4x4 Keypad 16 Key 4PCS Matrix Array Membrane Switch Keypad Keyboard for Microcontroller

Based upon some of the other reviews, I decided to test all 4 keypads right away. Since the keypads did not provide ANY documentation, I went online and found the standard connections for a keypad. The new keypads exactly matched the standard connections and all of the keys on all of the keypads worked flawlessly. I agree with one of the other reviewers that a wiring diagram would have been nice.

well made key pads. Just wish they would include a schematic somewhere. I had to find a diagram on the internet which ended up being opposite of the keypads I bought. Was easy to change the pins. I'd definitely buy again.

I did not expect the contact resistance to be so high ~50 ohms. That said, the application I was investigating should not care. The connectors are a little flakey so I would advise seeing how uniform the contact resistance is across the switches.

Went through two of these in an afternoon. Entire rows or columns would stop working after a while. Do not recommend these at all. I knew they were cheap, but not expecting failures after a few clicks. I'm going to have to find new keyboards for my project.

Seem to be good quality, but I’m have yet to actually get them to work… maybe someday

It helped me to prove of concept of a project. Not difficult to program.

This product is exactly what I needed!

I wanted to try building an escape room in a box for fun so I needed a few of these. Luckily 3 of the 4 work so I'll have enough, but I wish I had only paid 3/4 of the money. Documentation would have been nice as they do seem to be opposite of what I had found on other sites.