycle is a consideration. A Zero W might be using 1.5W when transmitting but if only doing that for 25% of the time then an average would be around 1W? A B+ with Ethernet would be around the same? A SD card would use lower power than a SSD or USB stick? No need for HDMI so that part of the SoC ...
by Gavinmc42
Sat Apr 27, 2019 3:19 am
Forum: Arch
Topic: https://forum.manjaro.org/t/manjaro-arm-19-02-released/75594
Replies: 49
Views: 5242

Re: Manjaro dropping ARMv7 support

but I am really struggling to workout why an unstable 64bit repo is not already under the raspberry namespace. You need to read more posts, there is a 64bit Raspbian Debian for Pi's. It is being worked on, but it is not stable enough yet? About mid year it has been suggested for release. There are ...
by Gavinmc42
Sat Apr 27, 2019 3:01 am
Forum: Networking and servers
Topic: 1 Watt server challange!
Replies: 67
Views: 2865

Re: 1 Watt server challange!

A Zero with serial port SLIP based Ethernet? A Ethernet module based on a 28J60 uses 160ma at 3.3V transmitting , 120ma active. It could save a bit of power waking up the Zero with the interrupt output pin. But a server is not a server unless serving data. So Zero on and transmitter active. I have y...
by Gavinmc42
Fri Apr 26, 2019 8:38 am
Forum: Off topic discussion
Topic: Microsoft buys Express Logic
Replies: 9
Views: 655

Re: Microsoft buys Express Logic

If you cannot beat them, buy them?
Amazon/FreeRTOS, Microsoft/ThreedX.
IoT is getting very interesting.

FreeRTOS is open source?
ThreadX is not?

So Pi's will have MS code inside them from now on ;)
Time will tell if this makes a difference to the IoT market.
by Gavinmc42
Fri Apr 26, 2019 5:47 am
Forum: Networking and servers
Topic: 1 Watt server challange!
Replies: 67
Views: 2865

Re: 1 Watt server challange!

PiCore Linux with busybox httpd is the smallest Linux server I have done. Ultibo webserver example is the smallest that I have made to work. Both of these leave plenty of room on a SD card Harder to go lower power as both WiFi or Ethernet do take a bit of power. About 120ma at 3.3V, about 1/2W. This...
by Gavinmc42
Fri Apr 26, 2019 5:32 am
Forum: Arch
Topic: https://forum.manjaro.org/t/manjaro-arm-19-02-released/75594
Replies: 49
Views: 5242

Re: Manjaro dropping ARMv7 support

Zero's work extremely well if you use baremetal or tiny headless Linux OS's. For the price and support nothing else comes close. Big bloated Desktop Linux is NOT compulsory, the limitations allows for exploring other options. It is a 32bit 1GHz CPU with 512MB of Ram, why does it need to run Chromium...
by Gavinmc42
Fri Apr 26, 2019 2:44 am
Forum: Automation, sensing and robotics
Topic: Is the Raspberry Pi suitable for this project? (Solar Tracking a PTC)
Replies: 5
Views: 267

Re: Is the Raspberry Pi suitable for this project? (Solar Tracking a PTC)

Personally being a Grad project I would use a Pi, and log the crap out of the rig, Yep, that's what I use Pi's for. It is kind of cool ssh-ing into a Pi 100km away or the next building's roof and changing shell script on the fly :D Once you get used to "Cron' it is so useful. For shorter time frame...
by Gavinmc42
Thu Apr 25, 2019 7:08 am
Forum: Beginners
Topic: Build/Buy 128 Button Matrix
Replies: 18
Views: 537

Re: Build/Buy 128 Button Matrix

Reading about DIY keyboard, one thing they mention is N key roll over. ie how many keys the scanning system can read at one time. For a Piano this would be 10 keys at least. A PC gamer might regard 8 keys as good ;) Some key scan systems use diodes to stop pressed keys affecting the scanning of othe...
by Gavinmc42
Thu Apr 25, 2019 2:25 am
Forum: Off topic discussion
Topic: is the pi worth it?
Replies: 103
Views: 6100

Re: is the pi worth it?

