Questions tagged [distance]

190 questions
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How do lasers measure short distances (<1cm) when electronics are too slow for time-of-flight to work?

I was wondering how LIDAR sensors are able to measure distances less than 2mm. I don't see how they can possibly do that. The speed of light is 300,000,000 m/s, so the round-trip time should be within 14ps which is far beyond the capabilities of…
Ron Vaisman
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Any published designs for time-of-flight laser distance measurement

Does anyone have any references/examples for detailed circuitry for time-of-flight laser distance measurements - schematics, appnotes etc.?
mikeselectricstuff
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Can an optical mouse be used to measure distance down to 1-10μm?

I am working on a home-built CNC machine that uses stepper motors and MXL timing belt for the machine movement. Because I'm using steppers, there is no feedback to the controller about the actual position of the machine (ie, open-loop). Sometimes…
dext0rb
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Options for short range distance determination between two objects

I have a project idea in mind, but it involves calculating the distance between two people. I've looked into Bluetooth, RFID, and NFC (unsure about this one), but none appear to offer the accuracy I would need (I am a novice at best, so I would…
Ryan
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What are my options for detecting the position of a small moving metal object?

This is an airgun pellet trap: I fire small metal pellets at it (4.5mm = .177" in diameter) at up to 120 m/s = 390 fps. What are my options for detecting the X / Y position at which it enters the target? Does it make it easier if I only need to…
Tobia
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Ideas to measure 2D position of an object constrained to X-Y plane

I am working on a project, and an aspect has come up where I would like to measure (track continuously) the X and Y position of an object across a 2D plane. The object is moved by a person, with the object's movement constrained to the 2D plane (so…
boardbite
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How do I implement accurate distance measuring (to ground) on a plane-like UAV for heights over 10m?

How do I implement drone-to-ground distance-measuring for autopilot landings for heights over 10m? I found ultrasonic to be too inacurate, let alone GPS. Maximum height is 1000m, Vmax is 100 km/h, Vaverage is 72 km/h. The drone is plane-like, no…
fakemustache
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Self capacitance of an isolated object

A few times I've been reminded that an object can have self capacitance and it's just not registering with me how this can be so. I'm sure there's a good explanation. Here's the explanation I am usually given but I'm still not grasping that…
Andy aka
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Why wavelength is not measured with a unit of time?

While learning Fourier transforms, I have this little doubt about wavelength. Why is that wavelength for a sine wave, or any other wave, is measured with a unit of distance? If it travels w.r.t. time, why is it not measured as a unit of time? I…
Zaid Khan
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Orange unshielded coaxial cable

A local ISP is installing fiber optic cable for gigabit internet in my neighborhood. Their construction crews have buried runs of empty conduit which I presume is meant to be filled with fiber or Ethernet cables. They have also been running another,…
Joel Croteau
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Best Approach for Long-Distance Sensors

The Project So I have a project idea. (groan) I want to monitor multiple motion and/or ultrasonic sensors to build a simple proximity alert. I want to "deploy" sensors at key points along the perimeter of my home (outdoors). Later, I'd like to send…
Joshua Nozzi
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1 kHz clock over long wire

I will have a wire that will run up to 1000 m with many nodes connected to it. The wire will run along a CAN bus and a ground wire and must transport a 1 kHz square wave 50% duty-cycle clock signal to each node. I will run this from a 3.3 V…
Geoxion
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Methods to accurately move an object across a 2-D plane

This is the opposite/complement of my previous question, which concerned measuring the precise position of an object as it is moved/drawn by someone over a short duration. Assuming I use one of @Rocketmagnet's suggested approaches (probably using…
boardbite
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rangefinder (very long range), ultrasonic or laser... for arduino?

I have a maxbotics Ez1 plugged to an arduino but i was wondering how to build a digital tape measure and to connect it to an arduino, for measuraments longer than 10 feet, maybe 20, 30 feet or more... I see Stanley sells a digital tape for $29.9 at…
Francesco
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real time short distance range finder and visual output

I'm badly visually impared in one eye and find judging distances while walking downhill hard. My goal is to create a real time range finder than can display the distance of the next step(s) while at normal walking pace. for example: walking down a 4…
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