subject: A New Generation Of Human-computer Port: Capacitive Touch Sensor Chips - Sensor Chip, Electronics - [print this page] Likely you will " Capacitance Touch sensor, "the term was unfamiliar, but if we talk like the" iPod "on the circular touch panel, LG's" Chocolate "mobile phone's touch buttons, and some appliance panels, may be immediately understood. Thank you These products enable users came into contact with these new human-machine port, which is also Semiconductor Industry demand for such microarrays, attention. In fact, the market is there such a demand. First, there is always the traditional button design gap, so there is opportunity in water, so that control panel failure, such as the word "touch sensitive" buttons on the panel, there is no gap in the integration of the panel, easy to clean. In addition, the "touch sensitive" product designer is a good news, because of the size or number of product keys is not subject to mold, button layout is completely dependent PCB The set, that is, the same mold can be due to different PCB design and layout of buttons.
Advantage "Capacitive touch sensor" is not necessarily key, can be designed as "sliders" (SlideBar) or other shapes. Such as the ATA2508 ATLAB Chip Built up to 12 programmable I / O, can be configured to match with the buttons on the light, even within the specified model Buzzer Driving population, used as a produce key tone. ATA2508 operating current of about 100mA, standby current of 60mA, sleep current of 0.1mA, power consumption is one-tenth of the other brands, but can provide a thousand times per second sampling rate, almost 25 other brands one. As the differential input, and do not need a button next to the ground, so even the water back to the button panel, nor will malfunction. Sensitivity of each key can be set individually: Set survivors is small, the more sensitive. On the contrary, the greater the set was, the more slow, inconsistent for the thickness of the shell, can be adjusted independently. ATA2508 under different radio frequency (such as the 900M ~ 2.4GHz) can work, can withstand HMBmode: 8kV, Setmode15k of ESD. There are some applications AM radio, it does not interfere with the radio. Even if the weather hot and cold, humidity level, the design can maintain the good spirit of that time-sensitive, this is because of the automatic impedance adjustment function. For different application requirements, ATALAB provided with single / double bond / all keys output mode. Working circuits with a few parts, only resistance and capacitance How many pieces can complete the work circuit.
Feel: comparison with conventional buttons, "touch sensitive keys" to face the greatest difficulties is not it, no buttons to feel, not feel. For example, when a cell phone, many people simply do not need to look at the number keys, number keys have been able to determine the location; computer keyboard is. This is because the keys used to the feeling, so this type of application is not appropriate. But other applications, there will be no touch of the question, but a lot of product engineers in the design, the key action appears, accompanied by LED Or with a buzzer that has been key. ATLABATA2508 specifically for such problems have been specially designed up to 12 I / O port (select models), and the buzzer for pin drive (select models).
Button panel material: very simple, basically as long as the non-conductive material, can be used as a "touch sensitive keys" of the shell material, but the question is printed on the panel button icons and text of the pigments, such as paint being used Some elements contain conductive material, then the button will not affect the results, such as a boot, you have to press the button.
Key with chip distance: it is best to chip in with a button to do PCB, if too far away, PCB trace is too long, will increase the chance of noise received and make the overall impedance of the keys do not match.
Old product with the touch sensitive buttons: Some of the old product is already a mature, original menu key is MCU's A / D to read resistor ladder types of keys, with touch-sensitive buttons as you want, but the Department MCU copies may not be changed, so can not directly change into. If really needed, you may want to add one MCU to implement, or use the ATA2508 provides the I / O output for key outputs.
