# 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.

294 questions
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### Create 2 Reading Sensor Values

I am trying to solve some Create 2 sensor reading problem that I am having when I came across @NBCKLY's posts (Part 1 and Part 2) that I believe are exactly what I am looking for. I copied his code ...
577 views

### Detect physical touch/hit

I'm making a target to an outdoor robot competition. The target should detect if some of the robot got touched or got an hit automatically. and the target can get hit 360 degree. I'm searching ...
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### Locking the yaw direction of a laser pointer

I have a laser pointer on a handle grip and I'm trying to keep the laser pointer's yaw direction, which can rotate at around 10deg/s. So I have the laser pointer on a stepper motor and an ...
118 views

### Rotate 3d vector value into a single axis using a rotation quaternion

I want to rotate the whole value of a 3d vector into one axis using quaternion rotations. The reason behind is that I want to align the X and Y Axis of my smartphone with the X and Y Axis of my ...
142 views

### Stabilising an inverted pendulum

With the problem of stabilising an inverted pendulum on a cart, it's clear that the cart needs to move toward the side the pendulum leans. But for a given angle $\theta$, how much should the cart move,...
2k views

### Instantaneous velocity calculation from accelerometer?

I am trying derive velocity from accelerometer (MPU9250 in sensor-tag board). I saw lot of blogs which talk about noise and exact estimation problems. I started seeing velocity derivation (integration ...
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### augmenting room magnetic field for smartphone sensors [closed]

is it possible to enhance (or redirect) the earth's magnetic field in a room or house so that one can write a small program that makes smartphones with hall-effect sensors detect more reliably in ...
799 views

### Dead Reckoning: Obtaining Position Estimation from Accelerometer Acceleration Integration

Good day, I have been reading papers about position integration from accelerometer readings. I have consulted this paper from freescale on how that is achievable and this article regarding leaky ...
436 views

### Measuring vehicle's forward and lateral acceleration using a smartphone [closed]

I want to measure the acceleration (forward and lateral separately) using an android smartphone device in order to be able to analyse the driving behavior. My approach would be as follows: 1. ...
564 views

### Mechanical odometer with digital output

I would like to mechanically measure the distance a kids electric ATV traveled. The ATV will not be used with kids but as a mobile robot instead. It has a common rear axle for both rear wheels which I ...
2k views

### Counting number of people entering a room [duplicate]

We are making a project in which we want to count the no. of people entering and leaving a room with one single entrance. We are using IR sensors and detectors for this ,along with an Aurdino. We have ...
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### Building a stationary robot which can talk [closed]

I am a Computer Science major and I only have basic ideas on Robotics. I am planning to build a stationary cubical AI. The main purpose of this bot will be that, it will have a sensor to check if ...
615 views

### Measure weight of an object using a servo

Assuming a quality industrial servo, would it possible to calculate the weight/resistance of a load? Maybe by comparing current draw in a holding position, or by the time it takes to lift/lower an ...
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### Syncing camera with other signals

I am not sure if this is the best place to ask this question, but hopefully someone here can give me some advice. I have a device hooked up to a data acquisition system that can provide sync out ...
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### What kind of sensor I can use to identify which fruit it is (like mango or apple)? [closed]

What kind of sensor I can use to identify which fruit it is (like mango or apple). Moreover, is there any sensor to identify different varieties of apples or mangoes.
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### Sensors for identifying stacked books

I am working on a robotics application that involves moving objects (e.g. books) between several (around 10) stacks. To measure the performance, I'd like to be able to measure which book is located on ...
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### Lag in altitude measurements using a barometer and an acclerometer

I am fusing data from the barometer and accelerometer using a complementary filter. However, there is a considerable lag in the readings which is affecting the Alt-Hold performance. Accelerometer : ...
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### Do walking robots use accelerometers?

My understanding of walking robots (e.g. https://www.youtube.com/watch?v=xJlkBBdyBYI) is that they use a gyroscope to determine the current orientation of the robot, or each joint of the robot. This ...
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### How does one implement a third order complementary filter for estimating altitude using data from an accelerometer and a barometer?

I am working with the CJMCU build of cleanflight on a small drone. As of now, the algorithm for altitude hold uses a first order complementary filter to combine data from the barometer and the ...
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### iRobot Create 2 IR bump light sensor specifications

Can someone tell me where can I find some specifications about the iRobot Create 2 IR bump light sensors? We have an SDF model of the Create 2 that uses the Hoyuko laser range finder sensor and we ...
3k views

### Angle Random Walk vs. Rate Noise Density (MPU6050)

I’ve made a datalog from a MPU6050 (IMU: gyroscope and accelerometer) at 500Hz sample rate. Now I want to calculate the characteristics from the gyro to evaluate the sensor. For the gyro I’ve found ...
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### How can I detect ground collision, for an hexapod robot?

I'm planning to build a small (probably around 30 centimeters in diameter, at rest) hexapod robot, but, currently, it would only be able to walk on even ground. To improve this, I would have to, ...
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### How to have a 'Auto Go Home' feature, like the DJI Phantom 3, on a project built quadcopter?

