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61
Electronics / Re: Servo Surge Capacitors
« Last post by cyberjeff on August 18, 2015, 07:43:57 PM »
Sounds like you're making a Quadroped, or something else that stands up on power up.

Staggering the power-up would be the easiest way of doing it.


Yes, that is exactly what I am making. A cat like quadruped.

My thinking is to to hold it by it's spine on power up so that it goes to either a "sit" or "down". Actually my thinking is a bit warped at the moment as I've been studying quaternians.
62
Electronics / Re: Servo Surge Capacitors
« Last post by ProgressiveAutomations on August 18, 2015, 05:36:52 PM »
Sounds like you're making a Quadroped, or something else that stands up on power up.

Staggering the power-up would be the easiest way of doing it.
63
Mechanics and Construction / Re: Robot Construction Log
« Last post by mklrobo on August 18, 2015, 02:56:15 PM »
 ;D Hello!
In reference to the audio filters;
You can use roll off filters, such as high pass, and/or low pass. These can be simple
resistor capacitor combinations. If you want a specific frequency to pass, with a high Q,
you can use a twin - t operational amplifier circuit. To make sure your circuit is performing
like you want it too, you would need an oscilloscope. I would recommend a Velleman
PC oscilloscope, PCSGU250.
12 Mhz bandwidth, with oscope, function generator, spectrum analyzer,
transient recorder, and bode plotter. At $150, quite a deal, compared to the competition and their
functionality. Good luck!  ;) :) :D ;D
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Software / Re: EM parking sensor
« Last post by mklrobo on August 18, 2015, 02:49:10 PM »
 ;D Hello!
Insofaras programming the Atmel, I am still working on that.  :'(
However, I have learned that you can extract info from the MCU, if the
"fuses" are not "set"; of the MCU is not "locked". These features are
available to be looked at in the AVR studio software. The documentation
for this is buried in the help section. If none of these options were
used, you may have a chance at securing the code. A great opportunity to learn!
 ;D ;D ;D
65
Electronics / Re: Servo Surge Capacitors
« Last post by cyberjeff on August 18, 2015, 02:05:49 PM »
From my experience with motors, they spike for a very short amount of time.  You may only be getting a current spike for 0.1-0.2 seconds, so smaller caps may suffice.

What's the likely hood of every servo spiking at once?

Would seem most likely at turn on.

I think I'll isolate the microcontroller (DUE) with a diode and a cap and not worry about the servos too much. Otherwise I can attach one at a time on startup with that .1 second delay between them. ESR on small supercaps appears to be relatively high so might not be worth the effort.
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Mechanics and Construction / Re: Robot Construction Log
« Last post by FIFO on August 18, 2015, 01:22:16 PM »
    I have made quite some progress on the robot. I have constructed the head and have mounted the sonar PCBs and ultrasonic transducers into it. I have also constructed most of the circuitry for the voice command system. I have also run into several new problems. I have found that the steering gearhead motor keeps stripping its teeth. I believe this is happening because the servo system causes the motor to start and stop rapidly and the momentum of the steering column causes the motor to turn when the motor is being electrically braked, and the force causes the gears in the motor to strip. I could solve this by getting a gearmotor with stronger gears, or get one that has a higher gear reduction and therefore turns more slowly, but that would mean that I would have to machine new mounting brackets and a new coupler to fit the motor. Instead I am probably going to design a PWM circuit so that I can run the motor at slower speeds.

    I also ran into some difficulty with the voice command system. As explained in a previous post, the "voice command" system works by comparing the frequency of notes sung by the operator. The problem I have run into is that the circuit "thinks" that lower notes sung by the operator are much higher than they actually are. This is because the circuit is counting the frequency of the strong harmonics present in the lower notes of the human voice. I need to figure out a way to filter out the higher harmonics of a lower note, but then not filter out higher notes sung by the operator.
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Mechanics and Construction / [advertisement] New Magnets from ServoCity
« Last post by ServoCity on August 18, 2015, 09:22:58 AM »
These powerful and versatile magnets create an easy way to connect your Actobotics parts with the counter sunk holes, used in combination with counter sunk screws. These are also available in both polarities; in the .5 diameter and 1 diameter versions.


https://www.servocity.com/html/magnets.html

Video Link: https://youtu.be/T9jMZOcmvdI
68
Software / TLC5940 + Servos in microseconds control???
« Last post by ecaits on August 18, 2015, 03:04:47 AM »
I have started to work on TLC5940NT to control the multiple servos through arduino uno.
Generally we are providing rotation of angle by below given program line.

tlc_setServo(SERVO_CHANNEL, angle);

But I want to provide command in form of ServoWriteMicroseconds to measure the exact rotation of angle.

But in TLC library, there is no such a command.

So how can control the TLC servo by microseconds???
69
Mechanics and Construction / Re: Pan/Tilt joint
« Last post by Gertlex on August 17, 2015, 10:43:35 PM »
I'm  thinking that the Axon must support C++ as well as plain C, although I could not find that out. I have a hard enough time with C++, not having objects and classes makes controlling multiple servos tedious work.

You can program the Axon in C++.  The Webbotlib Libraries/Suite are the best supported approach for that.
70
Electronics / Re: New to robots
« Last post by ProgressiveAutomations on August 17, 2015, 03:34:35 PM »
You can use H bridges to get precise control of the motors.  You would need 1 H bridge per motor, and you want H bridges that can handle at least 20 amps.  You can find a few different H bridges on our website, http://www.progressiveautomations.com/control-systems/plc-controls . You might get lucky with our WASP motor driver, but that has 10A continuous current, so it would be close.  The Scorpion XXL can control 2 motors, each at 20A continuous.  That would work better.

As for operating the bot wirelessly, you could try an RC controller. That would work easily for the drive motors, you may even be able to find one that's plug and play with the Scorpion. If it's not plug and play, you can use an Arduino as a brain, and input the receiver signals from the RC controller to the Arduino, process them, then output the control signals to the H briges to drive the motors.

Adding 5 extra channels for the arm could be harder.  The easiest way I can think of (though its still not very easy) is to make some sort of bluetooth control and control it with a smart phone.  That would be some advanced programming though.

Another way would be use the switches on a RC controller.  Most controllers I've seen that have lots (5+) of channels, have a bunch of switches and buttons on the controller.  You could use the main joysticks as drive control for the motors, then when you switch a switch the controls change, and now move the arm.  This would be easier to program then bluetooth control, but moving the robotic arm intuitively may be more difficult, because you'd be most likely moving one or two motors at a time, rather then the arm as a whole.  But that depends how you build the arm.

Either way, I've made a fair bit of assumptions about your project, if you can share more details we can help you further.
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