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Posts Tagged ‘power’

$17 Sonoff S31 Wireless Smart Socket Includes Energy Monitoring Function

December 27th, 2017 10 comments

ITEAD Studio has just launched another Sonoff Smart Home product with Sonoff S31 WiFi smart socket with energy monitoring. Just like Sonoff switches, light bulbs, and their other products, the device can be controlled using eWelink app for Android or iOS, and supports integration with Amazon Alexa, and Google Assistant.

It should be noted that the company only provide a US plug version for now, and so far, there’s no Wiki link, so while it’s likely based on ESP8266 or ESP8285 like their other Sonoff devices, it may not be designed to be easily hackable, although I suspect the electronics may be similar to Sonoff POW switch (TBC).

Sonoff S31 hardware specifications listed by ITEAD:

  • Voltage Input – 90~264V AC, 50/60HZ
  • Max. Current – 16A
  • Max. Power – 4200W (Note package above reads max load: 220V/10A)
  • Gang – 1x US type with ground
  • Connectivity – 802.11 b/g/n WiFi with support for WEP/WPA-PSK/WPA2-PSK
  • Misc – Power button, LEDs
  • Dimensions – 75.7×39.7x32mm
  • Weight – 135g
  • Temperature Range – -20 °C ~ 75 °C
  • Humidity – 10%-80%

The socket also includes overload protection for safety, and once you can install eWelink app for Android/iOS to control it remotely, monitor power consumption, and estimated electricity bill, set timers, and securely share with other users in the home.

The company also highlights the compact design, claiming users will be able to connect two sockets on their 2-gang boxes. If you prefer alternative open source firmware like Sonoff-Tasmota or ESPurna, you’d have to wait or do it yourself since the product is still very new.

Many people on Facebook complain about the lack of EU plug, so hopefully the company will take note and soon offer a compatible version, but in the meantime you can purchase the US version of Sonoff S31 for $16.90 plus shipping on ITEAD Studio store. [Update: Sonoff S31 can also be found for $16.90 shipped on Aliexpress]

EasyVolts USB Dongle Outputs 0-24V DC, Exposes UART, GPIO/PWM, RS-485 Signals

November 6th, 2017 5 comments

A while ago, I wrote about USBminiPower, a USB power supply with 3.3V, 5V, and one variable DC output up to 14.3V adjustable with a rocker switch, and equipped for a 4-digit LED display showing current intensity and voltage.

But recently, I was made aware of another USB power supply – EasyVolts USB dongle – that supports 0 to 24V DC, and also exposes either UART pins, or RS-485 signal, plus two GPIO/PWM pins.

EasyVolts specifications:

  • USB – 1x USB port for power, communication
  • Power Supply function:
    • Input voltage: 5V from USB port
    • Output voltage: 0-24V
    • Max output current: 1A
    • Max output power: ~2.4W (e.g. 24V/0.1A; 3.3V/0.55A)
    • Voltage resolution: <50mV
    • Current resolution: <2mA
  • I/O expansion
    • 4- pin to be used as UART (Tx/Rx) or RS-485 + 2x GPIO/PWM
    • UART – speed: 300-230400 bit/sec; resistance of Tx/Rx pins: 300 Ohm
    • PWM – Base frequency: 240kHz.; frequency division configuration: 1-65535; duty cycle resolution: 0.5%.
    • Logic levels – 3.3V

When the device is connected to USB it appears on PC as two virtual COM ports. One is used to control power supply and GPIO, the second – as “USB-UART/RS485” adapter. This allows you to control the device easily with any software that can communicate over COM port, but to make things easier, the developer – Valerii Proskurin – also wrote EasyVoltGUI program, showcased in the video below to control a servo using PWM signals.

A 0-15V version of EasyVolts (Rev. 1) was first launched on Indiegogo a few months, and I did not exactly work according to plans, as the project did not get funded. But the developer has now released the hardware design files (DipTrace’s schematics & PCB layout, BoM and Gerber) for the first revision of the board, as well as the firmware source code on Github.

