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A project log for Windy

A connected, multi-way fan controller with synchronization and temperature logging

DaveDave 01/03/2018 at 22:170 Comments

Some initial thoughts

Here's a brain dump of the state of things, since this is the first post.

General architecture and motivation

I'm normally not one to let a particular piece of hardware (microcontroller, temperature sensor, etc.) be the driving force behind the project; it's a little backwards from a traditional engineering point of view. However, the idea for this particular project came about because of a confluence of two things:

Thus, the idea of a fully-connected, 8-way fan controller based on the ESP32 was born.  Most of the driving and speed sensing can be done right on the ESP32 itself; the PWMs and the pulse counters take care of most of the standard fan control stuff, and it can handle SD cards natively. An external temperature controller, an analog MUX and a GPIO expander can take care of the rest.

Feature set

Now that we've put the cart well in front of the horse, here's the overall feature set I'm driving towards.

All of these objectives can be accomplished with the ESP32 with a small handful of external support chips (and some discretes, in the case of the power switching/tachometer buffering).

Where I am now

I'm currently chewing through the pinouts of the ESP32 and its pre-made modules (e.g. ESP32-WROOM) to come up with the most efficient assignment matrix. Unfortunately, because of the way the ESP32 modules are pinned out (both the WROOM and the WROVER), prototypes based on the modules will have to be scaled back.  The following features are modified:

Fun challenges for the future

That's the brain dump for now.  More to come once I've actually done some more research!

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