Posts Tagged ‘power’

Convert an old ATX Power Supply into a Bench Power Supply with (or without) 3D Printed Parts

June 16th, 2017 15 comments

You may own one or more old computer towers with an ATX power supply that just gather dust, but since the ATX connector provides +12V, -12V, 5V, 3.3V and GND signal it could be converted into an bench power supply. People have been doing this for a while, but elliotboney’s solution looks neater than most with a 3D printed part that’s attached on top of the power supply.

Once you have printed the part, which may need to be adapted to to your power supply, you just need a few banana jacks, and a power switch before connecting with the cables:

I basically kept 3 wires of each voltage, a 3 black wires for each ground. So 3 yellow for 12V, 3 Red for 5V and 3 Orange for 3V. Any extra wires I cut as close to the board as possible and put a little piece of heat shrink over the cut wires just to prevent shorts.

For the switch, you’ll use the green wire and a ground. Internally, you’ll want to connect the gray wire and an extra 5V (red) wire. This is the power_ok to let the PSU know it’s outputting the correct voltage.

That post clearly explains ATX to bench power supply conversion in details, and provides a ATX connector pinout diagram.


Once all the connections are done, the back of the 3D printed part looks like that:

Via Adafruit Blog.

Categories: Hardware Tags: 3d printing, power, recycle

ARM Chromebooks Run Android Apps Better, Exhibit Longer Battery Life than Intel Chromebooks (Study)

May 24th, 2017 4 comments

Google has been working on supporting Android apps and the Play Store on Chromebooks, which are normally sold with either ARM or Intel processors. So the ability to run Android apps well is one of the things to consider before purchasing a Chromebook. Shrout Research has published a paper entitled “Chromebook Platform Choice Important for Android App Performance” comparing an Acer Chromebook R13 with a Mediatek MT8173C ARM Cortex A72/A53 processor to Acer Chromebook R11 with an Intel Celeron N3060.

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The Intel Chromebook has a smaller resolution so this could be an advantage, so less resources are needed to update the display. However, the ARM processor is significantly more powerful than the Intel one according to GeekBench results, and Chromebook R13 is sold for $399 on Amazon US, while Chromebook R11 goes for $299 (and lower during promotions). So it’s not a perfect comparison, but it should give an idea especially when it comes to app stability.

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The ARM Chromebook can run Android apps “well” (only minor issues) and “very well”, while the Intel Chromebook also did a good job for entertainment and productivity apps, but performed unreliably, and in some cases very poorly with some social media apps, and games. Since most mobile phones are based on ARM, developers spent more time optimization code for the platform. Some performance issues may also be partially due to different CPU and GPU performance, but the study did not address this at all, except when saying R11 screen resolution was lower.

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The research company also ran “education simulation” in both Chromebooks, not using Android apps, but instead various website and apps in the web browser such as Edmodo, Google Docs, Solar Explorer, etc… and found out the Intel chromebooks was depleting the battery faster with the ARM Chromebook uses 11.5% less power.

One last point shown in the disclaimer at the end of the paper:

This paper was commissioned by ARM Holdings. All testing, evaluation and analysis was performed in-house by Shrout Research and its contractors. Shrout Research provides consulting and research services for many companies in the technology field, other of which are mentioned in this work

Via Brent Sullivan on G+

$59 HDFury Universal PSU Doctor Supports Power Monitoring via iOS or Android

May 3rd, 2017 4 comments

We’ve recently covered Cambrionix PowerPad 15S, a high-end 16-port USB hub that can deliver 5V/2.1A on each port, integrates power monitoring function, and an API to control and monitor each port individually. That’s a very cool device, but it’s also expensive at around $600, and even the cheaper PowerPad 15C without data pins, come at $200. If you don’t need the complete set of features offered by Cambrionix devices, but you’ll like to get a reliable multi-port USB charger with power monitoring function, HDFury Universal PSU Doctor could be an interesting option.

