Questions tagged [sensors]

A sensor (also called detector) is a converter that measures a physical quantity and converts it into a signal which can be read by an observer or by an (today mostly electronic) instrument.

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2answers
126 views

Matrix is singular error in GraphSLAM

I have gone through The GraphSLAM Algorithm with Applications to Large-Scale Mapping of Urban Structures. I implemented the code for GraphSLAM. The fundamental formula of GraphSLAM is $$\mu = \Omega^...
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1answer
188 views

Pressure Sensors for Robot Bumper

I'm building an omni-directional robot base and want to add some kind of low-level obstacle detection. The complete robot will have LIDAR and camera for navigation but I'd like to add something at the ...
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Vısual sensor.camera lenses with a field of view of more than 180 degree

What kind of camera models can be used for lenses with a field of view of more than 180 degree ? Is ıt possible if not why? Are fisheye lenses suitable for this purpose?
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107 views

GraphSLAM data accumulation problem

I try to implement GraphSLAM from this tutorial, The GraphSLAM Algorithm with Applications to Large-Scale Mapping of Urban Structures. I have some doubt while studying this paper. I hope people who ...
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3answers
205 views

How can I get the distance from a robot to a beacon?

I'm planning to create a Raspberry Pi robot to map a room. I intend to use a particle filtering algorithm as one of the central points of the project, that will allow me to work out my position ...
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1answer
50 views

How to create a 3D zone which detects the presence of an object?

I feel this is the most appropriate exchange for this question I hope someone could bring some insight into an area I know very little about. I would like to find a way to detect and log the time ...
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3answers
5k views

What's the difference between a sonar and ultrasonic sensor?

After having read the introductions of the Wikipedia articles about "sonar" and "ultrasonic sensor", it is still not clear to me what the differences between the two are. In the context of robotics, ...
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65 views

Any kind of sensor to detect really fast moving objects with minimum 25 m radius sub 1.000$?

What we are specifically interested in is for our quad-copter to be able to detect and maneuver to avoid (maneuverability is based on our custom algorithms) objects flying towards it with great speeds....
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Gyro Yaw Drift Compensation With The Aid of Magnetomer

I'm getting data From an IMU and a Magnetometer synchronously, my roll and pitch drifts are corrected with accelerometer inside IMU and now I have the DCM matrix ...
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What is the difference between active and passive sensors?

Apparently, there are active and passive sensors. An infrared proximity sensors should be an active sensor, whereas a gyroscope should be a passive sensor. Why is that the case? In general, what is ...
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How can I access the cliff sensors on an iRobot Create 2 via ROS/ Python?

I have an iRobot Create 2 and am currently using the create_autonomy package. Currently, they have cliff sensors as a "planned" feature. I see in the documentation that there are 4 cliff sensors (...
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166 views

What are good options for modifying drones?

I'm apart of a group at my University where we would like to build a drone/UAV and constantly add and modify parts on it. We were thinking of using an Arduino or raspberry pi, but we really don't ...
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60 views

Control geared DC motor based on timing?

According to this video from Khan Academy about electronics of a DVD drive the position of the sled (which moves the reading head) is controlled by a geared DC motor by using only timing and one end-...
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3answers
81 views

How to detect writing on a chalkboard? [closed]

I've got an idea for a simple robot (with an Arduino or something similar) that will play noughts-and-crosses (aka tic-tac-toe) on a chalkboard, so that kids can play against it. It will use a couple ...
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0answers
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Measuring torque of Vex gear shaft - highest accuracy for lowest price [closed]

I am seeking to collect data for my IB Physics IA (internal assessment). My question seeks to establish the relationship between speed and torque by adjusting gear ratios. (I am aware that gear ratios ...
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3answers
877 views

Zero-Point/Home Position/Origin of Absolute Encoder: What is the Proper Name?

