Reusable Burst Disc? Answered

So I had an Idea for something, but the problem is that it would need a burst disc or rupture disc, which have to be replaced after each use. What I was wondering is if there is some way to make them be able to be used multiple times, or something that could act like a burst disc (eg releasing a large amount of pressure very quickly) that could be used in quick(ish) succession?

Question by Mecknavorz   |  last reply


A little help with identifying Ceramic Capacitors?

A friend asked me to fix his tv's power supply, and i accepted the challenge. Upon closer inspection of the circuit board of the power supply, i saw that a resistor bridge, a rectifier, a diode, a capacitor and 2 power transistors were blown. I purchased the appropriate replacements, and as i was about to install them earlier today I saw that two ceramic capacitors are blown. One of them has '684J' printed on it, the other has "SCK 206 or 296" printed on it I need a little bit of advice on what replacement capacitors to buy, or if i should take them out of the circuit. I could leave them out, because they seem to hook up to a rectifier and then to a transistor, but i would rather buy the appropriate replacement capacitors. Thanks!

Topic by Sandisk1duo   |  last reply


does anyone know if the tippman TMC paintball gun can be converted to automatic or burst fire?

I just got a tippman TMC and was wondering if there was a way to convert it to automatic or burst fire

Question by ColinB96   |  last reply


How to choose 1 out of 14 or so images for 4000 burst shots? Answered

Oops- tried to take a time lapse but the shutter was set on burst (40fps), so every time it took a picture it took about 14 pics in bursts.... The camera took around 3000 or so shots on this burst setting, how can I take out a picture every 14 pics or the shots automatically? Is there any  "picker" software, mac or pc, that will take 1 out of 14 images repeatedly automatically???? thanks for helping me fix my dumb mistakes- again ;-) -A907

Question by astroboy907   |  last reply


How is Greek Fire made? Answered

 It might be known as something else.  In the days of wooden ships bombs of this ( not the fuse kind) were thrown onto the opposing ship.  When the container burst or opened, the air ignited the chemicals inside and it burst into flames.?

Question by rookie1   |  last reply


is there a to use the big burst of energy from a capacitor to have enough energy to make a photon or ray gun of sorts? Answered

How powerfull would a capacitor need to be to do this, an what is the relation between volts and uF?

Question by mikmkt93   |  last reply


How can you make an Icon that when you click on it, it will make the screen look like its bursting into flames??

Ok, so i have a mother who likes to keep me aways from the internet. So i want to make an Icon that looks like the Icon of the internet button and make it look like the computer is either bursting into flames or somthing that looks soo real. Its the only way she can stay away. Can you help me on this??

Question by Tech_O_Candy 


Can you use an intermittent bursts of air to control the output RPM of a Tesla Turbine?

I've seen plenty of these projects using a constant stream of air to turn the turbine. Surely with the combination of rotational inertia and an intermittent jet of air a constant rotational force could be sustained whilst conserving the compressed air available?

Question by    |  last reply


Problems with Nikon D7000 Continuous Shooting?

When I put my camera on shutter priority and continuous high, the camera takes the pictures but the images come out VERY VERY dark I haven't changed any settings in the camera (I have the same problem in continuous low option as well) what is the problem? am i missing something? is there a trick? what should I do? p.s. i am unable to do burst shooting when the (built in) flash is on (is this normal?)

Question by rptech   |  last reply


Is it possible to make a burning lazer gun and how?

I want to make a burning lazer gun that lets out a burst of lazer. I want it to  at least light a match.

Question by Jewson 


What is the best way to generate and store power from short bursts of a spinning wheel?

I have a wheel that spins up to 508RPM for a period of approx 20 seconds. It does this every 2 minutes for approx 20 mins then it stays motionless for up to one hour. How can I generate and store enough power to power a wireless router and slr digital camera charger? The budget is up to $1000 USD.

Question by olfgwalk   |  last reply


High Altitude Balloon: Could you steadily release helium as you gain altitude to prevent bursting?

