Problems with the KY series kits (a.k.a 37 in 1 Sensor Kit)

The KY series kit is a kit that contains 37 different sensors and is typically the bootleg version of the original (and more reliable) Keyes series kit. The value of this kit is that makers can try out many different projects with the wide variety of sensors. Companies selling these kits can be very convincing in making buyers think that the kit is worth buying by driving down its price to a fraction of what a Keyes kit would cost. Wow, 37 sensors in 1 kit for such a low price? Sounds too good to be true? Yes, and we’re calling them out on their nonsense. The KY series kit is definitely not as maker-friendly as what the companies marketing them make it out to be.

Here's what our engineering team discovered after painstakingly testing through all 37 modules for the whole of last week.

What's actually good

First, we have to commend the kit for including some useful sensors, such as the temperature and magnetic field sensors. Many of the modules also came with a useful on-board LED and resistors already connected to the main component. This makes it easy for the modules to be wired up for a project since the 2.54mm pitch spacing of the male header pins on the modules makes them breadboard-friendly.

With that said, let's look at some of the problems plaguing the modules in the KY series kit.

Mislabeled Pins & Modules

Almost all the modules had mislabeled pins on them. This makes for a frustrating process for a beginner to use the modules. It’s difficult enough to troubleshoot a project when you’re not even sure what’s wrong in the first place. Add mislabeled pins into the mix and no amount of tech forum can help the discouraged beginner maker. Here at MakerSupplies, we try to be as beginner-friendly as possible, so we tested them all and wrote the correct pin configurations in our listing details.

Wrong pin label on RGB LED
Unless our entire team is color blind, that is not red 🙄
7 Color LED labelled DHT11
Last we remember the DHT11 Temperature and Humidity Sensor did not come in the form of an LED


Prohibited & Dangerous Items

The kit also contains potentially dangerous items such as mercury switches and lasers. These items were not properly labelled and because of that, can potentially bring harm to younger makers who may not be aware of the potential danger. Typically, the sale of items containing lasers and mercury would be heavily regulated in most countries, so we’re not sure how these kits are even being sold to so many countries so easily.  

Mercury Tilt Switch and Laser Module
Products that contain mercury or lasers are controlled imported goods in Singapore

Heart Rate Sensor Module 

This one’s a heart breaker. There's a module in the kit labelled as a Heart Rate Sensor and if you are like us and got very excited thinking about all the heart rate tracking devices you can make with this module, prepare to be very disappointed. 

The module only works if you put your finger between the IR LED and the IR Receiver. The receiver then reads the fluctuating signals of IR light as it passes through your finger. While this is how commercial finger heart rate sensors work, IR light isolation and complicated algorithms are required to obtain an accurate reading. Some have managed to make it work with fairly complicated algorithms but the truth is that the module is not as user-friendly  as the creators made it out to be.


Due to all the above-mentioned reasons, we found that out of the 37 items in the kit, less than 20 were usable and can be legally sold in Singapore. As such, we are dismantling the kit and selling the modules individually. Do note that all the modules sold have been tested to be functional, despite having mislabeled pins. Hence, we have written the proper labels in the description section of the respective items. We will sell these modules while stocks lasts.

Got problems with your 37-in-1 sensor kit too? Or have a question on any of the modules? Leave us a comment down below!

Ky series

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