I'm writing an academic paper describing the calibration of a system. Part of that system is an absolute rotary encoder measuring the angle of a joint. However, the position at which the encoder gives ...
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1answer
30 views

Finding the manufacturer for a sensor

We're building a smart camera and one of our competitors is using a depth sensor we're interested in using. If we open up the product, is it common to be able to see manufacturer information for ...
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1answer
24 views

Depth cameras with varying illuminations

We realized that depth cameras (IFM) tend to create a lot of noise when exposed in areas with direct sunlight. Are there any approaches to deal with illuminations? Eliminating pixels for instance?
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2answers
141 views

Depth sensing for a pick-and-place robot

I am supposed to design a pick-and-place robot. I have a prismatic joint to go down to a particular depth to pick an object which is located in 2D using computer vision. What is the recommended way to ...
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1answer
46 views

How Do You Program the SR04 Ultrasonic Sensor?

Dear Robotics Community, I am participating in a Robotics tourney that will start in a few weeks. The challenge I signed up for is to deliver and dump ping pong balls to a box. I already have my ...
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1answer
36 views

What kind of sensor do quadcopter uses?

over the last 5 years I had 2 quadcopter as a gift. the first one was basic, manual, I had to manually set the 4 motor speed for it not to crash during take off and I was alway controlling the amount ...
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1answer
397 views

What is the difference between “Sharp Distance Sensors” and “Diffuse Type Sensors” and others?

Searching online I have stumbled across following type of sensors that claim to measure distance. I don't quite understand the difference between them and their pros and cons. Would appreciate if ...
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47 views

How to set sensor output

can anyone please tell me if the sensor output is 0 to +-10V, and i connnect the sensor to differential amplifier to get an output of 0 to 3.3V then what is the input voltage to differential amplifier ...
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1answer
90 views

Self balancing roboter IMU issue

I build a self-balancing robot, at least that what i should have been. now i have tried implementing a complementary filter which combines gyro and accelerometer data, but the problem is that the ...
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1answer
69 views

How to detect books in a bookshelf? [closed]

I need help converting this project to reality for my office that I currently work in. I basically want to have sensors(idk which or what kind) behind a bookshelf in individual racks and have those ...
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2answers
742 views

Scan an Auditorium, Count People, and Display Open Seats [closed]

I'm looking for any recommended approaches to be able to digitally process a room full people, like an auditorium or a movie theater and output the following information: How many people are in the ...
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2answers
619 views

IR pattern projector

I am currently working on a robotics project in which I wish to integrated a depth/object scanner. Now my focus is currently on an IR camera in combination with some sort of IR pattern projector. ...
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How to improve confidence an object is in a particular place

I'm dealing with a problem where sometimes an object I'm looking at using RF signals can appear to be somewhere it's not due to the bouncing of the waves. Currently what I have in place is a circular ...
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1answer
161 views

How do timings affect input, sensor fusion, and output?

I'm programming a quadcopter controller. I've managed to make it fly. But, I'm not sure how to set up the timings schedule for each part of the software. I have several sensors (gyro, accelerometer, ...
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1answer
85 views

Is there a better type of sensor to measure the distance instead of Ultrasonic sensors

We know that the Ultrasonic sensors can't accurately measure the distance to an object that is more than 3 meters away (the distance may vary on brands) has it's reflective surface at a shallow angle ...
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1answer
79 views

How do ultrasonic range behave with two objects at differents distance?

If I have the following objects: A and B. A is a distance "Y" from the ultrasonic sense and B is a distance "x". If B is fix and A is moving, does the ultrasonic sense receive and detects A distance?
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133 views

Kalman filter localisation equations

I am doing mobile robot localisation as a project. Now I stuck in obtaining the equations of EKF localisation. My robot moves straight for 10 seconds parallel to x-axis and robot equipped with 2 ...
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1answer
803 views

If two ir proximity sensors or two ultrasonic sensors are kept face to face , will they give bad readings for interference?

suppose there are two bots.their task is to detect each other and hit one another(as,i am participating in a sumo-bot competition). but if the two of them are using the same kind of sensors like ...
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1answer
54 views

