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Misc / NEW Linear Actuator Kit
« Last post by ServoCity on March 04, 2019, 04:19:12 PM »
Looking to build a linear actuator to your own specifications? Check out our Linear Actuator Kits

Misc / data science course in pune
« Last post by AnshumanTripathi on March 04, 2019, 12:28:32 AM »
Which is the best Data Science Course in Pune?
Electronics / Re: Battery building?
« Last post by headrc on February 27, 2019, 09:43:11 AM »
I am going revive my own topic here ....which did not receive a response before.  I am still curious regarding this ...anyone care to respond?  Thanks for a great forum .... Richard
For Sale / Re: Misc. Robotics pieces for sale
« Last post by BonzaDog on February 16, 2019, 04:14:06 AM »
What have you got , I am interested in parts.
I do need a chassis about DIN A4 size or bigger.
Post to Germany
Hi all,
I am in need of suggestions of how to build an automatic button-pusher for my Android phone. I need it to work automatically while I am driving.
Any suggestions?
Thank you in advance,
Misc / Don't miss out on 15% sitewide - Now through 02/15/19
« Last post by ServoCity on February 14, 2019, 09:13:13 AM »
15% off our Entire Site!!!

im looking to pierce a co2 canister without using pyros or a conventional motor. the task is to occur underwater and the package needs to be very small and as simple as possible to avoid excessive maintenance and misfires. i have nailed it down to two methods. either pushing a sharp object into the canister via a peizo linear actuator or cocking a sharp object under tension of a large spring and releasing it through a mechanical trigger mechanism.

problem with the piezoactuator idea is they only travel 0.05mm max. and the spring idea is dangerous and could fire if knocked or dropped.

if any one has any other ideas id be happy to hear them. it doesnt look like this forum gets much action so il put this here and see what happens if not il just move on.
Mechanics and Construction / Re: Assisted firing device
« Last post by freelectron on February 10, 2019, 09:09:24 AM »
having a cheap chinese microcontroller firing a lethal weapon for a handicapped individual....what could go wrong.
Mechanics and Construction / Re: Trumpet Playing Robot... how does it work?
« Last post by TrmptPhysics on February 07, 2019, 01:08:29 PM »
Resurrecting a very old thread here, but I was researching this topic and have some new information.

It was said, "the lips vibrate/buzz to produce the sound, so how do the robots make sound?" There is a fundamental property of physics that must be understood to know HOW the lips vibrate. When a trumpet player plays a note, they DO NOT make their lips buzz. Their lips vibrate in sympathy with the motion of the air. Meaning that when air is passed through the lips and into the trumpet, a standing wave is created within the instrument, and the lips vibrate in sympathy with the motion of the air. In a standing wave, there are two points of maximum compression/tension created, and these are called nodes. The wave moves between these two point, and depending upon the length of that wave, you will get higher and lower notes. As the wave/air bounces back to the lip, they vibrate and make tone.

Now, a trumpet players lips vibrate faster or at a greater rate when the pitch is higher. This is actually a result of the air moving faster to create the higher tones. There is also an aperture in the lips through which the air moves, and this changes size in relation to the pitch and speed of the air. Basic take away, lower notes, slower air. Faster notes, faster air. Lower notes, a slower rate of sympathetic vibration in the lip and a more open aperture. Higher notes, a faster rate of sympathetic vibration and a smaller aperture.

The way this robot works; a synthetic mouth is created. Most likely using latex and a basic "dental structure." The mouthpiece is placed on these "lips," and internal air compressor moves air through the lips and into the trumpet and tones are produced. One of the most important things to remember is that the trumpet is a static instrument, it cannot produce sound with out air and sympathetic vibrations from the lips. If you were to take the instrument away from the robot's "mouth" and allow the air to continue moving through the robot's "lips," you'd simply hear a hissing sound. Again, the vibration is created in conjunction with the motion of the air and the standing wave within the instrument.

So, basically the robot "blows" air through the trumpet the same way a trumpet player does. The difference is there is no muscle structure or creative process in the "mind" of the robot, and therefore it cannot manipulate it's sound to produce anything beyond a very basic tone. I hope this helps those of you curious about the trumpet robot, and I'd love to know if there are more questions! If we really want to go down the rabbit hole, we can talk about the uproar this little guy created within the trumpet pedagogy community at the time of his release :)
Misc / New- HS788HB Servo
« Last post by ServoCity on January 11, 2019, 10:32:36 AM »
The Hitec HS-788HB servo is based around the long-time favorite, the HS-785HB. This new model was created with a 25 tooth output spline in order to conform with the majority of the hobby servo market.
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