what should we note when we design sensors

As we know,a sensor is a device that converts real world data (Analog) into data that a computer can understand using ADC (Analog to Digital converter).its functions depend on its design.Then what should we note when we design sensors?

1, How to get the useful signal as much as possible and try our best to reduce the noise.That is the primary problem that we should solve .

In general,The data we measure is very small.At the same time ,It always with  converting noise from the sensor. For example, the  signal strength is 0.1 ~ 1uV when  the sensor  in twice natural size,and  this time the background noise signal has such a large level, even annihilation.

2, the sensor circuit must be simple refining.

Let‘s guess,here is a 3-stage amplifier circuit with a 2-stage active filter amplifies .when we amplify the signals ,the noise would also be amplified. If the noise does not significantly deviate from the signal spectrum,no matter how we amplify the filters at the same time, SNR(Signal to noise ratio) did not improve. Therefore, the sensor circuit must be refined simplicity. We should strip out resistors or capacitors as much as possible ,which is easily overlooked in the design of  sensors. The known situation is that the sensor circuit with the problem of noise problems, the more complex, the more modified circuit.it’s a vicious circle.

3, power consumption.

The sensor is usually in the front of the subsequent circuit ,needed longer lead to connect. In large-power sensors,the lead wires will take unnecessary noise and power supply noise, which would cause the subsequent circuit are more difficult to design.How to  reduce power consumption with enough length is also a challenge.

4, the selection of components and power supply circuit.

The Power supply is always a major challenge in  design process .we need to remember is that,do not pursue the power indicators which can not be achieved, and choose a good common mode rejection ratio of the op amp.Power decoupling must be a reliable design,  following the requirements of the device manual.

 Author ：Ferdinand Rinol— WIN SOURCE ELECTRONICS