{"id":22450,"date":"2025-01-28T18:38:59","date_gmt":"2025-01-28T18:38:59","guid":{"rendered":"https:\/\/liquidinstruments.com\/?p=22450"},"modified":"2025-04-18T23:30:05","modified_gmt":"2025-04-18T23:30:05","slug":"analyzing-time-of-flight-data-from-a-lidar-distance-sensor","status":"publish","type":"post","link":"https:\/\/liquidinstruments.com\/white-papers\/analyzing-time-of-flight-data-from-a-lidar-distance-sensor\/","title":{"rendered":"Analyzing time-of-flight data from a LiDAR distance sensor","gt_translate_keys":[{"key":"rendered","format":"text"}]},"content":{"rendered":"

One method for determining the distance to an unknown object involves reflecting pulses of light off the object and detecting the reflection. The time difference between the transmitted and received pulses is then calculated and multiplied by the speed of light, giving the total distance that the light traveled back and forth from the object. This method, called a time-of-flight measurement, is often used in radar and LiDAR applications.\u00a0<\/span><\/p>\n

In this application note, we use <\/span>Moku:Go<\/span><\/a>, an FPGA-based device from Liquid Instruments that offers a reconfigurable suite of test and measurement instruments, in conjunction with a commercial range finder to perform precise time-of-flight measurements. The range finder will emit and detect infrared pulses and provide a stream of serial data to the Moku:Go device. Moku:Go also serves as the power source and the decoder for the serial data provided by the range sensor. We will demonstrate how to visualize this serial data using both the Moku <\/span>Oscilloscope<\/span><\/a> and <\/span>Logic Analyzer \/ Pattern Generator<\/span><\/a> instruments. Finally, we will automate the measurement using the <\/span>Moku Python API<\/span><\/a>.\u00a0\u00a0<\/span><\/p>\n

Required materials<\/span><\/h2>\n

To perform this experiment, you will need the equipment listed below. See Figure 1 for a visual guide.<\/span><\/p>\n

Moku:Go: <\/b>This setup specifically calls for a Moku:Go<\/a> device because it offers a built-in programmable power supply. Here, we use it to power the LiDAR distance sensor. If you have different Moku hardware, then you will also need a 5V DC power supply.\u00a0<\/span><\/p>\n

Two banana-plug-to-alligator-clip wires: <\/b>These will connect to the Moku:Go and provide 5 V of DC power to the range finder.\u00a0<\/span><\/p>\n

One BNC-to-alligator clip wire: <\/b>This will be used for passing the serial data from the range finder to the input of the Moku:Go.<\/span><\/p>\n

LiDAR distance sensor: <\/b>The range finder that we are using for this experiment is the <\/span>TF Luna<\/span><\/a> from Benewake. The TF Luna measures distance by calculating the time-of-flight of a pulse train of infrared light. This data is then sent to the receiver via UART serial encoding<\/a>. A link to the documentation for this device is available in the References section at the end of the article. The TF Luna has six connecting wires; here, we use only the power, ground, and Tx wires. These connections are labeled in Figure 1.\u00a0<\/span><\/p>\n

\"Equipment<\/p>\n

Figure 1: Equipment required for the time-of-flight demo. Left: TF Luna<\/a>, with the three connections labeled. Center: BNC-to-alligator connection wire. Right: Banana plug-to-alligator clip connection wires.<\/p>\n

Setting up the equipment<\/span><\/h2>\n

These steps outline all of the connections to be made between the instruments. The full schematic is shown in Figure 2.\u00a0<\/span><\/b><\/p>\n