NOYITO PC817 4-Channel Optocoupler Isolation Board Voltage Converter Adapter Module 3.6-30V Driver Photoelectric Isolated Module

I needed to interface a 12V alarm system into a component of my own design (5V). I wanted isolation and voltage conversion. This board worked fine.Some of the other reviews mentioned that grounds are connected together. This is true, and caused issues with interaction in my design. Wished that I could separate the Grounds. To solve this issue, I ordered the two channel version of the same optocoupler. In fact, I ordered a selection of the product with a selection of channels for future projects. I did find that if you use a number of these boards for I/O it can become quite a mess of wires. Nevertheless, they do a good job and I have found that they work through a wide voltage range.Great product. Recommended.

If you have a project which requires voltage level conversion or voltage isolation to reduce noise, then this board is what you need. For example, I completed a project with 12V logic inputs and outputs over a long noisy wiring run. Those 12V lines are translated though this octocoupler to switch 3V3 lines on a very sensitive microcontroler. Note: pull-up or pull-down resistors are required since this octocoupler is floating. However, the end result is a 100% reliable voltage level conversion, even when deployed in some very harsh conditions.The only limitation of this octocoupler is that the switching is too slow to translate a serial type bus, I2C, or SPI. It is really only appropriate for digital logic. Also, each channel on the octocouplter can operate at independent voltage levels, meaning that all 4 channels do not have to share the same reference voltage, such as with a transistor based logic level converter.I am extremely happy with the quality, design, and performance of this module and will make it a go to going forward.

Works fine but connectors are very finicky..the instructions could be clearer on configuration..also there is a 3 k resistor in series with the output v terminal so the actual isolated output v is going to depend on the load resistance. I used this as an emitter follower by removing the ground jumper... still not exactly clear on possible configuration and pull up pull down resistors. But works fine...leds built in is nice...

It has a small footprint, converted my 12v input signal to 5v, which is what I needed. I have a ESS smoothstepper Ethernet board for my homemade cnc machine. I ended up using 3 input pins on port #3 of my smoothstepper for 3 proximity limit swtches. My limit switches have 12v signals and my smoothstepper can only take 5.5v max input.On the input pins of the Optocoupler I connected ground and the 12v signals from my limit switches. On the output pins of the optocoupler I connected 5v to the voltage pins, and the ground pin to the smoother stepper input pins. I removed the ground jumpers on the optocoupler board. The smooth stepper has a pull down resistor on each input pin on ports #3, I think it's 47k ohms.I had issues at first because the smoothstepper port #1 has input pins too, but those input pins have 4.7k ohm pull up resistors, rather then pull down resistors. Switching to port #3 with pull down resistors fixed the issue.

It was perfect for my application

Does not work for my application as the Input grounds are tied together.I also found that Input and output grounds were tied together, but could be isolated by removing the jumper.My expectation was four totally independent couplers.The product details are incorrect. I see other similar reviews going back to 2019.Why hasn't the product information been updated ?You get what you pay for.

To start the quality control of this product is not very good. One of the two boards I ordered had one connector on backwards. This was not an issue for me, as I can solder, and I was able to reverse it. As you can see in the picture, there is a lot of play in the connectors and they don't align nicely.In regards to the design, I'm guessing someone had a specific application in mind, as opposed to a general purpose board that could be used on multiple projects. The grounding on the boards are strange, the input grounds are all tied together, and the output ground can be tied to the input grounds through a jumper. The purpose of an opto-isolator is to isolate power sources from input and output. There is little circumstances that I can think of that you'd want to share a ground between the two power systems (.e.g. no isolate them). The input output grounds are not tied together, unless jumpered to the input grounds - again most of the time you will connect to a Raspberry-PI or Arduino and you will have a common ground on the output.Before purchasing - Review the schematic and make sure this is applicable for you. It is unlikely that this board can be used directly with a Raspberry-Pi or Arduino, without some circuitry in the middle. I reworked my boards to include pull up resistors and a common ground and power bus on the output.

Works just fine. Use it to stepdown 24Volt End Limit Signals for my CNC. Down to 3.3v for the Smooth-steeper CNC Controller. Easy to mount using standoffs, and it just works. Leds are really nice to see which ports are active.