mactro
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Can I control more than 18 servo motor with a Raspberry Pi
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8 votes

Raspberry Pi has only one hardware PWM channel and Linux distribution it runs is not a real time system, so software PWM may be very unstable. You are not guaranteed, that your program will be ...

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Why would a drone need a magnetometer? Are an accelerometer and a gyroscope not sufficient?
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6 votes

The main difference between accelerometer and gyroscope vs magnetometer is that first two give only relative information - you may calculate heading relative to your starting position, but you won't ...

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Continous rotation with cables
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5 votes

There is also ready to use commercial solution from Adafruit, called "slip ring" http://www.adafruit.com/products/736 The only problem is the max speed, which is only 300rpm, but probably you won't ...

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Should I use an arduino to control my balancing robot's motors?
4 votes

If you want to have a good balancing, PID loop timing is very important. Standard Raspberry OS, like Raspbian can't guarantee you any precise timing, so once your loop period may be 10ms, once it can ...

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Obstacle Avoidance while Navigating
4 votes

I think that vector field histogram method should be a good solution here. It's a method of local motion planning (avoiding local obstacles while navigating to a global target). It involves mapping ...

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Can too much input current destroy my motor driver?
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4 votes

You are approaching the problem from wrong side. Current capability of a battery (25C) has nothing to do with that how much current will it actually source. It is the load (motors in that case) what ...

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Relationship between motor torque and acceleration
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3 votes

Based on the calculations, it seems that any amount of torque can get the robot moving That is true only for a theoretical robot moving in vacuum without any friction in its mechanisms. Normally if ...

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CNC: Linear motion without timing belt or lead screw
2 votes

If you want to build something that more or less resembles CNC machine, and use a pen as a tool and draw some pictures, then you will probably be fine (as long as you can do programming and have a lot ...

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What is the top speed of a four legged robot?
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2 votes

Currently the fastest four legged robot is Cheetah by Boston Dynamics that runs 29mph. Real cheetahs can run 70mph and are the fastest land animals. I don't think it would be possible for a robot to ...

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Differential GPS or Simple GPS for Robot navigation and odometry?
2 votes

Do not give up on encoders. They are a great complement to GPS. I don't know what precision you want to reach, or what terrain your robot will operate in, but wherever it will be, encoders will give ...

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Is horsepower related to torque in electric motors?
2 votes

What is horsepower? Horsepower is a measure of power (work done in a specific period of time - the higher power, the more work done), just like watts or kilowatts. $ 1 hp \approx 0.75 kW$ In case of ...

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Fence avoidance for manually controlled robot
2 votes

I think that your problem is rather uncommon, so there may be no solutions ready to use without any modifications. However, you may have a look at "The Dynamic Window Approach to Collision Avoidance" ...

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Accurate Wheeled Robot Odometry
2 votes

First, you can try adding encoders - you don't need to buy anything to do this. Only remember to perform UMBmark procedure first. It will allow you to get much more reliable odometry from encoders ...

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Programming the Odometry of Rover 5
2 votes

Your code won't work as you expect. The problem is that you use only one external interrupt, when you need two - one for each encode. With only one interrupt you will miss pulses from the second motor ...

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Driving a gearbox with another?
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1 votes

I think that on the attached picture, the two things from the right, are a stepper motor and encoder. Notice that both have wires coming out of them. So it is not an example of two gearboxes in series....

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Standard Deviation from one axis to another axis
1 votes

Standard deviation is used to represent probability distribution - in your case if you have $\sigma = 1m$ for forward distance it means that there is ~68% chance of true forward distance to the ...

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which is best IMU for Quad-Copter
1 votes

Both products are based on the same chip - MPU6050. I won't be surprised if passive components used in both modules will be the same too. That means, that from performance side, there will be probably ...

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Permanent Magnet DC Motor Calcuations
1 votes

I affraid you are very wrong with your assumptions. I'm not exactly sure what competition are you going to start in, but take a look at some videos with 3kg sumo robots: Vienna: https://youtu.be/...

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Road Detection When the Robot is Off-Road
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1 votes

You may be interested in what is called "terrain classification" - not detecting the road itself, but classifying different regions of an image taken by the camera as grass, gravel, road, etc. This ...

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Qi Battery Pack
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1 votes

What you are looking for is a Qi receiver, that will allow you to transfer energy from a charging station to your robot. Charging a battery will be a separate task. Adafruit has a module capable of ...

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How to go around in a circle?
1 votes

The distance travelled is directly proportional to speed $s = v*t$, so if you want to achieve specific distance ratio, the ratio of wheel speeds should be the same: $${{s_{left}} \over {s_{right}}} = {...

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Standard equation for steering differential drive robot
1 votes

You named a question "Standard equation for steering differential drive robot", so instead of going deep into your code, I'll try to give you a simple example, how can you steer a differential drive ...

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Stated power for a motor does not equal nominal voltage x current?
1 votes

Take a look at this sample characteristic: http://homepages.which.net/~paul.hills/Motors/ScottMotorCharacteristic.gif Nominal current and voltage are given for the point of maximum efficiency (or ...

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Choosing DC motor: max needed torque vs nominal torque
1 votes

No. The nominal (or rated) torque is a torque that motor delivers at nominal speed. The motor is the most efficient at that point. When you take a look at any DC motor characteristics, you will see ...

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Robot won't work properly, claw will only go one way and will only open or close once per cycle
0 votes

There are two reasons reason for your problem: The main loop is executed very fast - you only check conditionals and assign some values to variables. Total execution time will be probably in order of ...

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Reliability of Raspberry Pi in Wild Life Guardian Drone project
0 votes

There is no definite answer to your question. In any case you should define specific requirements for you system, including: processing power needed maximum power consumption operating temperature ...

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Detect physical touch/hit
0 votes

Why don't just use bumpers? HCR robot is a nice example of a platform that uses this method. The only downside is that they require some force to be pushed.

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Why wouldn't my robot stop?
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0 votes

7.5m/s is pretty fast for a robot, but still not that much compared to speed of sound (approx. 330m/s), so Doppler effect may introduce some error to measurments, but not critical. The point is that ...

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PID control of tank-like robot and IMU
0 votes

Do you have, or can you add encoders to the motors? If you do, I would advise to try to use them as a first step. Encoders allow you to control speed of the motors in terms of their actual rotation ...

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Strategies for managing power on electrical systems for mobile robots
0 votes

Robotics is usually a business of various trade-offs, so there is no ultimate solution for power management, as every robot is different. For example, separate battery for motors mentioned by others ...

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