I’m building a robot.what kind of sensor can find the way home

I’m building a robot by raspberry pi and arduino . I want it can charge automatic.I mean the robot can find the charger station by itself. But I don’t know what kind of sensor can make it true. Wifi ...
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2answers
251 views

How to locate an object on a known surface

I am building a small robot on wheels. The robot will be moving at a small speed in a square area of known dimensions. I need to locate the robot and know its position at any given moment so I can ...
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1answer
535 views

High Res Rotary Encoders [closed]

As part of a project I need an encoder to determine the angle that this, Continuous Rotation Servo - FeeTech FS5103R, has rotated through. The resolution needs to be fairly high as I will be using it ...
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1answer
96 views

.launch file associated while using a sensor

What is the general structure of .launch file for using a sensor? For example: 1.Following code is example for using a JoyStick to control TurtleSim ...
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0answers
82 views

How can there be a difference in quaternion values of two points taken from sensors where the orientation is exactly same?

I have two situations- A) One, the body with sensor embedded in it kept at rest. B) Second, the body is at rest for 10 secs, then undergoes some movement randomly and comes back to the exact ...
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2answers
1k views

How to convert raw Pitot tube readings to air speed in m/s?

I'm building a kite flying robot, for which I want to measure air speed. So I combined a Pitot tube with an ADC and connected it to my Raspberry Pi using this tutorial. It seems to work perfect, in ...
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1answer
140 views

Accuracy of 3D scanners in featureless environments

I am trying to 3D reconstruct a room that has been freshly constructed but the walls have not yet been either plastered or painted/wallpapered. So far I have tried using mapping techniques(like rtab ...
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1answer
77 views

How to compute the field of view of a robot when obstacles are around?

Is there a formula to compute the field of view of a robot when it is obstructed by other objects like in this picture When it is a full circle it should be ...
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1answer
45 views

Confused about time systems in ephemeris computation (from GPS subframes)

I am using the gnss-sdr library to compute ephemeris from the GPS message, and to try to make sense of things, I am reading the well-known IS-GPS-200E specification. To compute ephemeris, the time ...
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2answers
284 views

Is it possible that a quadcopter hold height for long time stable only using IMU (without GPS) and barometer?

As we know, we can calculate altitude from barometer readings, and a UAV can hold height by referring to these data. However the real air pressure is varying with many conditions. These variance will ...
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3answers
451 views

Making a robot move straight between two maze walls

Using a PID with encoders, I can make the robot move straight but there is a 0.5 degrees drift and it eventually hits a wall so I need to adjust to center it between the two walls. I have a sensor on ...
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2answers
430 views

GPS message: compute ephemeris data and pseudo-ranges from subframes

I have raw GPS data (see end of the question for details if you think the protocols are relevant), and I need to extract/compute ephemeris and pseudoranges (my goal is to replace the recursive least ...
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1answer
163 views

Why does one IMU axis influence another?

For a home robotics project I just bought a BerryIMU to connect it to my Raspberry Pi. After hooking it up I ran the provided Python code to read out some values while moving it around. If I keep the ...
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1answer
330 views

How can I compensate for pendulum and cart motion when using an accelerometer to detect the tilt angle?

I have an accelerometer mounted to an inverted pendulum (i.e. a cart-pole robot) which I'm using to measure the tilt angle from the vertical upright position (+y direction). If the inverted pendulum ...
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1answer
88 views

Retrieving distance and angle of roobma create2

The goal of my project is to get a real-time location information of roobma. The information includes the x position, the y position and the angle (12 o'clock direction is 0 degree, 3 o'clock is 90 ...
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2answers
397 views

How to measure pull force on a (kite) rope?

I'm building a kite flying robot, in which I've already got some sensors built in. I now also want to measure the pulling force on the rope which is attached to the kite. So I thought of attaching a ...
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3answers
2k views

A sensor that can see glass/transparent objects and surfaces

I am currently thinking about making a robot that will autonomously drive around the place. The place I want this robot to drive in however contains quite a few glass walls. When mapping the area I ...

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