--- product_id: 184985312 title: "Comimark 3Pcs PCF8574 PCF8574T I2C 8 Bit IO GPIO Expander Module for Arduino & Raspberry Pi" brand: "comimark" price: "£8.34" currency: GBP in_stock: true reviews_count: 3 url: https://www.desertcart.co.uk/products/184985312-comimark-3pcs-pcf8574-pcf8574t-i2c-8-bit-io-gpio-expander store_origin: GB region: United Kingdom --- # 3 Pack I2C Interface 8 Bit IO Comimark 3Pcs PCF8574 PCF8574T I2C 8 Bit IO GPIO Expander Module for Arduino & Raspberry Pi **Brand:** comimark **Price:** £8.34 **Availability:** ✅ In Stock ## Summary > 🚀 Expand Your Tech Universe! ## Quick Answers - **What is this?** Comimark 3Pcs PCF8574 PCF8574T I2C 8 Bit IO GPIO Expander Module for Arduino & Raspberry Pi by comimark - **How much does it cost?** £8.34 with free shipping - **Is it available?** Yes, in stock and ready to ship - **Where can I buy it?** [www.desertcart.co.uk](https://www.desertcart.co.uk/products/184985312-comimark-3pcs-pcf8574-pcf8574t-i2c-8-bit-io-gpio-expander) ## Best For - comimark enthusiasts ## Why This Product - Trusted comimark brand quality - Free international shipping included - Worldwide delivery with tracking - 15-day hassle-free returns ## Key Features - • **Perfect for Makers:** Ideal for hobbyists and professionals alike, this set of 3 ensures you have enough to tackle multiple projects. - • **Expand Your Horizons:** Unlock the full potential of your Arduino and Raspberry Pi projects with this versatile GPIO expander. - • **Seamless Integration:** Effortlessly connects via I2C, making it a breeze to enhance your device's capabilities. - • **Compact & Lightweight:** Weighing only 0.634 ounces, this module is designed for portability without compromising performance. - • **Future-Proof Your Tech:** Stay ahead of the curve with a product that enhances your tech toolkit and keeps you connected. ## Overview The Comimark 3Pcs PCF8574 PCF8574T I2C 8 Bit IO GPIO Expander Module is a must-have for tech enthusiasts. Compatible with both Arduino and Raspberry Pi, this set of three modules allows for seamless GPIO expansion through a user-friendly I2C interface. Lightweight and compact, it's perfect for a variety of projects, ensuring you can innovate without limits. ## Description Comimark 3Pcs PCF8574 PCF8574T I2C 8 Bit IO GPIO Expander Module for Arduino & Raspberry Pi ## Features - Compatible with Arduino and Raspberry Pi. - 8 Bit IO GPIO expander. - Utilizes I2C interface. - Comes in a set of 3 pieces. - Facilitates expanding GPIO functionality. ## Technical Specifications | Specification | Value | |---------------|-------| | Brand | Comimark | | Item model number | LY438 | | Item Weight | 0.634 ounces | | Package Dimensions | 5.75 x 3.78 x 0.94 inches | | Processor Brand | Broadcom | | Number of Processors | 1 | | Manufacturer | Comimark | | ASIN | B07X3KWQZ7 | | Date First Available | August 26, 2019 | ## Product Details - **Brand:** Comimark - **Connectivity Technology:** I2C - **Included Components:** Comimark 3Pcs PCF8574 PCF8574T I2C 8 Bit IO GPIO Expander Module for Arduino & Raspberry Pi - **CPU Manufacturer:** Broadcom - **Compatible Devices:** Arduino, Raspberry Pi ## Images ![Comimark 3Pcs PCF8574 PCF8574T I2C 8 Bit IO GPIO Expander Module for Arduino & Raspberry Pi - Image 1](https://m.media-amazon.com/images/I/61kEAxm7rGL.jpg) ## Customer Reviews ### ⭐⭐⭐⭐⭐ Work fine! *by J***M on March 3, 2021* These expanders work perfectly once you figured out the address. On Arduino, the address is 0x20 by default not as 0x40 as documented by the some datasheets. This is because the datasheet counts the R/W bit as the first bit and Arduino does not count this bit and thus the address is