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

Orange Pi Development Boards

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.

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GanjaBear
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GanjaBear

> display showing intensity

Commonly known as “current” in English.

RK
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RK

Not bad at all. While my RC motor days are long behind me, I’d jump all over this if it could get around ~15w so I could replace my bench power supply.

Btw, the github repos have the C code and schematics but I couldn’t find the python script used for the GUI so I can’t be sure, but if you’re using tkinter, you can draw anything from sine waves, saws to pulses fairly easily with canvases and create_line as shown here: https://stackoverflow.com/questions/27397091/how-to-draw-sinus-wave-with-tkinter

easyvolts
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@RK
Hi RK,
unfortunately, from USB2.0 we can’t get more than 2.5W, but from USB3.0 we could get at least 7.5W in its basic configuration and maximum up to 100W in USB-C. So maybe in future, there will be more powerful EasyVolts. For UI I used wxWidgets, but at the moment it’s very buggy and dirty code, so I haven’t published it yet. It will be published as soon as there is a stable version. Re drawing on the GUI, do you suggest to make a Voltage/Current graph?

Kurting
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it is great and very handy!

easyvolts
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@Kurting
Thank you, Kurting. Hopefully, new EasyVolts with better functionality and lower price will have more success than its predecessor. I did some cost optimizations, so the price of the latest version of EasyVolts will be significantly lower (~30usd). If the interest to the EasyVolts will be large enough I’ll try to repeat crowdfunding campaign.