--- product_id: 2076922 title: "USB 4 Channel Relay Automation (5V)" brand: "sainsmart" price: "₹ 4347" currency: INR in_stock: true reviews_count: 11 category: "Sain Smart" url: https://www.desertcart.in/products/2076922-usb-4-channel-relay-automation-5v store_origin: IN region: India --- # USB 4 Channel Relay Automation (5V) **Brand:** sainsmart **Price:** ₹ 4347 **Availability:** ✅ In Stock ## Quick Answers - **What is this?** USB 4 Channel Relay Automation (5V) by sainsmart - **How much does it cost?** ₹ 4347 with free shipping - **Is it available?** Yes, in stock and ready to ship - **Where can I buy it?** [www.desertcart.in](https://www.desertcart.in/products/2076922-usb-4-channel-relay-automation-5v) ## Best For - sainsmart enthusiasts ## Why This Product - Trusted sainsmart brand quality - Free international shipping included - Worldwide delivery with tracking - 15-day hassle-free returns ## Description SainSmart USB 4 Channel Relay Automation (5V) Review: SainSmart USB 4 Channel Relay Board is pretty smart - This review is based on the experiences that I had buying/using this product. I am also going to respond to some of the other reviewers that had some "constructive" criticism had of the product. 1. First - the price and form factor are perfect. If I had to duplicate this product using other means (i.e. DAQ Board/Relay Board) -- I am going to spend $100+ for the same functionality. This product simplifies everything and its priced at less than $20. 2. Second -- the command set is simple. I know it is "interesting" when the product is not well documented (or even provided the wrong information). I was unable to get the VCP mode to work but the Bit Bang mode worked perfectly. The advantage of the Bit Bang DLL is that you can get additional information (part number, serial number). I spent roughly 4 to 6 hours working on my software subroutines which is basically a one time (up front) "cost" of figuring out a new board. 3. Finally - there were some reviewers complaining that the board does not include the capability of handle inductive kick (i.e. diodes) in the case where you are hooked up to a motor or something. In my case, I am driving some simple lights so I don't want to have the mfg include parts that I do not require or need. In summary - this is a nice product. I have bought six and used two. This product is now part of my permanent toolkit for projects. Review: Solid USB Relay - Been using this daily for 2 years now and it's a workhorse once you get it set up. Just use a Python script or a shell script to control it and it works great. LEDs doe the relays are convenient too. ## Technical Specifications | Specification | Value | |---------------|-------| | ASIN | B009A524Z0 | | Best Sellers Rank | #224,183 in Industrial & Scientific ( See Top 100 in Industrial & Scientific ) #400 in Electromechanical Relays | | Brand Name | SainSmart | | Coil Voltage | 5 Volts | | Connector Type | 5-pin Header Connector | | Contact Material | Silver | | Contact Type | Normally Open | | Customer Reviews | 3.6 3.6 out of 5 stars (43) | | Manufacturer | SainSmart | | Maximum Switching Voltage | 5 Volts | | Minimum Switching Voltage | 5 Volts | | Model | 8542140528 | | Mounting Type | PCB Mount | | Operation Mode | Automatic | | Part Number | 8542140528 | | Specification Met | Energy Rating, FCC | | Unit Count | 4.0 Count | | Wattage | 1 watts | ## Product Details - **Brand:** SainSmart - **Connector Type:** 5-pin Header Connector - **Contact Material:** Silver - **Contact Type:** Normally Open - **Mounting Type:** PCB Mount ## Images ![USB 4 Channel Relay Automation (5V) - Image 1](https://m.media-amazon.com/images/I/41KP-+1plmL.jpg) ## Customer Reviews ### ⭐⭐⭐⭐⭐ SainSmart USB 4 Channel Relay Board is pretty smart *by S***T on March 4, 2018* This review is based on the experiences that I had buying/using this product. I am also going to respond to some of the other reviewers that had some "constructive" criticism had of the product. 1. First - the price and form factor are perfect. If I had to duplicate this product using other means (i.e. DAQ Board/Relay Board) -- I am going to spend $100+ for the same functionality. This product simplifies everything and its priced at less than $20. 2. Second -- the command set is simple. I know it is "interesting" when the product is not well documented (or even provided the wrong information). I was unable to get the VCP mode to work but the Bit Bang mode worked perfectly. The advantage of the Bit Bang DLL is that you can get additional information (part number, serial number). I spent roughly 4 to 6 hours working on my software subroutines which is basically a one time (up front) "cost" of figuring out a new board. 3. Finally - there were some reviewers complaining that the board does not include the capability of handle inductive kick (i.e. diodes) in the case where you are hooked up to a motor or something. In my case, I am driving some simple lights so I don't want to have the mfg include parts that I do not require or need. In summary - this is a nice product. I have bought six and used two. This product is now part of my permanent toolkit for projects. ### ⭐⭐⭐⭐⭐ Solid USB Relay *by T***T on February 16, 2025* Been using this daily for 2 years now and it's a workhorse once you get it set up. Just use a Python script or a shell script to control it and it works great. LEDs doe the relays are convenient too. ### ⭐ Falsely-advertised - no user manual included. *by J***W on December 17, 2012* This is in response to Amazon removing my truthful feedback on a SainSmart 5V 4-CH USB relay module. Amazon said my feedback "didn't follow their guidelines". No, the problem with my feedback was that it was a truthful assessment. Amazon obviously did not perform any kind of QA/verification of this module before deciding to distribute it. And sain (the manufacturer) is selling a worthless piece of junk. BOTH Amazon AND sain are at fault. Furthermore, this item by sain is an absolute atrocity regarding quality, design, support, and operation. It's totally useless. More specifically: (1) each relay device on the module lacks a back-EMF (inductive kick) diode connected in reverse polarity across the relay coil which prevents damage to other circuitry on or connected to the module. (2) The module does NOT run on USB port power as packaged (Amazon states that it does); one must modify the module to power from the USB port. This requires installation of a jumper header (not included) and soldering. (3) sain has failed to support this module; after several email exchanges with sain regarding operation/programming of the module, they have failed to provide me with the CORRECT USB command set that controls the module. This is because they probably DON'T KNOW anything about it. In conclusion, from now on, I will NOT trust Amazon to verify quality, operation, and support of the merchandise Amazon distributes. That means, if I can't independently verify product integrity before buying, I will NOT buy from Amazon. Finally, Amazon needs to beware/screen cheap, copied-junk scams. ## Frequently Bought Together - SainSmart USB 4 Channel Relay Automation (5V) - SainSmart USB Eight Channel Relay Board for Automation - 12 V --- ## 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.in/products/2076922-usb-4-channel-relay-automation-5v](https://www.desertcart.in/products/2076922-usb-4-channel-relay-automation-5v) --- *Product available on Desertcart India* *Store origin: IN* *Last updated: 2026-05-30*