This gives a brief overview of the electronics roboticists should be familiar with.
A rangefinder tells you how far away something is from a sensor. A very common and cheap sensor for this is an ultrasonic rangefinder. Another variant is a laser rangefinder which is often used to determine altitude for aerial vehicles. Oftentimes these sensors utilize Time of Flight (ToF), using assumptions about the speed of sound or light and measuring how long it takes for a signal generated by the sensor to return.
A simple ultrasonic rangefinder
A laser imaging, detection, and ranging (LIDAR) sensor can be thought of as an array of laser rangefinders, often on a spinning apparatus, which provides a 2D or 3D point cloud which provides a large sampling of distances to surfaces in the environment.
A Hokuyo 2D LIDAR
You probably know what a camera is - it provides images of the environment. Most color cameras give images with 3 channels: red, green, blue. However, some cameras also provide depth - these depth cameras provide what are called RGBD images. Others can even look into other spectrums and provide thermal data.
PlayStation Eye Camera
An inertial measurement unit (IMU) is comparable to the inner ear of a human. One thing it measures is acceleration, which can be integrated for velocity and position. Integration can cause a lot of error, so it’s best not to use this as your sole source of localization. An IMU often contains a magnetometer which, like a fancy compass, can tell you heading based on the magnetic field
An early IMU about the size of a washing machine aboard the USS Midway in San Diego, California. Modern IMUs can fit in the palm of your hand.
A GPS localizes your position on Earth by triangulating its position relative to satellites. GPS, as a result, only works outdoors and does not work underwater or underground.
A uBlox GPA antenna
Intel introduced the “Next Unit of Computing” (NUC) which is its own brand of Mini PC. Many other Mini PCs have a similar form factor. They tend to be rather powerful, though occasionally somewhat power hungry as well. Most Mini PCs utilize x86 architectures, which are ubiquitous in most PCs (except for the M-series Macs).
An Intel NUC
A single board computer is a smaller computer often designed to be embedded in a system. They tend to be lower cost, with lower computing power and lower power consumption. They also generally feature General Purpose Input Output (GPIO) pins to interface with hardware. Many feature ARM architecture chips, so the compatibility of software with this architecture is an important consideration.
A Raspberry Pi 3 in a case
The Nvidia Jetson series of computers resemble SBCs but with the addition of Nvidia GPU computing cores. These make these computers very useful for machine learning algorithms which are accelerated by parallel computation.