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  • 07/19/17--19:54: Impact Metrics of a Blog
  • I have a question in regards to the Impact Metrics statistics of written blogs. What is the Global Reach percentage? My apologies if this is not the correct place for this discussion.

     

    Trent


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    Pi Desktop Pi Desktop - Convert your Raspberry Pi into a Desktop PC

    Pi Desktop

    RASPBERRYPI3-MODB-1GB Raspberry Pi 3 Model B with 1GB of RAM

    RASPBERRYPI3-MODB-1GB

    Buy together
    Buy NowBuy Now
    • Intelligent On/Off power switch
    • mSATA SSD socket for up to 1TB on-board storage
    • Integrated RTC (Real Time Clock)
    • Includes case and heat sink
    The Pi Desktop is a desktop computer kit based on Raspberry Pi 2 & 3. It includes a case and an expansion board that can turn a Raspberry Pi into a real desktop PC. It provides an intelligent and safe power controller, a real- time clock, and a high capacity Solid State Drive (SSD) expansion card for additional storage.
    • Add-On board
    • Heat sink
    • USB Adapter (Micro-Type A)
    • Long Spacer (x4)
    • Short standoff (x4)
    • Screws (x2)
    • Enclosure (Base and Lid)
    • Button cell, CR2032
            
    Type Document
    User Manual/Guide Pi Desktop User Manual_EN_Rev3.4 (.pdf)  
    Quick Start Guide Pi_Desktop_QSG_EN_Rev03_Final (.pdf)
              
    Type Download
    Applications Library Pi Desktop Debian File (June 7th, 2017)

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    I recently was trying to do a few things with a Pi3, and it consistently hung when I tried to update the system (sudo apt-get update/upgrade). It did everything else well enough, so I wonder if that's power related, with the upgrade making the WiFi work extra hard - maybe not, but I thought I'd look into it.

     

    I've also noticed that my older Pi1 will hang once in a while (every few months), and that's a bit of an issue now that I'm using it as my sprinkler controller - reliability has become much more important.

     

    While searching for help online, I noticed peteroakes did some research and made a nice blog entry explaining the role the USB cables have in the power issues. (Thanks Peter!)

     

    In a nutshell, some cables cause a voltage drop that puts the supply too far below the ideal 5v voltage level for the Pi.

    The problem is that once in a while the Pi draws enough power to make the voltage dip into the danger zone.

    (Some places sell adapters with a higher voltage to compensate. AdaFruit, for example sells a 5.25v adapter for the RPi, and notes that 5.25v is still within the specifications for USB, so even with a perfect no-loss USB cable that should be safe.)

     

    One notable item, to me, was that the Pi has some serious power dips on a regular basis, regardless of the cables - just that the better supplies+cables start with higher levels at the Pi and the dips don't take it down too far.

     

    So here's my thought - capacitors are supposed to help against dips and spikes, right?

     

    Is there a way to add some really big capacitor at the Pi side to help avoid such dips (and maybe spikes too) ?

     

    I'm thinking VIN-GND with a 1,000+ uF cap? I have one rated 1,000 at 10v, also I see 1,800 at 16v, both should handle 5v-ish well.

     

    Otherwise, maybe splice a USB cable to add the large cap near the micro-USB plug end?

     

    Will that cause trouble? Will it help at all?

     

    Thanks!

    -Nico


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    This post is a preparation for my attempt to generate VGA with a XuLA2 FPGA board.

    I'm generating an image file that I can upload to the board's SDRAM.

    The FPGA will read it from the RAM and convert it into a VGA image.

     

    The example project for the VGA plug-in for the XuLA has an example image.

    The latest loader tool for the board (xsload 0.1.31) doesn't support the format of that file.

    There's an older version of the loader that supports it but doesn't want to run on my pc.

    Not to worry. In this post I convert the image to a supported load format: Intel HEX.

