Principle The touch key is divided into upper and lower layers, the upper layer is the main circuit and interface part of the key, and the lower layer is the magnet fixing base. The whole machine uses chip to sense the capacitance change from the metal ball. After the human body touches the metal ball, the capacitance change is transmitted to the relevant pins of the chip through , and the relevant keying signal is amplified and by the triode, and finally transmitted to the At the key interface, the logic of the whole machine is that the effective keying signal is low level, and the non-touch signal is 5V high level. This level form matches the operation of most radios. The lower layer is a strong magnet, which can be sucked on any iron shell and play the role of fixing the electric key. Instructions for use: The USB cable can be connected to a mobile phone charger or a computer. Note that the USB must be powered by 5V, and other voltages will burn the chip. After the power is turned on, the LED at the position of the USB port will , indicating that the power supply is normal. At this time, if you touch the left and right metal balls, you can see the LED light at the corresponding ball position. At this time, the touch is valid and the product function is normal. The touch button on the right is for a short time, which represents a point, and the touch button on the left is for a long time, which represents a stroke. Features: The key is made with product, The user can realize all the functions of automatic CW by touching the ball with two This product's metal balls and most bolts are made of 304 stainless steel Simple and convenient to use Applicable to Maker Group Product parameters: Power supply voltage: Type-c interface DC-5V Output erface: 3.5mm interface Operating environment: -40C to 85C Color: As Shown Material: metalandplastic Package Contents: 1 x Touch key Only the above package content, other products are not included. Note: Light reflection and different displays may cause the color of the item in the picture a little different from the real thing. The measurement allowed error is 1-3cm.