I have recently been researching privately made High Altitude Balloons. Making something that can travel a third of the way to space while taking pictures and/or measurements sounds like a very cool project. Typically these balloons pop before reaching anywhere near space. While researching I had a small "Eureka!" moment for a potential fix for this issue. It might be possible to take these balloons farther up if you slowly release helium in correlation with altitude. Perhaps by measuring the size of the balloon as it expands upwards and out, and then releasing helium with an electronic valve until it returns to proper size.  I have the nagging feeling however I am not considering everything though. Is there some principle of 'The way things be' that prevents this method from working correctly? Would the lift of helium increase with distance from the earth significantly enough not to drag the craft down when you release helium? Or would the helium loose its effectiveness the thinner the atmosphere became? Any help I can receive in being unflummoxed is greatly appreciated.

Question by TheIronHobo   |  last reply


what to do with 30 high voltage camera flash circuits?

I need ideas to use 30 camera flash circuits, as i have bulk i want to use them in an array or all at once.As HiVoltage burst or light does not matterPersistance of vision?Starburst camera jammer?

Question by oliverkellow   |  last reply


Can someone tell me if this idea will work.?

I am wanting to make a low powered soldering iron and I want to find out if using a sudden burst of elecricity from some sort of capacitor would be able to melt the solder. I have all the tools to make it but I dont know if it would work. Thank you in advance.

Question by nattyclem   |  last reply


Electric Lady - High Frequency Power Supply?

I saw an electric lady in a travelling sideshow. The type where she throws sparks from the hands, makes paper  burst into flames and causes bulbs to light by holding them. I'm assuming they are using a high frequency power supply (very low amps), and I was wondering if anyone has built one and if there are any good schematics on line?

Topic by Divet   |  last reply


no fog

  I dont know the mechanics fog machines,so heres a problem u probably already heard,or know about.. I have a cheapy  400 watts Gemmy (about 6 or 7  years old). I pulled it out of the attic thinking it needed a good cleanout before halloween. I mixed up a 50/50 bottle of white vinegar and distilled water - turned it on and got one good 20-30 second burst from it.On 2nd burst a little leftover came out then nothing.Still heats up hot and I can hear pump humming when i trigger the remote. Next, I empty the tank and tried straight fog juice and still nothing.I emptied the tank  and cleaned the tank filter tried it all again and still nothing...Could it be somewhere in the solid copper tubing from the pump to the heater and how do I clean that?   I did however store it without fog juice in it..(empty),could that a cause of problum ?  Please help.. TKS.

Topic by ron de   |  last reply


Is it feasible to use plastic as the material casing for a miniature fan driven jet engine?

I would like to use an old cpu fan and some old 2 liter soda bottles to experiment jet engine designs. Using lighter fluid for the fuel and probably running the engine in short bursts just to measure thrust output, it should be strong enough to survive at least several runs without dramatic failure right?

Question by    |  last reply


Finding out the value on a rc crystal?

I have a rc kit and need to know what the reciver frequency is (so I can get a Transmitter). The crystal has nothing saying the frequency. The part number on the crystal is... 26 800 6BF-15 any help would be apprecated. Thanks. PS: While writing this My brother was playing with another Rc kit and it burst into flames.

Question by David97   |  last reply


Can I fix my 400w fog machine?

I dont know the mechanics fog machines,so heres a problem u probably already heard,or know about.. I have a cheapy  400 watts Gemmy (about 6 or 7  years old). I pulled it out of the attic thinking it needed a good cleanout before halloween. I mixed up a 50/50 bottle of white vinegar and distilled water - turned it on and got one good 20-30 second burst from it.On 2nd burst a little leftover came out then nothing.Still heats up hot and I can hear pump humming when i trigger the remote. Next, I empty the tank and tried straight fog juice and still nothing.I emptied the tank  and cleaned the tank filter tried it all again and still nothing...Could it be somewhere in the solid copper tubing from the pump to the heater and how do I clean that?   I did however store it without fog juice in it..(empty),could that a cause of problum ?  Please help.. TKS.