I recently start playing with tcl/tk, been ignoring it because it was so old. But because of that it works on all OS's. So learning it on Pi's means it can be used on Windows and big Linux PC's too. Python is OK but higher level languages take a fair bit of work to get something graphic and reactive...
by Gavinmc42
Thu Apr 25, 2019 2:12 am
Forum: Beginners
Topic: Build/Buy 128 Button Matrix
Replies: 18
Views: 537

Re: Build/Buy 128 Button Matrix

Note we are talking about music keyboards here, not PC or typewriter-style keyboards, though the key scanning will likely have much in common. Whoops missed that :oops: That is more than just switches. Perhaps linear hall effect switches? Musical instruments keys have attack rates measured, google ...
by Gavinmc42
Thu Apr 25, 2019 1:52 am
Forum: Automation, sensing and robotics
Topic: Is the Raspberry Pi suitable for this project? (Solar Tracking a PTC)
Replies: 5
Views: 267

Re: Is the Raspberry Pi suitable for this project? (Solar Tracking a PTC)

I've never thought of using an analog tracker circuit! How much knowledge do you need to understand those circuits though? You only need to know how to google the right words ;) https://www.electroschematics.com/8019/diy-solar-tracker-system/ Much simpler than trying to learn Python ;) TMP112 and T...
by Gavinmc42
Wed Apr 24, 2019 11:39 am
Forum: Beginners
Topic: Build/Buy 128 Button Matrix
Replies: 18
Views: 537

Re: Build/Buy 128 Button Matrix

Have a look at DIY keyboards, lots of people are doing it now. https://medium.com/@monkeytypewritr/building-your-own-keyboard-from-scratch-bd0638c40850 https://mechanicalkeyboards.com/shop/index.php?l=product_list&c=47 Plenty of code examples for Arduino or Teensy? Let the Arduino do the hard stuff ...
by Gavinmc42
Wed Apr 24, 2019 12:31 am
Forum: Automation, sensing and robotics
Topic: Is the Raspberry Pi suitable for this project? (Solar Tracking a PTC)
Replies: 5
Views: 267

Re: Is the Raspberry Pi suitable for this project? (Solar Tracking a PTC)

The Pi can do it, bit of an overkill unless you want to log data with it as well. A parabolic trough would only need tracking in one axis? A Pi and Arduino are both overkill, a simple analog tracker can be made without the need to code anything. Google should find plenty of circuits. My first use of...
by Gavinmc42
Tue Apr 23, 2019 10:31 am
Forum: General discussion
Topic: New Raspbian release 8th April 19
Replies: 21
Views: 1143

Re: New Raspbian release 8th April 19

Never really noticed it before and I must have downloaded for there many, many times. Release notes back to 2013 :o But hey, who RTFM's anyway? And yes please, a sarcasm smilie would be nice, insert one here ? I guess sarcasm is a lost art like political satyr cartoons? Hmm, have I turned into Dilbe...
by Gavinmc42
Tue Apr 23, 2019 9:09 am
Forum: Arch
Topic: https://forum.manjaro.org/t/manjaro-arm-19-02-released/75594
Replies: 49
Views: 5242

Re: Manjaro dropping ARMv7 support

They just cannot be arsed to support it. What version is Chromium up to 72, 73? Not sure how big their testing department is but something that big would be a pain to test? And doing it 72 times for how many architectures? Manjaro would have less developers than Google? Lucky it is based on Arch, s...
by Gavinmc42
Tue Apr 23, 2019 8:21 am
Forum: Beginners
Topic: Build/Buy 128 Button Matrix
Replies: 18
Views: 537

Re: Build/Buy 128 Button Matrix

A recent mini Pi Zero terminal PCB used a Ti chip, TCA8418. This is an i2c keypad scanner that handles the scanning of 80 keys. https://liliputing.com/2019/03/this-10-pcb-lets-you-build-a-handheld-pc-with-a-raspberry-pi-zero-w-plus-a-display.html TCA8330, TCA8333 are similar. An Arduino could probab...
by Gavinmc42
Tue Apr 23, 2019 4:23 am
Forum: Arch
Topic: https://forum.manjaro.org/t/manjaro-arm-19-02-released/75594
Replies: 49
Views: 5242

Re: Manjaro dropping ARMv7 support

We really need to put an end to this persistent and pervasive myth that 64-bit data or 64-bit addressable memory can only be used by 64-bit architectures. I think it has more to do with the issue that code bloat is now so big that it is too hard to support 32bit cpus. Too much testing and debugging...
by Gavinmc42
Mon Apr 22, 2019 7:37 am
Forum: Arch
Topic: https://forum.manjaro.org/t/manjaro-arm-19-02-released/75594
Replies: 49
Views: 5242

Re: Manjaro dropping ARMv7 support

And Raspberry Pi 3 probably will never get GPU acceleration on mainline, because they don't contribute much of their code upstream.
No GPU acceleration?
by Gavinmc42
Mon Apr 22, 2019 7:24 am
Forum: Arch
Topic: https://forum.manjaro.org/t/manjaro-arm-19-02-released/75594
Replies: 49
Views: 5242

Re: Manjaro dropping ARMv7 support

Aarch64, ARMv8 only?
64bit only OS's have been the writing on the wall for some time.
This one I have not tried, looks pretty.
Is it fast enough on a 3B+?

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