     

    The XuLA FPGA VGA project and the image file are available on the Xess github:
    https://github.com/xesscorp/StickIt/tree/master/modules/Vga/FPGA/PixelVgaTest

     

     

    Preparation - Generate Binary Image

     

    The example image is in a proprietary format. Below are a few lines as exampe

     

    + 10 00000000 7F 2C 7F 2C 7F 2C 7F 2C 7F 2C 7F 2C 7F 2C 7F 2C
    + 10 00000010 7F 2C 7F 2C 7F 2C 7F 2C 7F 2C 7F 2C 7F 2C 7F 2C
    + 10 00000020 7F 2C 7F 2C 7F 2C 7F 2C 7F 2C 7F 2C 7F 2C 7F 2C

     

    10 stands for 0x10 data elements (16 bytes), the second field is the address in ram it has to go, then there's the 16 bytes payload that represent a few pixels of the image.

     

    The easiest path from that file to the somewhat elaborate Intel HEX format is to convert this into a binary file that only contains the pixel data.

    There are existing utilities that can convert bin to Intel HEX.

     

    I made a small c++ utility to grab those pixel bytes from that example and write it to a binary file.

    The fixed filenames, not using a data buffer and the way I did the ascii-hex to number conversion show that I'm in a holiday mood.

     

    //============================================================================
    // Name        : xess_file_converter.cpp
    // Author      : Jan Cumps
    // Version     :
    // Copyright   : copyleft
    // Description : Convert XES images to BIN files
    //============================================================================
    
    
    #include <iostream>
    #include <fstream>
    #include <string>
    #include <sstream>
    
    
    using namespace std;
    
    
    int main() {
    
    
        ifstream inFile("D:\\users\\jancu\\Documents\\elektronica\\xess\\master\\StickIt\\modules\\Vga\\FPGA\\PixelVgaTest\\img_800x600.xes");    ofstream outFile ("D:\\users\\jancu\\Documents\\elektronica\\xess\\master\\StickIt\\modules\\Vga\\FPGA\\PixelVgaTest\\img_800x600.bin", ios::out | ios::binary | ios::trunc);    string subs;    uint32_t uToken = 0U;    char c;    uint16_t uVal;    string line;    while (getline(inFile, line))    {    uToken = 0U;        istringstream iss(line);        while (iss >> subs) {        if (uToken > 2) {        stringstream ss;        ss << hex << uppercase << subs;            ss >> uVal;            c = uVal;            outFile.write(&c, 1);        }        uToken++;         }    }    outFile.close();    inFile.close();
    
    
    return 0;
    }
    

     

    The result is a file that has 800 * 600 * 2 bytes. Checked with the file size:

     

     

     

    Generate Intel HEX File

     

    The sourceforge.net srecord project supports converting binary files into Intel HEX format.

     

     

    srec_cat img_800x600.bin -binary -o img_800x600.hex -intel

     

    The output format generated by the utility is as below:

     

    :020000040000FA
    :200000007F2C7F2C7F2C7F2C7F2C7F2C7F2C7F2C7F2C7F2C7F2C7F2C7F2C7F2C7F2C7F2C30
    :200020007F2C7F2C7F2C7F2C7F2C7F2C7F2C7F2C7F2C7F2C7F2C7F2C7F2C7F2C7F2C7F2C10
    ...
    :20A5C00000000000000000000000000000000000000000000000000000000000000000007B
    :20A5E00000000000000000000000000000000000000000000000000000000000000000005B
    :00000001FF

     

     

    The xsload utility seems (I can't prove it yet because I don't have a VGA cable) to accept the format and load the file to RAM:

     

    xsload  --ram img_800x600.hex

     

    output

     

    Success: Data in None downloaded to RAM on XuLA2-LX25!

     

     

    Success?

     

    I will know that once I connect the kit to a TV. I've checked the VGA output on an oscilloscope.

    I built and loaded the Xess VHDL example (I'll explain the steps in a future blog) and loaded the bitstream:

     

    xsload --fpga pixelvgatest.bit

     

    output

     

    Success: Bitstream in pixelvgatest.bit downloaded to FPGA on XuLA2-LX25!

