Other Parts Discussed in Thread: , FDC1004, OPA690, FDC2114
Hi,
Our arm mechanical product has a problem for the avoidance function, and we need to make sure Security that the arm medanical sense the near object, for example: the human body or palm and so on;
So we choose the FDC2214 to sense the capacitance change to indentify the object distance, and then inform the MCU to move to opposite direction with the object;
Now our FDC2214 design is similar as the FDC2214EVM as below:
Our arm mechanical is the cylinder and the R=7-8cm, and we stick 4 sensor to interate the 4 direction(Up, Down, Left, Right), each sensor is the rectangle about 5*10cm(Length and width);
At first, we stick the sensor above our arm mechanical directly, and there are some noise affect sense accuray which come from the arm mechanical when it is move(the noise is more than 6000ft), we set the
sense accuray larger than 6000ft, the effective sense distance is less than 6cm;
The sencond, we add the shield layer between the arm mechanical surface and sensor, the space distance between the sensor and shield surface is about 0.5cm, it is shield the noise from the down direction,
the shield layer paramater is Gain=1 and same phase position with the sensor, and we use the amplifier is OPA690IDBVR, now we test the noise intensity, and it is distinct weakening, but the design don't very
well because the noise will come from the around of the sensor because there are 0.5cm space between the shield layer and sensor;
So our issue as below:
1. How to design the shield layer to eliminate the around noise of the sensor;
2. The amplifer is OPA690IDBVR is much more expense, so please promote the better amplifer for this design;
3. Our mimimum testing distance is 15cm, and is there are any more better reference design to solve the noise issue;
