---
product_id: 32410048
title: "2pcs PCF8574 PCF8574T IO Expansion Board I/O Expander I2C Evaluation Develop Module"
brand: "hiletgo"
price: "€ 12.89"
currency: EUR
in_stock: true
reviews_count: 8
category: "Hi Letgo"
url: https://www.desertcart.sk/products/32410048-2pcs-pcf8574-pcf8574t-io-expansion-board-i-o-expander-i2c
store_origin: SK
region: Slovakia
---

# I2C interface for seamless connectivity Dual interface access: Pin or row seat 8-bit parallel I/O expansion 2pcs PCF8574 PCF8574T IO Expansion Board I/O Expander I2C Evaluation Develop Module

**Brand:** hiletgo
**Price:** € 12.89
**Availability:** ✅ In Stock

## Summary

> ⚡ Supercharge your projects with 8x I/O power — don’t get left behind!

## Quick Answers

- **What is this?** 2pcs PCF8574 PCF8574T IO Expansion Board I/O Expander I2C Evaluation Develop Module by hiletgo
- **How much does it cost?** € 12.89 with free shipping
- **Is it available?** Yes, in stock and ready to ship
- **Where can I buy it?** [www.desertcart.sk](https://www.desertcart.sk/products/32410048-2pcs-pcf8574-pcf8574t-io-expansion-board-i-o-expander-i2c)

## Best For

- hiletgo enthusiasts

## Why This Product

- Trusted hiletgo brand quality
- Free international shipping included
- Worldwide delivery with tracking
- 15-day hassle-free returns

## Key Features

- • **Expand Your MCU's Reach:** Effortlessly add 8 extra I/O pins via I2C, perfect for complex projects.
- • **Plug & Play Compatibility:** Works flawlessly with Arduino, Raspberry Pi, and other I2C-enabled boards.
- • **Flexible Interface Options:** Choose between pin headers or row seats for easy integration into any setup.
- • **Reliable & Developer-Approved:** Trusted by makers and pros alike, with proven performance in Home Assistant setups.
- • **Optimized for Smart Automation:** Ideal for controlling multiple relays or sensors with minimal GPIO usage.

## Overview

The HiLetgo PCF8574T IO Expansion Board is a compact, dual-interface I2C module that adds 8-bit parallel I/O capabilities to microcontrollers like Arduino and Raspberry Pi. Designed for projects constrained by limited GPIO pins, it supports flexible connection options and is widely used in home automation and relay control applications, delivering reliable performance and seamless integration.

## Description

desertcart.com: HiLetgo 2pcs PCF8574 PCF8574T IO Expansion Board I/O Expander I2C Evaluation Develop Module : Electronics

Review: Work OK - These work good, however they use a 1K pull-up on SDA and SCL. If you have more than one board, This is to low a value. I replaced the resistors with 10K and they work fine.
Review: Works well with Homeassistant. - Using a single GPIO pin on an esp8266 is not a limitation if a unidirectional port expander can be tolerated. I used this part to operate a 8 relay board. In this case I used an esp8266 d1mini. Here is a working YAML sketch: ------------------------------------------------------------------------------------------------------------- esphome: name: esp8266-8-relay friendly_name: Esp8266_8_relay esp8266: board: d1_mini framework: version: recommended # Enable logging logger: level: debug logs: mqtt.component: DEBUG mqtt.client: ERROR # Enable Home Assistant API #api: #encryption: #key: "q0wRAARhTmThOjrv6MpTmtEduXIIxZ9XNB5RCcWykdY=" ota: password: "a141235ccb9cb645e296e911ecfb09b7" wifi: ssid: !secret wifi_ssid password: !secret wifi_password mqtt: broker: 192.168.11.238 username: !secret mqtt_username password: !secret mqtt_password captive_portal: i2c: sda: D1 scl: D2 scan: true id: bus_a frequency: 50 pcf8574: id: pcf_expander address: 0x20 pcf8575: false switch: - platform: gpio name: "Relay 1" id: relay_01 pin: pcf8574: pcf_expander number: 0 #If the relay starts NC, add inverted: true inverted: true - platform: gpio name: "Relay 2" id: relay_02 pin: pcf8574: pcf_expander number: 1 inverted: true - platform: gpio name: "Relay 3" id: relay_03 pin: pcf8574: pcf_expander number: 2 inverted: true - platform: gpio name: "Relay 4" id: relay_04 pin: pcf8574: pcf_expander number: 3 inverted: true - platform: gpio name: "Relay 5" id: relay_5 pin: pcf8574: pcf_expander number: 4 inverted: true - platform: gpio name: "Relay 6" id: relay_6 pin: pcf8574: pcf_expander number: 5 inverted: true - platform: gpio name: "Relay 7" id: relay_7 pin: pcf8574: pcf_expander number: 6 inverted: true - platform: gpio name: "Relay 8" id: relay_8 pin: pcf8574: pcf_expander number: 7 inverted: true ________________________________________________________________________________ Remember to use the optically isolated function of the relay board for maximum safety.