     

     

    Yellow: HSYNC

    Cyan: VSYNC

    Magenta: one of the video signals

     

     

    I hope to be able to show a TV screen with image soon. Hang on ...

     

    XuLA2 FPGA - First Impressions of the Development Tools
    XuLA2 FPGA - SD Card Read and Write
    XuLA2 FPGA - Rotary Encoder and VHDL
    XuLA2 FPGA - PWM with Dead Band in VHDL
    XuLA2 FPGA - Up the Clock
    XuLA2 FPGA - Utility to Generate Pin Assignments

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    BatteryFreePhone-UW.jpg

    A team of faculty members and students at the University of Washington have developed the first phone that can operate without a battery to power its functions. The phone is made with commercially available components on a printed circuit board. (Photo via University of Washington, you can read the research paper here)

     

    Communication is an essential part of life, and the telephone has likely been the greatest innovation in enabling communication between two remote locations, but ever since the need to speak on telephones went mobile, reliance on batteries can range from a minor inconvenience to a catastrophe. The phone developed by researchers at the University of Washington is a promising development in mobile communication and navigates around the possible perfect storm of an emergency scenario and a dead cell phone. It uses ambient power from surrounding radio signals, as well as from light because it has tiny photodiodes which capture light and convert it into an electrical current.

     

    The user places a call by pressing capacitive touch buttons on the circuit board (which have the same layout as a regular phone), and according to the research team’s video, the phone transmits digital packets back to the cellular network of the base station from which it draws power, and they combine to form a phone number that is dialed using Skype. According to the team’s research paper, in its testing, the phone picked up power from radio frequency signals transmitted by a base station 31 feet away from the phone and was able to place a Skype Call to a base station that was 50 feet away. The team believes that their recent innovation, “...is a major leap in the capability of battery-free devices and a step towards a fully functional battery-free cellphone.”

     

    At this stage in its development, the battery-free phone’s prototype has limited functionality, but it only consumes about 3.5 microWatts of power which is sufficiently supplied by ambient radio waves and light, for the purposes of this research. In Jennifer Langston’s article for UW News, co-author and electrical engineering doctoral student, Bryce Kellogg, is quoted as saying, “...the amount of power you can actually gather from ambient radio or light is on the order of 1 or 10 microwatts. So real-time phone operations have been really hard to achieve without developing an entirely new approach to transmitting and receiving speech.”

     

    According to Langston, the team plans on improving the operating range and encrypting conversations, as well as trying to stream video on a battery-free cell phone by adding a visual display using low-power E-ink screens. This will obviously necessitate more power, and therefore a new approach to supplying the power needed based on the estimates of available power provided by Kellogg. As it stands, the University of Washington team has provided an intriguing proof-of-concept, as well as future directions for exploration and refinement, so now the world must wait to see if their revolutionary invention sparks an even greater change in the culture of mobile communication.

     

    The team’s research was funded by the National Science Foundation and Google Faculty Research Awards.

     

    Watch the video below to see the team demonstrate the operation of their battery-free phone.

     

     

     

    Have a story tip? Message me at: cabe(at)element14(dot)com

    http://twitter.com/Cabe_Atwell


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    2630900-40.jpgThe Pocket IO™ programmable logic controller (PLC) development platform from Maxim Integrated Products, Inc. addresses the challenges of industrial automation and Industry 4.0 designers who need to keep a manufacturing line running 24 hours a day, 7 days a week, and provides you with the ability to achieve the smallest form factor and highest power efficiency for next-generation PLC designs.

     

    The Pocket IO™ programmable logic controller (PLC) development board is a reference design that integrates:

     

    • 30 IO's consisting of four analog inputs, one analog output, eight digital inputs, eight digital outputs,
    • Two RS485 (Profibus-capable field busses)
    • Three encoder motor-control ports
    • Four IO-Link® masters.

