Product Design: electronics STEM kits for kids between age 6 to 15

Want to develop an electronics STEM kits for kids between age 6 to 15. Following things should be kept in mind while designing/developing the product. • Should be an electronics kit simple to assemble. • Should be a plug and play type. Like interlocking, building block type. • No microcontroller based • Basic components like, LED, buzzer, ultrasonic, dc motor, photoresistor etc should be used. • You can use our own innovation and let us know. • PCB layout, schematic, BOM , Gerber, .pcbdoc files should be given. • You can refer the below type of products for reference. You can use them for reference purpose but need to add or enhance from it so that it should be a complete package. The links given for reference purpose to get an idea of what kind of product we are looking for. [login to view URL] [login to view URL] [login to view URL]