HDFury Universal PSU Doctor specifications:

  • MCU – Renesas RL78 16-bit MCU
  • USB – 3x USB ports with 2x 5V ports up to 5V/2.14A, 1x USB QC 2.0 port supporting 5V/2.14A, 9V/1.6A or 12V/1.2A output
  • ADC – Up to 11 channels, 10-bit resolution for power monitoring
  • Sensor – n-chip temperature sensor
  • Power Supply
    • Built-in 100 ~ 240V AC with US, EU, UK plug types (Sorry Australian readers).
    • Ripple and Noise: 80mV
    • Efficiency: 80%
  • Power Consumption @ 5V?
    • Stop – RAM retained: 0.23 μA; LVD enabled: 0.31 μA
    • Snooze – 0.7 mA (UART), 1.20 mA (ADC)
    • Operating: 63 μA /MHz
  • Dimensions – 8.9 x 5.3 x 4.2 cm.
  • Weight – 142g
  • Certifications – Rohs, CE and FCC (no UL / ETV / TUV?)

Click to Enlarge

The first two USB ports (1 & 2) can handle 5V, and the first one can connect to a smartphone audio jack to report the voltage, current, and power for all three USB ports. The third port also supports Quick Charge 2.0.

Power monitoring is done through DrPSU app available for Android and iOS, but note that it’s expected to work only on branded smartphones such as Samsung, LG, Sony, Xiaomi, Apple… and obviously this feature won’t work on the most recent models without an headphone jack since it is required. The app cannot control the USB port individually, for example to turn them on and off, it only displays the data. The video below demonstrates well how it all works.

HDFury Universal PSU Doctor is sold for $59 with free shipping on HDfury website. There’s a 5-year warranty, but you’d have to return the charger to China, and I could not find the warranty’s terms and conditions.

Selecting a Micro USB Cable to Power Development Boards or Charge Phones

April 27th, 2017 13 comments

Yesterday one person contacted me on Facebook asking me whether there was any chance of me doing a “which usd-micro usb cable is best”, as there’s not much clear information on the Internet. His purpose was to charge his phone, but many development boards come with a micro USB port, and I’ve read many comments about powering the board. It also happened to me, and the main cause can either be the power supply which does not work as rated (usually 5V/2A), or the micro USB cable which may have a resistance a little to high leading to voltage drops. You’ll know you may have a power problem when the board refuses to boot, and usually boot loop, or randomly reboots especially under high load. The first solution is to get a power supply that provide the right voltage and amperage, and you can test that with USB Charger doctor an ultra cheap tool that will show both the voltage and intensity on an LCD display, although it will only work on chargers with a USB port.

But what about the micro USB cable? Let’s consider the actual problem, which is well explained in a post about USB cable resistance, but I’ll summarize below. First all conductor have some tiny resistance, and usually the thicker the cable the less resistance there is. The American Wire Gauge (AWG) value is often used to describe the thickness of the cable, with numbers from 0 to 40 ranging from the larger diameter/smaller resistance/higher capacity to the smaller diameter/larger resistance/lower capacity. For USB cable, AWG20 to AWG28 are often used for USB cables, and the latter seems to be very common for  data wires, but what matters here is the AWG value for the power wires (5V/GND) of the cable. The resistance also depends on the length of the cable with longer cables having a longer resistance, as well as the USB contact resistance, but I’m not sure we can do much about that one. Anyway, that means a short cable with a lower AWG value would be better suited here, as shown in the table below from the aforelinked post using 5V/1A and 5V/1A loads. This table assumes 30 mOhms contact resistance, so the values would be lower if there’s a lower resistance.

Boards can normally work in a range around 5V. For the sake of argument, let’s assume a board taking 4.5V to 5.5V DC input. and would reboot if the voltage drops below 4.5V. If you have a 5V power supply use with a non-optimal AWG rating and length, the voltage will drop more than 0.5V (red zone above) and the board will not work properly. 5V/1A (5W) is a very common on development boards, while getting to 10Watts is possible for you’d need a high load plus possible some USB storage device to reach the power level.

Based on those results, what we want is an AWG20 cable (ideally) with a length of less than one meter, and the shorter the better. So I’ve been looking for such cables on the web and found a bunch. I did not test any, but they may be good candidates to look at:

There are many others, just search for AWG20 micro USB cable, or in some cases micro USB charging cables, and you should find decent cables that should not cause power or charging troubles. The last cable in the list above (eBay) was tested with a Charger Doctor dongle showing 4.95V/3.47A going through the cable (1.8 meter length). The voltage value should be lower when measured at the DIY charging board due the internal resistance of the cable, but it still shows the cable allows around 3 to 4 amps.