     

    Pocket IO connectivity is through USB or its own Wi-Fi® network.

     

    Code can be developed to run on the Intel® Edison using the popular and easy to use open-source Arduino® software IDE.

     

    The Pocket IO provides the following key advantages to increase productivity:

     

    • Real-time intelligence: Fast data processing provides the necessary data to make intelligent decisions quickly and effectively to optimize yield.
    • Adaptive manufacturing: Manufacturing flexibility allows for real-time changes and adjustments to avoid potential downtime.
    • Distributed control: Ultra-small footprint of less than 10 cubic inches and smart energy consumption brings PLC down to the manufacturing line, re-distributing intelligent control and providing redundancy.

     

     

    So, the question is: What prototype would you build with the Pocket IO™ development board? Please offer your comments below


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    Ben, knowing you take large form factor electronics and make them portable, why not do something different and make something small bigger.

    Would love to see a consolized PSP with controller that connected to a tv. I have a psp but was never overly happy with the analog stick and button layout.

    I love watching your show on YouTube, and the modified game consoles are by far my favorites ( I enjoy all your content though.)

    To the people reading this post, reply to this thread with a "heck yeah" to get this made.

    Thanks.


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    I hadn't even realised that we were on to Doug's DIY Test Equipment Challenge and, look, shabaz has finished already with his Cyclops-1000: An Electronic Eye for Rotational Speed Measurement. I bet he's sitting there thinking he's won. We can't let that go unchallenged, so here's my first try. I don't expect it will win; not just because I'm posting it in the wrong place and technically I can't win, but also because I've just thrown it together without all the careful thought and consideration that Shabaz put into his (and I'm not even going to try and match all his fancy graphics).

     

    I proudly present the ByEar 2000. It's a logic probe and its unique selling point is that the output isn't LEDs but rather sounds from a loudspeaker. It's not a new idea (I build something similar back in the 1980s and it wasn't original even then) and you probably don't even need a logic probe anyway but, it's a nice simple circuit, it will cost you hardly anything to build, and it can be the basis for experimenting with comparators even if you don't have boards full of logic to test. (It's 2000 because I reckoned we needed to get some name-inflation into this competition and 2000 is twice as good as 1000, isn't it.)

     

    The other thing about it is that there's no processor and no programming - this is just pure hardware. [Sorry if you were looking forward to seeing me struggle to install IDEs and mangle code into shape - somebody else will have to do that one.]

     

    Here's the circuit diagram

     

    byear-circuit.jpg

    The parts represented by triangles are comparators. Operation of a comparator is quite simple, the two inputs are compared and the output driven depending on which is higher than the other. This part that I've chosen is a quad comparator - that just means that there are four of them in the package and they share the power connections. The LM339 is very low cost and is available in a DIP package, so it's nice to experiment with. One thing you need to know is that I've drawn the circuit using the TI-TINA simulator that's available from TI and that package isn't intended for PCB layout, so each comparator you see on the circuit has been given the same pin numbering (a proper layout package would understand about multiple comparators in a single package and allocate the pin numbers accordingly). I've drawn on the pinning that I used for the prototype.

     

    How does the circuit work? We can consider it composed of two halves. U1 and U2 compare the input to fixed voltages from the potential divider made up of R1, R7, and R8. If the input is below 30% of the supply voltage the output of U2 is set low. If the input is above 70% of the supply voltage the output of U1 is set low. If the input is between those two levels, both outputs are off (they are off rather than high because the output can't go high - it's just the collector of a transistor and the output would only go high if there was a pull-up resistor there). The other half of the circuit is U3 which is working as a relaxation oscillator - this is what is producing the waveform that will be turned to sound by the loudspeaker. The frequency of oscillation is controlled by R2 and a capacitor to ground. In this case, the outputs of U1 and U2 connect either C1 or C2 to ground, so we get a different tone for the high logic level to the low level (the high level sound will be about an octave above the low level sound). When the input is between the logic levels, no capacitor is selected and the output will be silent. For the output, I used a miniature 40 ohm loudspeaker.

