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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2
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2answers
3k views

360 degree ultrasonic beacon sensor

Basically, I want to detect an ultrasonic beacon in a radius around the robot. The beacon would have a separate ultrasonic emitter while the robot would have the spinning receiver. Are there any ...
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1answer
506 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. ...
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1answer
26 views

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 ...
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2answers
162 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,...
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1answer
133 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 ...
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1answer
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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1answer
37 views

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 ...
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2answers
689 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 ...
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1answer
177 views

Shallow underwater wireless sensor network [closed]

I need to make shallow (max 2m) underwater wireless sensor network. Data payload is about 10kB/s. I know that VLF band (~3-30kHz)could be the best solutions for that, but cause of time-to-market I ...
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1answer
984 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 ...
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1answer
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 ...
1
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1answer
81 views

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 ...
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1answer
744 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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1answer
69 views

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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3answers
107 views

Wearable Accelerometor

I've worked with wiimote accelerometer, but I think now I want to move past that. Mostly because I want to have a wider range of available gestures and I think that using only one accelerometer has ...
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1answer
109 views

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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2answers
465 views

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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2answers
275 views

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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2answers
329 views

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 ...
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2answers
218 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
2
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1answer
121 views

Best strategy for area scanning using little sensing bots

I'm currently working on a school project about simulating robots scanning an area, but it has been a struggle to find what strategy the robots should use. Here are the details: I am given a certain ...
3
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1answer
175 views

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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4answers
2k views

Quadrocopter first build: how to tell if components play well together?

I'm building my first quadrocopter, and I'm trying to come up with a parts list that is suitable for a first build. I will use this to learn how to fly a quadrocopter manually (lots of crashes!), ...
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3answers
1k views

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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3answers
264 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 ...
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3answers
332 views

Detect polyethylene

First of all, I am in high school[to tell you that I am a newbie and lack knowledge] What I want to achieve for now is a thing that can differentiate between poly bags[polyethylene] and other stuffs. ...
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1answer
476 views

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 ...
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2answers
2k 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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3answers
3k views

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, ...
0
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1answer
522 views

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). ...
4
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1answer
706 views

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 ...
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4answers
2k views

Why do 3-axis accelerometers seemingly have a left-handed coordinate system?

Careful inspection of page 35 (figure 58) of the ADXL345 datasheet shows that under gravitational loading only, the chip uses a left-handed coordinate system. My own experiments with this chip ...
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1answer
73 views

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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1answer
212 views

“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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1answer
274 views

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 ...
2
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2answers
91 views

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 ...
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1answer
295 views

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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0answers
98 views

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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1answer
53 views

IR 40kHz receiver [closed]

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 ...
-1
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1answer
599 views

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 ...
4
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2answers
124 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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1answer
306 views

Measuring angular displacement using the TI-SensorTag

I've looked around but can't find the answer, to what I hope is a simple question. I'm working with a TI-SensorTag, and I want to be able measure the rotation around the unit's Z-axis. Basically I ...
2
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2answers
101 views

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 ...
4
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1answer
798 views

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 ...
0
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1answer
52 views

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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4answers
4k views

Robot docking for self-recharging

I want to build a simple obstacle avoider robot, but this time I want it to be self-recharging so I am building a dock for this purpose, so I want it to be able to locate the dock and go for it when ...
5
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1answer
1k views

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, ...
6
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4answers
271 views

How to find out how far a motor has taken a vehicle?

I have a small motorized vehicle with gears as wheels running up and down a track made of gear racks. How can this robot know when it has run half the track? And what's the best method to keep it from ...
2
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2answers
109 views

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 ...
2
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3answers
326 views

Position and Object Data Tracking [closed]

For a class project, I'm working with a weight stack: I'm trying to simultaneously measure: the position of a moving weight stack the value of the weight based on a calibrated/preloaded position in ...

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