Toaster Breadboard Power Supply Supports 3.3V, 5V, and Variable 5V to 16 V Outputs

March 23rd, 2017 3 comments

YwRobot MB102 is a popular power supply for breadboards delivering 5V or 3.3V to both power rails. Bradsprojects’ Toaster power supply offers similar functionalities but beside outputting just 5V or 3.3V, it also adds a 5V to 16V variable output, and takes 5V from its micro or mini USB port.Toaster board specifications:

  • Input Voltage – 5V via USB Mini and USB Micro port
  • Input Current (max) – 1Amp
  • Output Voltage 1 – 3.3 Volts
  • Output Voltage 2 – 5 Volts
  • Output Voltage 3 – Variable 5 Volts to 16 Volts with potentiometer
  • Protection – 1.1Amp Resettable Fuse
  • Output Connection – Standard Dual Rail Breadboard 2.54mm spacing.
  • Dimensions – 50mm x 25mm

You just need a screwdriver and a multimeter to adjust the variable output to your requirement.The Toaster board can be purchased on Tindie for $10 + shipping.

Categories: Hardware Tags: electronics, power

Atomo is a Raspberry Pi Compatible Modular Electronics Prototyping System (Crowdfunding)

March 22nd, 2017 7 comments

Atomo is a modular electronics protyping system comprised of four elements: Control, I/O, Power, and Connector, with the PCBs for each category color-coded with respectively red, blue, green, and black. The connector board connects power, I/O and control(ler) boards together in a way that’s supposed to be neater than most hand made prototypes.

The whole ecosystem includes 15 different boards:

    • Controllers with 26-pin Raspberry Pi compatible header
      • 2 IO Module Controller (CM-M2K22-A) based on NXP Kinetis K22F MCU
      • 4 IO Module Controller (CM-M4K64-A) based on NXP Kinetis K64F MCU
      • 8 IO Module Controller (CM-M8K64-A) based on NXP Kinetis K64F MCU

        2 IO and 8 IO Controller Boards – Click to Enlarge

    • Connectors
      • 8 IO Module Connector (GM_M8P2_A) – Dim: 145mm x 100mm; power up to 40V @ 64A
      • 4 IO Module Connector (GM_M4P1_A) – Dim: 71mm x 100mm; power up to 40V @ 32A
      • 2 IO Module Connector (GM_M2P1_A) – Dim: 71mm x 65mm; power up to 40V @ 16A
      • 2 IO Module Low-Power Connector (GM_M2P0_A) – Dim: 71mm x 65mm; Good for low power 5V/3.3V designs

        8 IO Modules Connector Board

    • IO Boards
      • Single Stepper Driver with Sensing IO Module (IO-001ST1-A)
      • Triple Stepper Driver with Limits IO Module (IO-002ST3-A)
      • Single Stepper and Heater Driver with Limits and Dual Temp (Thermistor + Thermocouple) IO Module (IO-003ST1TC1-A)
      • Single Stepper and Heater Driver with Limits and Dual Temp (2x Thermistor) IO Module (IO-003ST1TH1-A) with ADC, I2C, SPI, PWM

        Atomo IO-003ST1TH1-A – Click to Enlarge

    • Power Boards
      • 1X ATX Power Module (PM-ATX1X-A) for 1 ATX power supply with support for 3.3V, 5V, 12V plus a higher voltage up to 40V @ 32A
      • 2X ATX Power Module (PM-ATX2X-A) for 2 ATX power supply with support for 3.3V, 5V, 12V plus a higher voltage up to 40V @ 64A
      • 10A 5.5mm Barrel Plug Power Module (PM-VIN10A-A) – Input from 15V, 2A up to 24V 10A. Output: 12V, 5V, and 3.3V
      • 13W POE Power Module (PM-POE13W-A) – Output 12V, 5V, and 3.3V; network data passthrough; auxiliary 5.5mm barrel plug 12V output.

        2x ATX Board

They also have one expansion module with USB input & UART headers, a USB port, an Ethernet port, and a 26-pin header, which you can use if you don’t connect the controller board to a Raspberry Pi.

So now, you have to decide about your project’s power and IO requirements, select the boards, and put it all up together.  That’s what it looks like when the Raspberry Pi comes into play together with four IO modules and one ATX power board.

Now you’ll need to program the NXP Kinetis based controller board using  KDS and MCUXpresso, with low-level drivers using DMA provided by the developer, as well as board profiles with standard pin and clock configurations. ARM mbed compatibility, and RTOS integration are also planned for the future.

The video below introduces Atomo ecosystem, and shows a project with four LED strips.