The new revision of the board with 0 to 24V support is not available yet, but you can follow progress on EasyVolts website and blog.

Categories: Hardware, Microchip PIC24, Video Tags: power, usb

ESPurna Firmware Now Supports Power Meters “Augmented” with ESP8266 Modules/Boards

September 25th, 2017 15 comments

Sonoff-Tasmota and ESPurna are the two main open source firmware used in home automation devices, such as Sonoff wireless switches, based on Espressif ESP8266 WiSoC. Xose Pérez – aka Tinkerman – has recently purchased “dumb” power meters / kill-a-watt meters, added WiFi to them with ESP-01 module and Wemos D1 mini board, and implemented support in ESPurna firmware leveraging earlier reverse-engineering work by Karl Hagström.

The power meter above looks exactly like the one I’ve been using for review for over two years, and has been more more reliable than other models, such as Broadlink SP2 (with built-in WiFi) that gave up on me after a few months.

Xose actually noticed that old and newer models of the power meters were based on different solutions. Karl’s meter relied on ECH1560, while Xose’s new meter was instead based on Vango V9261F, which has a public datasheet, and was already being worked on by Domoticz community.

While he connect ESP-01 to one of the meter, he found Wemos D1 mini was much easier to connect thanks to a built-in 5V support. He still had to include a Hilink AC to 5V DC power supply module, a baseboard for the Wemos board with an optocoupler and resistor. Finally (not shown in pictures), he hot-glued all cabling to make sure nothing move, and that’s important as you don’t want anything bad happens with AC voltages…

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The power meter can then be calibrated and configure in ESPurna user interface, and you can also handle the data through MQTT, Domoticz, a REST API, and/or Home Assistant. Support for V9261F has been implemented and tested, but while the older ECH1560 solutions have been implemented, they have yet to be tested.

The power meter can be purchased for about $12 and up on eBay or Aliexpress, ESPurna firmware on BitBucket.

USBCEE Tiny-PAT Board Helps Testing USB-C Power Adapters (Crowdfunding)

September 13th, 2017 No comments

USB power delivery allows for up to 100W charging using 20V @ 5A through a USB type C port, and the specifications also mandate supports for various voltages between 5V and 20V. However, some USB-C power adapter that not be fully compliant with the specifications, potentially risking to damage your device. USBCEE Tiny-PAT board has been created in order to test such power adapters to make sure they are compliant with USB PD 2.0/3.0 specifications.

Tiny-PAT board features and specifications:

  • Supported USB Spec Version – PD 2.0 / PD 3.0
  • Max Voltage: 24 V
  • Max Current: 5 A
  • Max Power: 100 W
  • USB type C receptacle
  • Misc – Fail and Pass LEDS, S4 mode button, through holes for VBUS & GND
  • Power Consumption: ~10 mA (may vary based on voltage)
  • Dimensions – 35 x 20 mm

By default, the board will test all power rules advertised by the power adapter, measure the voltage (VBUS), and show whether the test failed or passed with the LEDs on the board.

USB PD 3.0 Power Ratings, Voltages and Currents – Source: Texas Instruments

S4 button is used to switch to manual mode, where you can switch between each power rule, and verify the voltage(s) with a multimeter, external load, or oscilloscope. In that mode, Tiny-PAT could also be used a variable power supply where you can for example, select 5 V/3 A, 9 V/3 A, 15 V/3 A or 20 V/4.35 A  with Apple’s 87 W USB-C power adapter, or 5 V/3 A, 7 V/3 A, 8 V/3 A, 9 V/2.7 A, or 12 V/2 A with Verizon USB charger. The company promises to release schematics under an open license.

USBCEE has launched a CrowdSupply campaign to raise some funds for mass production of the board. A pledge of $40 should get you a Tiny-PAT board shipped at the end of November. Shipping is free to the US, and adds $7 to the rest of the world.

Categories: Hardware, Video Tags: crowdsupply, power, qa, usb

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 6 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 15 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.