    Power comes from the circuit being tested (so the logic levels will relate to that supply voltage). The comparators will operate on anything from 3V up to 30V, so you could even use it with old 4000-series CMOS designs working on voltage rails higher than 5V. The levels here are for CMOS. If you wanted to use it with TTL levels you'd need to adapt it a bit - I'm going to leave that as an exercise for the reader.

     

    Before I built it I tried in in a simulator. Here's the first half - the logic level comparison - with voltmeters to tell us what the output of each comparator is doing.

     

    byear-circuit-comparators.jpg

     

    Here are the waveforms with a triangle wave as an input. You can see how U1 output goes low when it gets above about 3.5V and U2 goes low when it's below about 1.5V. That gives me confidence that it will work when I build it.

     

    byear-waveform-comparators.jpg

     

    Here is the second half - the oscillator. I've just connected it with the 22nF capacitor. There's a voltmeter to measure the voltage across the speaker and an ammeter to show us the current through it.

     

    byear-circuit-oscillator.jpg

     

    Here are the waveforms. The waveform in the middle is computed by the simulator - I just asked it to multiply the volts by the amps to show power. It looks like the average power to the speaker is about 7mW. That's not all that much but we should be able to hear it and it keeps the power consumption of the probe quite low.

     

    byear-waveform-oscillator.jpg

     

    Now for the proof of the pudding. Here's the circuit built on a prototyping block

     

    photo-prototype.JPG

     

    And, finally, here's the video of it beeping just to prove that it works. It's not very good but it will have to do. I'm touching the input (the yellow wire) on to the positive and negative supply wires in turn so you can hear the sound.

     

     

    If you don't like the design decisions I've made then it's simple - change it! The simplest starting point for experimentation is with the two capacitors that set the tone. Try different values and see what happens. If you've got an oscilloscope, maybe probe around the oscillator and see if you can understand what it's doing and why it oscillates. There's also a spare comparator in the package, so there's scope for adding functionality if you think it should be more capable. If you want to experiment further with comparators, download the datasheet here

     

    http://www.ti.com/lit/ds/symlink/lm339.pdf

     

    and you'll see that there are lots of handy circuit suggestions in it there that you can use directly or adapt. Any questions? Ask in the comments and I'll do my best to answer.


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    Pro Perspective: Unleashing BeagleBone Blue

    This webinar will be presented by Jason Kridner, co-founder and board member at BeagleBoard.org Foundation and Open Platform Evangelist with Texas Instruments. Seating is limited, register now!

     

    Tuesday, July 25, 2017 2:00:00 PM EDT - 3:00:00 PM EDT

     

    This is an externally hosted webinar, see below for details.


    Welcome back to the BeagleBone Blue series! There’s nothing more satisfying than seeing your robotics project come to life,
    and we’ll show you how to make it happen with a BeagleBone Blue and Autodesk EAGLE. In this webinar we’ll be walking through
    a complete robotics project, discussing the details of the code, board features, and chassis that all come together to power a robot.
    After attending this webinar you’ll have enough knowledge to start your very own robotics project with a BeagleBone Blue and Autodesk EAGLE.  
    What You’ll Learn:  -Learn about coding your own robotics project and how Linux handles encoders. -Learn about the motor drivers on a BeagleBone Blue and
    how to mount them on a chassis. -Learn how to interface with your BeagleBone Blue to control motor speed and process data.

     

     

    Speaker
    jason-kridner

    Jason Kridner, Co-founder and board member at BeagleBoard.org Foundation and Open Platform Evangelist with

    Texas Instruments and is currently defining the strategy for growing TI’s open platform ecosystem of developers and customer base.

     

    Register for this event here:

    https://eagle-support.adobeconnect.com/ed5mftk4ku4y/event/event_info.html

     

    This event is hosted externally by BeagleBoard.