Juntek,Drok programmable buck converters NT.

Juntek and Drok sell some interesting cheap programmable buck converter modules e.g.: DPS3806 Buck3603 Drok low Power Drok high power

They are all controlled by a pluggable module, which stages a STM microcontroller and a 4x7 digit LED display. The 4 push-buttons to control the operations are clumsy and the seven segment display is everything but comfortable. The Drok modules provide a serial port to control the operation, the Juntek do not.

Both are however running according to the same principle: On the left side the connector gets two PWM voltage and current control inputs and deliver two voltage and current control outputs all in the range 0..2,4V.

My idea was to get rid of the original control module, and to replace it by an ESP32 WiFi enabled microcontroller. I used a Wemos ESP32 with an integrated 128*64 OLED display plugged onto a 6*8cm prototyping board as an adapter.


OK it was not straight forward to get the crappy ADCs of the ESP32 to work correctly, but I now got it running.

Now the fun can begin. Recycling a big part of the software resources of MPPT Soft Power I will be able to provide much more than just a simple programmable power supply.

The power supply is (will be) controllable by: a) USB -Serial with a simple menu to change the set-points control the OLED display variants and print reports b) from everywhere in the world using the cloud dashboard service thinger.io with a free limited maker account. |498x500 this is just an example, much more will come. c) a IR remote control. d) remote screen replication

Over the serial port many reports will be made available: -energy report by the second, the minute, the hour. -Ah, Wh Joule/Coulomb reports by the minutes, the hour, the day.

Beside the usual constant voltage and constant current set points, I will provide many interesting things that are not common, but very useful:

The power supply will provide:

Battery Charger mode: - charging profiles for many battery chemistries, - evaluation of the battery internal resistance - evaluation of the battery capacity - charging plots

Power Source emulation: - programmable internal resistance - constant power mode - solar panel / wind turbine simulation

Programmable Load (for the Juntek buck.-boost version - together with a flooder to dissipate the energy the buck-boost converter can be used to discharge batteries and transfer energy from one battery to another one.

Maybe other useful ideas that you might have...

Last but not least everything is neatly self powered, and integrated, on one single board, that plugs instead of the original controller board, which you could use as well, if you wanted to revert to the original functionality. There is absolutely no cable mess and even a new program can be updated over the air. You need no additional computer to manage the dashboards, everything is done in the cloud. The only thing you need, is a Wifi connection.

Looks like a lot of work and fun! Is this a future project to be shared?