September 2012

Doc ID 023229 Rev 1

1/17

UM1546

User manual

STEVAL-IHM037V1 remote fan speed controller

Introduction

The remote fan speed controller is a single channel TRIAC based solution meant to replace

the existing fan speed controllers and provide the IR remote control feature. It is designed to

fit easily inside an enclosure with the dimensions of a single-switch module.

A non-isolated capacitive power supply is used to power the microcontroller and the IR

sensor. The TSOP38438 IR sensor is used to demodulate the 38 kHz IR signal from the IR

transmitter and decoded by the STM8S003 value line microcontroller to perform the various

control functions. IR communication is based on the RC5 protocol standard. A TRIAC is

used as the control element to regulate the power going into the fan by varying its firing

angle for different speed settings. The speed settings can be changed by using the onboard

tactile switches or by using the IR remote controller.

The STM8S003F3 value line 8-bit microcontroller, with its internal data EEPROM, hardware

timers and external interrupts on GPIOs, makes an efficient implementation of the

application possible while keeping the size, cost and external component count to a

minimum.

Figure 1.

Remote fan speed controller board STEVAL-IHM037V1

This document explains the different parts of the application.

The key features of the application are:

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