divided by 2. Thus if you change the jumper on A0 to VCC, the address is 0x21 in Arduino and not 0x42 like in the datasheets. ### ⭐⭐⭐ These chips cannot source much current. Consider alternatives. *by D***D on October 10, 2023* I didn't do my research so shame on me. Warning to others to avoid wasting time/money if this doesn't work for your needs like me.I give it 3 stars because it might work for a limited solution. You probably can use this for detecting a switch pulling a pin low but that is about as useful as this gets. Maybe an ok input expander. HOWEVER; if you want to use it as an output expander to do anything like drive a SS relay or something that needs any kind of current forget it. This will NOT work. Tried many different pull-up resistor arrangements and just could not get a 3.3v (ESP32 based setup) to work with any of my SS relays. I don't know if it would work better in a 5v setup but in my situation I'd have to add additional transistor circuitry to drive any kind of SS relay. Not what I wanted to do with better solutions available. Fair warning to anyone considering this.Search for details on the 8574 chip and you'll see. IMO something like a MCP23017 based module is a much more versatile solution. That's what I ended up using. ### ⭐⭐⭐⭐⭐ Excellent port expander *by P***R on November 27, 2020* Bought 6, tried 3 so far, all worked perfectly. They appear on I2c starting at address 0x20 and on Arduino each one requires a separate declaration. These are very handy when you need a bunch of associated inputs: I needed 24 to read a hall effect sensor array for a wind vane sensor.The 3144 hall effect sensors are open collector but I did not use pull up resistors while prototyping though I was prepared to. They have no problem registering hi/lo inputs, at least well enough for my purposes. I’m polling three of these every 15ms and as I run the pin of a grounded Dupont wire down the length of these input pins I get clean, one at a time state transitions on each pin in sequence. Don’t ground the interrupt pin, odd things happen. It may be used to clock data out when you use it as an output port - I didn’t check.The interrupt pin is open collector so you could tie several together to interrupt the processor, except the interrupt appears to stay active as long as the input stays active: if a second input goes active that event can’t generate another interrupt. Normally the interrupt would clear when the register is read but I didn’t see that. ## Frequently Bought Together - Comimark 3Pcs PCF8574 PCF8574T I2C 8 Bit IO GPIO Expander Module for Arduino & Raspberry Pi - ELEGOO 120pcs Multicolored Dupont Wire 40pin Male to Female, 40pin Male to Male, 40pin Female to Female Breadboard Jumper Ribbon Cables Kit Compatible with Arduino Projects - NEXTION 16 Keys Matrix Keypad 4x4 Membrane Keyboard Module Array Switch for Arduino --- ## Why Shop on Desertcart? - 🛒 **Trusted by 1.3+ Million Shoppers** — Serving international shoppers since 2016 - 🌍 **Shop Globally** — Access 737+ million products across 21 categories - 💰 **No Hidden Fees** — All customs, duties, and taxes included in the price - 🔄 **15-Day Free Returns** — Hassle-free returns (30 days for PRO members) - 🔒 **Secure Payments** — Trusted payment options with buyer protection - ⭐ **TrustPilot Rated 4.5/5** — Based on 8,000+ happy customer reviews **Shop now:** [https://www.desertcart.co.uk/products/184985312-comimark-3pcs-pcf8574-pcf8574t-i2c-8-bit-io-gpio-expander](https://www.desertcart.co.uk/products/184985312-comimark-3pcs-pcf8574-pcf8574t-i2c-8-bit-io-gpio-expander) --- *Product available on Desertcart United Kingdom* *Store origin: GB* *Last updated: 2026-05-21*