Atomo has recently launched on Indiegogo, and the developer aims to raise at least $5,000 to fund mass production. Rewards start at $19 for the 2 IO controller board, and up to $48 for the 8 IO controller with the expansion board. The IO, power, and connector boards are not offered through Indiegogo – no wonder the campaign has not raised that much so far -,  but a 10% coupon is included with all perks to purchase them on Atomo Systems online shop.

While Atomo Systems is a one person company, but the project has “Arrow Certification” meaning this campaign has a working prototype that has been certified by Arrow Electronics, so hopefully project failure due to technical or manufacturing troubles is less likely. Shipping is free worldwide, and delivery is scheduled for June 2017.

$79 Digilent OpenScope Open Source Multi-function Programmable Instrument Works over USB and WiFi (Crowdfunding)

February 1st, 2017 8 comments

Digilent OpenScope is an open source, portable, multi-function programmable instrument used for capturing, visualizing, and controlling analog and digital signals, that works with your smartphone or computer over USB or WiFi, and it can also be used in standalone mode as a development board, like you would use an Arduino or Raspberry Pi board.

OpenScope MZ key features and specifications:

  • MCU – Microchip PIC32 MZ (MZ2048EFG124) MIPS Warrior M-class micro-controller @ up to 200 MHz with 2048KB flash, 512 KB RAM
  • External Storage – micro SD slot
  • Wireless Connectivity – WiFi module
  • USB – 1x micro USB for power and programming over FTDI
  • Programming / Debugging – micro USB port, programming header
  • Expansion – 30-pin Fly Wire connector with:
    • 2x scope channels with 12 bits @ 2 MHz bandwidth and up to 6.25MS/s sampling rate
    • 1x function generator output with 1 MHz bandwidth and up to 10MS/s update rate
    • 10x user programmable DIO pins up to 25 MHz update rate
  • Misc – 4x user LEDs, programming and reset buttons
  • Power Supply – via micro USB or ext pin; programmable power supplies up to 50 mA and +/- 4V

The platform can be used with (soon-to-be) open source, web based Waveforms Live multi-instrument software written in JavaScript and allowing you to  use OpenScope as an oscilloscope, a function generator, a logic analyzer, a power supply, or a data logger.

Since the software runs in a web browser it will work with most operating systems including Linux, Windows, Mac OS X, Android or iOS. As mentioned in the introduction, OpenScope is also a development board, and can be programmed using the Arduino IDE or Microchip MPLAB-X IDE. The company will provide  a programmer’s guide, and make PIC32MZ firmware, the agent source code, the browser app for Android & IOS, the communication protocol, and the JavaScript API available on Github

Digilent launched OpenScope on Kickstarter, where the board can be backed together with a 3D printed enclosure for $79. An “OpenScope Learning Edition” is also offered for $150 with a “parts kit with workbook example”, but no details have been provided for the latter. Delivery is planned for June or August 2017 depending on selected reward, and shipping is free to the US, but adds $20 to the rest of the world.

Satechi USB Type-C Power Meter Measures up to 65 Watts

January 29th, 2017 13 comments

CHARGER Doctor is a popular USB power meter for USB 2.0 ports that can help you check whether your charger delivers the promised amperage, and if you are dealing with USB powered device you can easily measure the power drawn by that device. But we are now in 2017, and USB type C has become more and more popular, and can deliver higher voltages higher than 5V, as well as higher currents. So if you are looking for USB type C power meter, Satechi has you covered.

Satechi USB-C power meter key features and specifications:

  • Voltage Range – 4V-20V
  • Current Range – 50mA-10W
  • Max readable Power – 65W
  • Indicates power over time (mAh) and current direction (e.g. charger to laptop, or laptop to phone).
  • USB 3.1 data pass-through supported
  • Dimensions – 6.3 x 2 x 0.8 mm
  • Weight – 8.6 g

Beside just measuring power usage, several blogs report this USB-C power meter might be able to help you detect bad cables or power adapters, as people have reported frying equipment in the past, and a USB Type-C Authentication Specification has even been announced last year to work around the issue. I’m not sure how you are supposed to do to test cables/adapters safely, as user reviews indicate the display will only turn on if you are actually charging a device.

The meter is currently for sale for $30 on Amazon US, and you may find more details on the product page.

Via Liliputing & Gizmodo

Categories: Hardware, Video Tags: power, satechi, usb