Home > Hardware, Microchip PIC24 > USBminiPower USB Power Supply Delivers 3 Outputs: 5V, 3.3V, and a Variable Output up to 14.3V (Crowdfunding)

USBminiPower USB Power Supply Delivers 3 Outputs: 5V, 3.3V, and a Variable Output up to 14.3V (Crowdfunding)

Yesterday, I found out about a cheap 5V/3.3V USB power supply board, YwRobot MB-102, selling for $1 shipped on Ebay, but one person lamented the lack of 1.8V output, which may be required for example for modules like AsiaRF AWM002 that takes both 3.3V and 1.8V. One way is make your own power board, and get an expensive lab power supply, but I got a solution in my inbox this morning, with USBminiPower, as tiny USB power supply board with three output: 5V, 3.3V and a variable pin between 1V and 14.3V, as well as a 4 digit LED display showing the voltage and intensity just like Charger Doctor.

USBminiPowerUSBminiPower specifications:

  • MCU – Microchip PIC16 MCU (several are supported)
  • Voltage outputs – 5V (from USB port), controllable 3.3V, and controllable & adjustable 1V … 14.3V
  • Display – 4 Digit red LED to display intensity and voltage
  • Max Power – 2.45 Watts
  • Headers – ICSP header for uploading firmware, 3-pin for future expansion
  • Misc – Rocker switch to increase or decrease voltage for the adjustable pin. Button to enable/disable output.
  • Dimensions – 31x26mm

You just need to connect it to one of the USB port of your computer to use it. The variable pin voltage is controlled via the rocker switch. If the project is successfully funded the firmware source and hardware design files will be released. To modify the firmware yourself, you’ll need Pickit3 or ICD3 in-circuit debugger, and MPLabX installed on your computer.

USBminiPower_5VThe developer listed the project on Kickstarter where he aims to raise £5,000 or more. Rewards start at £6 (~$9) for a bare PCB, and up to £25 ($38) for a fully assembled board. Shipping is £1 to £5 extra depending on the reward and destination country, with delivery scheduled for June 2015 (Bare PCB) or August 2015 (Fully assembled PCB).

Thanks to Atanas for the tip.

  1. April 29th, 2015 at 15:26 | #1

    Can you control the voltage output in software via some libusb?

  2. April 29th, 2015 at 15:56 | #2

    @zoobab
    The developer talks about PC software to control the board, but there’s not much details. I understand he might work on it if the crowdfunding campaign is successful.

  3. Mark
    May 2nd, 2015 at 19:25 | #3

    This is interesting, but I much rather pay about another $30 to get a more conventional bench power supply, sort of like this one: http://www.amazon.com/gp/product/B0002DT0GU/ref=ox_sc_sfl_title_5?ie=UTF8&psc=1&smid=ATVPDKIKX0DER

  4. Jon Smirl
    May 2nd, 2015 at 21:11 | #4

    This costs about $3 to make. Selling for $38 is a pretty good profit.

  5. May 3rd, 2015 at 23:12 | #5

    A roll of 100x AMS1117 voltage regulators costed me 4EUR. You just need a USB connector, and you have already 5V from the USB bus, and 3.3V.

    If you need a variable voltage, you could do it with a lm317, and then control the resistor value with tiny85 maybe?

  6. May 4th, 2015 at 01:30 | #6

    For example you could control an lm317t with a PWM signal from an arduino:

    http://www.edn.com/design/analog/4363990/Control-an-LM317T-with-a-PWM-signal

  7. May 4th, 2015 at 01:33 | #7

    like here controlling an lm317t with a pwm signal from an arduino for ex:

    http://www.edn.com/design/analog/4363990/Control-an-LM317T-with-a-PWM-signal

  8. gicho
    May 4th, 2015 at 06:37 | #8

    This one uses buck/boost switch mode converter, not linear. Output voltage is controlled (programmed) by the switch (up/down). There is a microcontroller and some SW, plus indicator – $3 is just too optimistic even for BOM …
    Just try to buy some of those bubble 7 segment indicators for $3 …
    The HW itself is prepared to be controlled by the PC – the author has to implement the USB SW in the firmware to achieve this.

  9. gicho
    May 4th, 2015 at 06:40 | #9

    Also, he claims that he we publish the FW source code. So even if he is not interested in USB control, the community will make it.

  10. Jon Smirl
    May 4th, 2015 at 10:02 | #10

    7-Segment bubble is $0.50 in Shenzhen. Here’s one for $0.64 at Digikey
    http://www.digikey.com/product-detail/en/LTC-5851Y/LTC-5851Y-ND/3199012

    PIC16 is $0.80. And there are cheaper options.

    One with hardware USB support, $0.61 – EFM8UB10F8G
    http://www.digikey.com/product-detail/en/EFM8UB10F8G-B-QFN20R/EFM8UB10F8G-B-QFN20R-ND/5117112

  11. gicho
    May 5th, 2015 at 02:21 | #11

    What you’ve linked is not a bubble display, it is regular 7-segment – without optics. This project uses old “retro” indicators, made 20+ years ago by HP. What is special about them is the optics “bubble” in front of the digit that “zooms” the image. Sure there are small OLED displays that could be used. But this product uses these special displays that cost close to $3. The lite-on one is 50mm wide.

  12. Ahha
    October 29th, 2017 at 01:54 | #12

    Nice project, It would be good if it was successfully founded. But now there is a better one, called EasyVolts. It’s not only has larger output voltage range, but also GPIO, UART and RS485. And all of this can be controlled by PC over USB. More details here http://www.easyvolts.com

  13. October 29th, 2017 at 10:18 | #13

    @Ahha
    I can see there was a crowdfunding campaign but it’s over. Are you selling it somewhere, or are the design files available?

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