What should a quadcopter have, or have access to, in order to make this 'return home' feature work? Is GPS enough? What is the approach needed to make this happen? I used a Arduino Mega 2560 with IMU ...
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### Color sensor alternatives [closed]

I am making a white line follower. I am using an IR sensor module based on TCRT5000. I am directly taking the 8bit ADC reading from Arduino Uno and printing the values on serial monitor. I observe ...
220 views

### Discontinuity in device orientation

Why is there a discontinuity in the quaternion representation of my device orientation? I'm using a SENtral+PNI RM3100+ST LSM330 to track orientation. I performed the following test: Place the ...
1k views

### IMU sensor and compensation

Hi I'm using "minImu 9" 9 DOF IMU (gyro, accelerometer and compass) sensor and it gives pitch roll and yaw values with a slope on desktop (no touch, no vibration, steady). Y axis is angle in degree ...
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### Small IR distance sensor that works on black surfaces

Can anyone recommend an IR distance sensor that works on black surfaces? I'm looking for something to use as a "cliff" sensor, to help a small mobile robot avoid falling down stairs or off a table, ...
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### What is the easiest and efficient way to detect human in close range distance and make the robot follow it? [closed]

I am having a thesis right now regarding a robot. My research requires the robot to be attached to linear guide rail. A robot has to detect human in a very close range (of about 2 meters distance). ...
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### Filtering IMU angle discontinuities

I try to measure Euler angles from an IMU, but some discontinuities happens during measurement, even in vibrationless environment, as shown in the images below. Can someone explain which type of ...
186 views

### Crock Pot Knob Turner

I have a Crock Pot with an analog knob and would like to find a way to turn the knob by using and appliance timer. I have no idea where to begin. I need help. Thanks
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### Ways to estimate the drift rate of the gyrometer

I found not so much literature to the topic, this is why I ask here. Does someone know some ways to estimate the drift rate of the gyrometer. I was thinking about basically two approaches. One would ...
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### Where should I put the angle sensor on my cart-pole robot?

I'm using an accelerometer and gyroscope to detect the angle and tilt rate on my two-wheeled cart-pole robot. Is there an optimal height to place the sensors? Should I place them closer to the ...
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### Aligning datasets with drift

I have a dataset that contains position information from tracking a robot in the environment. The position data comes both from a very accurate optical tracking system (Vicon or similar) and an IMU. I ...
3k views

### How to connect ethernet based Hokuyo scanner?

This is a very basic beginner question, I know, but I am having trouble connecting to the Hokuyo UST-10LX sensor and haven't really found much in terms of helpful documentation online. I tried ...
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### Balancing a plate with an IMU offset from the center

I recently bought a IMU . I am new at this. My question: Does the positioning of the IMU matter? Are there any differences between placing it at the center of the plate or if it is offset from the ...
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### “Thermal Imaging” with Arduino and/or Lego Mindstorm NXT 2.0?

I'm trying to build a robot that can be sent into rooms/buildings and detect people using nxt and/or Arduino. In addition to this I would like to be able to view what my robot is "seeing" in real-time ...
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### 2D Positioning of mobile robot [closed]

I am just starting to explore an idea and I am somewhat of a novice in robotics. I am looking to position a mobile robot as accurately as possible on a concrete slab. This would be during new ...
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These days I'm trying to build IR 40kHz long range receiver. I use ir phototransistor. I don't want to use components like TSOP... I need to make daylight filter and intensify filtred signal because ...
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### How to calculate vehicle detection distance

I would like to know how to calculate the distance to each car when I run my application for an autonomous vehicle in real time. In addition I want to know how implement the calculation in C++. You ...
117 views

### Air hockey with a robot as an opponent

I'm not sure if this is the right place to post this but here goes. So, as the title states, I'm planning on building a desk that doubles as an air hockey table which has a robot on the other side. ...
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### Wall following using hokuyo lidar and sharp IR sensors

I have a mobile robot and I would like it to follow the walls of a room. I have: A map of the room. Wheel encoders for the odometry. A Kalman filter for fusing data from wheel encoders and IMU. A ...
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### recommendation for really high precision attitude measurement sensors

I am new in this field, I am looking for some high precision gyroscopes and accelerometers for attitude measurements.The precision requirement is around 0.2~0.5 deg/s dynamic. I have done some ...
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### Positioning Sensor

I would like to locate the position of a stationary autonomous robot in x-y-z axis relative to a fixed starting point. Could someone suggest sensors that would be suitable for this application? I am ...
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### Simple Sensor Fusion for pose estimation

I am currently working on a balancing robot project, which features fairly low-cost sensors such as an 9-Dof IMU with the measurement states \$\textbf{x}_\text{IMU} = \left[a_x, a_y, a_z, g_x, g_y, ...
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### Which sensor type most accurately measures position?

We're building an 6dof joystick, and we need to accurately measure the displacement of our central device. We can easily use a mechanical connection to the edges, but there has been some discussion ...
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### How does the cliff sensors on ROOMBA work through a glass wall?

I want to use IR sensors to detect whether my dustbin is full but I want to protect it from outside dust. I am planning to use the IR sensors on Roomba. How are they working despite a plastic wall? ...
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### Sensors' field of view in car driving

I want to develop an autonomous driving RC car. For detecting obstacles, I plan to mount 3-5 ultrasonic sensors in the front and in the back the car. What is the minimum necessary combined field of ...
738 views

### How to localise a underwater robot?

I am building an autonomous underwater robot. It will be used in swimming pools. It should be capable of running in any normal sized pool, not just the pool in which I test. So I cannot rely on a ...