## Features

- PCF8574T IO Expansion Board
- The main resources: PCF8574, I2C interface, the 8-bit parallel
- Typical applications: for I / O resource constraints the MCU I / O expansion
- Maximum Features: supports two types of Interface
- access to the target board: Pin or row seat

## Technical Specifications

| Specification | Value |
|---------------|-------|
| ASIN | B01ICN5JB6 |
| Best Sellers Rank | #1,550 in Single Board Computers (Computers & Accessories) |
| Brand | HiLetgo |
| Compatible Devices | Arduino, Raspberry Pi, and other single-board computers with I2C interfaces |
| Connectivity Technology | I2C |
| Customer Reviews | 4.0 4.0 out of 5 stars (60) |
| Manufacturer | HiLetgo |
| Mfr Part Number | 3-01-1150 |
| Model Name | 3-01-1150 |
| Model Number | 3-01-1150 |
| Operating System | Linux |
| Processor Brand | Broadcom |
| Processor Count | 1 |

## Product Details

- **Brand:** HiLetgo
- **CPU Manufacturer:** Broadcom
- **Connectivity Technology:** I2C
- **Model Name:** 3-01-1150
- **Operating System:** Linux

## Images

![2pcs PCF8574 PCF8574T IO Expansion Board I/O Expander I2C Evaluation Develop Module - Image 1](https://m.media-amazon.com/images/I/6156N3iQNQL.jpg)

## Questions & Answers

**Q: Is there a wiring schematic for the pull-up resistors to trigger a relay from a esp8266. the pcf8574 wont put out voltage to trigger?**
A: What kind of relay? Need to know voltage and current for the relay coil. Best bet is to use an fet to drive the relay.  Still need to know your relay specs to answer completely.

**Q: Are these only digital I/O or also analog?**
A: These are discrete only, no analog. 
Best to use them as active = low. I follow them with a 74LVC14A when I need active = high.
Note the chips come in 2 address ranges. I have been receiving the low range with consistency.

**Q: Leds connected with vcc = 3.3v to board make them too dim. is this usual?**
A: There are a couple of reasons this could happen. The pins on the PCF8574 can only sink 25 mA of current and, if I'm reading the datasheet correctly, can source much less. So you'll want to put the LED from Vcc to the output pin (so that low = on) and use at least a couple hundred ohms of series resistance.

**Q: Where should the pullup resistor be placed to trigger a relay from an mcu?**
A: You can use any of the I/O pins of the Device. Do not exceed rated current!

## Customer Reviews

### ⭐⭐⭐⭐⭐ Work OK
*by R***F on January 6, 2020*

These work good, however they use a 1K pull-up on SDA and SCL. If you have more than one board, This is to low a value. I replaced the resistors with 10K and they work fine.

### ⭐⭐⭐⭐ Works well with Homeassistant.
*by D***. on January 29, 2024*

Using a single GPIO pin on an esp8266 is not a limitation if a unidirectional port expander can be tolerated. I used this part to operate a 8 relay board. In this case I used an esp8266 d1mini. Here is a working YAML sketch: ------------------------------------------------------------------------------------------------------------- esphome: name: esp8266-8-relay friendly_name: Esp8266_8_relay esp8266: board: d1_mini framework: version: recommended # Enable logging logger: level: debug logs: mqtt.component: DEBUG mqtt.client: ERROR # Enable Home Assistant API #api: #encryption: #key: "q0wRAARhTmThOjrv6MpTmtEduXIIxZ9XNB5RCcWykdY=" ota: password: "a141235ccb9cb645e296e911ecfb09b7" wifi: ssid: !secret wifi_ssid password: !secret wifi_password mqtt: broker: 192.168.11.238 username: !secret mqtt_username password: !secret mqtt_password captive_portal: i2c: sda: D1 scl: D2 scan: true id: bus_a frequency: 50 pcf8574: id: pcf_expander address: 0x20 pcf8575: false switch: - platform: gpio name: "Relay 1" id: relay_01 pin: pcf8574: pcf_expander number: 0 #If the relay starts NC, add inverted: true inverted: true - platform: gpio name: "Relay 2" id: relay_02 pin: pcf8574: pcf_expander number: 1 inverted: true - platform: gpio name: "Relay 3" id: relay_03 pin: pcf8574: pcf_expander number: 2 inverted: true - platform: gpio name: "Relay 4" id: relay_04 pin: pcf8574: pcf_expander number: 3 inverted: true - platform: gpio name: "Relay 5" id: relay_5 pin: pcf8574: pcf_expander number: 4 inverted: true - platform: gpio name: "Relay 6" id: relay_6 pin: pcf8574: pcf_expander number: 5 inverted: true - platform: gpio name: "Relay 7" id: relay_7 pin: pcf8574: pcf_expander number: 6 inverted: true - platform: gpio name: "Relay 8" id: relay_8 pin: pcf8574: pcf_expander number: 7 inverted: true ________________________________________________________________________________ Remember to use the optically isolated function of the relay board for maximum safety.

### ⭐⭐⭐⭐⭐ Great I/O port
*by B***K on December 7, 2019*

GPIO pins are generally in short supply on most microcontrollers. These boards are a great way to add a couple 8-bit I/O ports to your device. Mine had a base address of 0x20, apparently some have a base address of 0x38. If in doubt code for an I2C scanner can be easily found. You could also just try 0x20 and if that doesn't work then try 0x38. These devices are easily cascadeable, one device can plug into a second (or third, or fourth...) up to a limit of eight. Of course you will have to set the address jumpers provided so each board has a unique address; if your board's base address is 0x20 you can use the jumpers to set it to 0x21, 0x22, ...0x27. One thing I did discover is that you'd be wise to add your own pullup resistors on SDA and SCL; a 4.7k resistor works well. An excellent value for the price.

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*Product available on Desertcart Slovakia*
*Store origin: SK*
*Last updated: 2026-05-18*