--- product_id: 71083111 title: "SainSmart 16-Channel 9-36V USB Relay Module" brand: "sainsmart" price: "$74.78" currency: USD in_stock: true reviews_count: 7 category: "Sain Smart" url: https://www.desertcart.us/products/71083111-sainsmart-16-channel-9-36v-usb-relay-module store_origin: US region: United States of America --- # Supports 9-36V DC power supply USB interface for seamless PC integration 16 SPDT relays for versatile control SainSmart 16-Channel 9-36V USB Relay Module **Brand:** sainsmart **Price:** $74.78 **Availability:** ✅ In Stock ## Summary > ⚡ Command your devices like a pro — 16 channels of power at your fingertips! ## Quick Answers - **What is this?** SainSmart 16-Channel 9-36V USB Relay Module by sainsmart - **How much does it cost?** $74.78 with free shipping - **Is it available?** Yes, in stock and ready to ship - **Where can I buy it?** [www.desertcart.us](https://www.desertcart.us/products/71083111-sainsmart-16-channel-9-36v-usb-relay-module) ## Best For - sainsmart enthusiasts ## Why This Product - Trusted sainsmart brand quality - Free international shipping included - Worldwide delivery with tracking - 15-day hassle-free returns ## Key Features - • **Visual Feedback:** Individual LED indicators for each relay ensure instant status monitoring - • **Wide Voltage Range:** Operates reliably from 9V to 36V DC to fit diverse setups - • **Power Your Automation:** Handles up to 10A/250V for robust device switching - • **Expand Your Smart Home:** Perfect for robotics, home automation, and custom electrical control - • **Plug & Play USB Control:** Easily integrate with PCs and Raspberry Pi for smart projects ## Overview The SainSmart 16-Channel 9-36V USB Relay Module is a versatile, opto-isolated relay board featuring 16 SPDT relays capable of switching up to 10A at 250V. Designed for seamless USB control, it supports a wide DC voltage range (9-36V) and includes LED indicators for each relay output, making it ideal for home automation, robotics, and custom electrical projects. ## Description SPECIFICATION Maximum load: 10A/250V Power supply: DC 9V~36V LED for each relay output Power LED USB LED WHAT'S IN THE PACKAGE 1x 16-Channel USB Relay Module Review: Mediocre, but ok for price paid. - As another has noted, do use the external power supply port and pull the jumper. It had issues just running off the usb power. I was also able to confirm the other report that sometimes if you go too fast a relay can miss a command, but I saw that more often on usb bus power. A good power supply makes it reliable and faster to respond. In my case I have hundreds of amps available. I wrote my own linux driver that waits for the reply to echo back before considering it applied. I can run this in fast process-level parallel and the reply messages can interleave. So I have a random-delay-then-retry logic to make sure it gets a correct acknowledgement. Seems to be reliable enough when I do that. See serial on then off, then parallel (don't wait for reply) on then off. That being said the rest of the world is at 115200 baud for usb serial. Why default to 9600? The ch340 family can go that fast if they changed one line of code. I also found that it's decently reliable if I close and reopen for write after every command while not waiting for a reply (about half as fast). Even though it's not perceptably any slower (at 9600 baud). That must mean the wait time before resending is clearly almost imperceptible. This means their microcontroller code is a little broken to not be handling these requests with pointer queues to a ring buffer, but they are actually doing work while they have listening turned off. I tried adding characters to pad space in time predictably. It didn't work. It's just oddly buggy when you go fast. Other then these notes, it appears to work decently enough. I'll be rewiring my van to use this to control all my 12v appliances. The LED indicator lights work well, Review: If using python convert their chart to decimal. - To control this in python, convert their spreadsheet values from hex to decimal. Excel and office libre has a built in function hex2dec. Put the corresponding row of decimal values separated by commas into a bytearray, then send to serial. Upgraded to 5 star. Been using this thing for a few years to control a semi automatic homebrew system. Once I figured out how to code for it, it was super simple to use. I like that I can control it over usb, was the big selling point. Got it connected to a raspberry pi on a touch screen. ## Features - This is USB controlled relay opto-isolated board with 16 SPDT relays. - You can use it for simple ON/OFF switching electrical devices - home lights, DC motors, solenoids and others. - It can help you building projects like robotics and home automation. ## Technical Specifications | Specification | Value | |---------------|-------| | ASIN | B0793MZH2B | | Best Sellers Rank | #513,723 in Automotive ( See Top 100 in Automotive ) #162 in Automotive Replacement Relay Control Module Relays | | Brand Name | SainSmart | | Coil Voltage | 36 Volts | | Connector Type | Usb | | Contact Current Rating | 10 Amps | | Contact Material | Silver | | Contact Type | Normally Open | | Current Rating | 10 Amps | | Customer Reviews | 3.5 3.5 out of 5 stars (42) | | Manufacturer | SainSmart | | Maximum Switching Current | 10 Amps | | Maximum Switching Voltage | 36 Volts | | Minimum Switching Voltage | 9 Volts | | Mounting Type | PCB Mount | | Operating Time | 0.5 Seconds | | Operation Mode | Electrical | | Part Number | USB Relay Module | | Wattage | 90 watts | ## Product Details - **Connector Type:** Usb - **Contact Material:** Silver - **Contact Type:** Normally Open - **Current Rating:** 10 Amps - **Mounting Type:** PCB Mount ## Images ![SainSmart 16-Channel 9-36V USB Relay Module - Image 1](https://m.media-amazon.com/images/I/71wb3DN51VL.jpg) ## Questions & Answers **Q: Where can I download the software for this board ?