What does dps/LSB mean w.r.t. Gyroscopes?
Gyroscopes are measurement devices that provide us with angular velocity.
dps
dps stands for degrees per second. How many degrees the gyroscope rotated in one second? It is basically the dimensions for angular velocity.
LSB
In Micro-electromechanical systems (MEMS), the measurement process involves converting analog signals, obtained from the gyro sensor, to digital signals. Therefore, we inevitably have to deal with bits.
A bit is fundamentally a voltage state inside an electronic circuit which can be either high (i.e. 1) or low (i.e. 0). A byte comprises of 8 bits, all of which, of course, can either be 1 or 0. The largest decimal number that can be represented by a byte is 255, while the smallest is 0. For the sake of simplicity, we will assume that the data coming from the sensor in digital form is in bytes.
LSB stands for Least Significant Bit. The least significant bit is the right most bit in binary notation. It has the least significance since a change in its value, either from 0 to 1 or 1 to 0, does not “significantly” change the value of the represented number. In fact, of all the bits, LSB has the least effect on the magnitude of the number. On the other hand, we have the MSB, the Most Significant Bit. MSB is on the left most place, and has the most significant effect on the magnitude of the number.
dps/LSB
dps/LSB are the units used to define the sensitivity of the gyroscope. They tell us how much angular velocity will in effect change the value of the LSB from 0 to 1 or vice versa. 10 dps/LSB tells us that for an angular speed of 10 dps, we should expect to see our incoming byte as 00000001 (1 in decimal notation). For 20 dps angular speed, we should expect our incoming byte as 00000010 (2 in decimal notation). You can well guess the pattern now.
A large dps/LSB means that we will only register a change in the incoming data after a large enough difference in angular velocity. This implies low sensitivity. On the contrary, a high sensitivity, i.e. a low dps/LSB, means that we will be able to measure the angular speed after only a small increment of angular speed i.e. in greater resolution.
This article was written for the sake of noting down my learnings, and helping out someone looking for this information.
