DC-DC Power Module
DC-DC Power Module
For any of these contraptions to work, we need to feed the ESP32 a stable 5 V. The problem is that the rig runs at 12 V, so you absolutely have to step that voltage down unless you want to let the expensive smoke out.
On this page I show you how I built a simple, working DC-DC power module that I use to power all the digital circuits in the project.
It is made up of an adjustable DC-DC converter and a few capacitors that act as stabilizers and filters, making sure the voltage is clean and steady, with no spikes to wreck your ESP32.
You can build it into each module that needs it, or keep it as a separate external supply, like I did. Cheap, easy and well worth it.
Without this, there is no S-meter, no display, no microcontroller. Game over.
Component list
DC-DC buck regulator (5-27 V → fixed 5 V)
470 µF / 25 V electrolytic capacitor
100 µF electrolytic capacitor (16 V or higher)
Filter placement summary
| Cantidad | Valor | Tipo | Voltaje mínimo | Ubicación |
|---|---|---|---|---|
| 1 | 100µF | Electrolítico | 25V | Entrada |
| 1 | 10µF | Cerámico | 16V | Entrada |
| 1 | 0.1µF (100nF) | Cerámico | 16V | Salida |
| 1 | 470µF | Electrolítico | 25V | Salida |
| 1 | 10µF | Cerámico | 16V | Salida |
Circuit
And this is what the little module looks like once assembled on the PCB protoboard.
Remember that, if you want, you can build it straight into other modules of the project, saving space and wiring.
I chose to keep it separate so I could show it in more detail, and because I like working with a more modular structure, where each part has a clear job and can be serviced or swapped out easily.
Voltage converter ready to go
As you can see, there is nothing mysterious about this module, but it is a key piece for the whole system to work.
Using a DC-DC converter with a couple of capacitors may look basic, but it saves you trouble, protects the hardware and gives you the peace of mind of knowing the ESP32 will get exactly what it needs.
Is it the most advanced circuit in the world? No. Is it useful? Very. And like everything in this project: it works, it is reproducible, and it teaches you something along the way.