** A: Hi, you can download from this link: http://s3.amazonaws.com/s3.image.smart/download/101-70-208/101-70-208.zip **Q: is the ground pin of each channel connected together or each channel is totally isolated?** A: Hi, the ground of the control terminals is connected together, and each channel at the input is completely isolated. **Q: Why do the commands not work when input into a serial terminal connected to the com port assigned? using putty 9600bps 8n1 i have added \r\n** A: Not sure what you entered there and if you have a proper serial port through the USB interface. Note there are many bytes to fransfer including a checksum if I remember correctly. (Did create some Python code which uses python usb) **Q: Is it possible to expand this module to control more than 16 channels? If no, any other alternatives plz?** A: You can use a RPI with for example 4 modules, but It's better using 8-Channel USB because it contains serial number, so you have the possibility to identifiy witch module you use. It isn't possible with 2 module 16 channels on a RPI. ## Customer Reviews ### ⭐⭐⭐⭐ Mediocre, but ok for price paid. *by S***Y on August 11, 2025* As another has noted, do use the external power supply port and pull the jumper. It had issues just running off the usb power. I was also able to confirm the other report that sometimes if you go too fast a relay can miss a command, but I saw that more often on usb bus power. A good power supply makes it reliable and faster to respond. In my case I have hundreds of amps available. I wrote my own linux driver that waits for the reply to echo back before considering it applied. I can run this in fast process-level parallel and the reply messages can interleave. So I have a random-delay-then-retry logic to make sure it gets a correct acknowledgement. Seems to be reliable enough when I do that. See serial on then off, then parallel (don't wait for reply) on then off. That being said the rest of the world is at 115200 baud for usb serial. Why default to 9600? The ch340 family can go that fast if they changed one line of code. I also found that it's decently reliable if I close and reopen for write after every command while not waiting for a reply (about half as fast). Even though it's not perceptably any slower (at 9600 baud). That must mean the wait time before resending is clearly almost imperceptible. This means their microcontroller code is a little broken to not be handling these requests with pointer queues to a ring buffer, but they are actually doing work while they have listening turned off. I tried adding characters to pad space in time predictably. It didn't work. It's just oddly buggy when you go fast. Other then these notes, it appears to work decently enough. I'll be rewiring my van to use this to control all my 12v appliances. The LED indicator lights work well, ### ⭐⭐⭐⭐⭐ If using python convert their chart to decimal. *by B***N on January 2, 2019* To control this in python, convert their spreadsheet values from hex to decimal. Excel and office libre has a built in function hex2dec. Put the corresponding row of decimal values separated by commas into a bytearray, then send to serial. Upgraded to 5 star. Been using this thing for a few years to control a semi automatic homebrew system. Once I figured out how to code for it, it was super simple to use. I like that I can control it over usb, was the big selling point. Got it connected to a raspberry pi on a touch screen. ### ⭐⭐ commands missed if run too fast *by J***S on September 27, 2023* No documentation came with this, but I managed to find enough information to get it to work on the SainSmart website. I wanted to use it to control some penumatic valves. I noticed that occasionally one of my commands would be ignored, and after some testing I found that there seems to be a flaw in its firmware that will cause it to miss commands if you give the commands too fast. This device is very slow anyway, it only seems to work at a baudrate of 9600 which is much slower than other USB relays. This would have been fine for my application as I only need to switch the valves every few minutes, but the problem is I need to issue a command to close one and open another back to back, and the only way I could get it to perform reliably was to put a rather long delay after every command, which made this useless for my application. I ended up using two separate 8 channel USB relays by a completely different manufacturer. ## Frequently Bought Together - SainSmart 16-Channel 9-36V USB Relay Module - SainSmart USB Eight Channel Relay Board for Automation - 12 V - SainSmart USB 4 Channel DC 12V Relay Module Automation for Arduino Raspberry Pi DSP AVR PIC ARM --- ## 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.us/products/71083111-sainsmart-16-channel-9-36v-usb-relay-module](https://www.desertcart.us/products/71083111-sainsmart-16-channel-9-36v-usb-relay-module) --- *Product available on Desertcart United States of America* *Store origin: US* *Last updated: 2026-04-22*