Question by ron de   |  last reply


Exploding Glass Tears-- forgot the name, but it's called "(some Austrian city) tears." ? Answered

You get a super-strong tear-shaped glass object that's incredibly strong-- stood up to repeated hammer blows on the bulb end. But when the "tail" is snapped, it bursts into powder. There's a wikipedia entry, but I need the name to find it again. I'd like to try it, but I need better info to avoid long trial/error sessions with hot glass.

Question by Sawgrass man   |  last reply


Heat absorbing glass question Answered

I'm taking apart a Kodak 4200 projector. The lamp assembly includes a piece of "heat absorbing glass".  The manual says not to touch it unless wearing gloves, to keep it covered when out of the projector, and that it may shatter.  Being clueless, this sounds spooky.   Is it dangerous, or will I just wreck it for projection if I get fingerprints on it?  Most glass shatters, but is this going to spontaneously burst into shards?  It's not going back into the projector.   Is it useful for anything, or should I wrap it in foil and toss it in the garbage?

Question by mole1   |  last reply


Is it possible to connect multiple grounds or (-) into a switch while keeping the power sources and outputs seperate? Answered

Heres a picture of the concept i need to know i would be doing this with more power sources and outputs is it possible and is each battery's power isolated from the others even though i can switch them both off! This is vital because im working with diodes and one burst of power and flush goes my money any help is appreciated greatly. Thank you!

Question by TheIronHobo   |  last reply


Help me connecting capacitors???

Friends i need help in connecting capacitors to get a burst of current in following cases:- capacitors of same V but different uF(i know thats not a 'u' but i dont know how to type it) capacitors of same V and  uF capacitors of different V but same uF.                                                                                & also if you can suggest me a book, article,instructable ect. so i could do it next time on my own. And i know how capacitor works but just want to know how to practically use them.                                               

Question by Atul009   |  last reply


Help designing/building High Altitude Balloon cut-away system

I am working with my kids to put together a High Altitude Balloon launch to take pictures. I am stuck at building a system to cutaway the balloon in the event that it does not reach burst altitude. Any help, or resources that would get me going would be appreciated. I am leaning towards a system that can me initiated from the ground via ham radio, as well as timer based in the event of communication failure. Thanks!

Topic by joatman   |  last reply


How to make ARDUINO aware of using a MOTOR by other item/pcb ??? Answered

Hi. I would like to know, how can I get the information to ARDUINO ... that other item/pcb has turn on a motor ??? The PCB that the cables are coming from to the motor is power by one AAA battery. When you turn on the pcb, it sends short bursts to the motor, so it vibrates every second (for half a second). Now I would like to know, how to connect the arduino to the motor, so that the arduino would know when the motor is on ??? Thanks

Question by zholy   |  last reply


How can I modify a PIR so triggers faster, and then fades out?

I want to make a motion-activated light that turns on immediately when someone walks by for about a second, then fades out for about one second. Most PIRs seem to stay on for a minimum of 5 seconds, then just cut off. I'm looking for a quick burst, quick fade. I'm very new to working with electronics, but my guess would be that instead of modifying the PIR itself, the PIR would be triggering something else that would be doing the timing/fading.

Question by tim_finnegan   |  last reply


Controlling motors with my Arduino

Hello, i received an arduino (duemilanove) as a gift for christmas so im still kind of a n00b, i was wondering if it was possible to control motors directly from the arduino for an upcoming project? i would buy a motorshield but im not sure if its compatible with the duemilanove and if i do buy it i wont be able to get it until around easter I need to run two-three motors in bursts repeatedly (ex. Motor 1 for 1 sec Motor 2 for 1 sec motor 1 for 1 sec...................... you get the gist of it) Thanks in advance, Firezone 

Topic by firezone   |  last reply


Air tank testing

I have recently acquired a 25 litre compressor on which the motor was seized so my plan is to replace the motor and pump with a couple of fridge compressors however the tank is more than 10 years old and although I cannot see any damage is their anyway to check it is safe to pressurize to 8 bar? it has 175PSI stamped on it so I assume its designed with that as the maximum working pressure but I want to know if I can get it checked as I don't want to blow myself and my garage apart if it bursts I'm in the UK

Topic by patrickshadow   |  last reply


How do i make a "Book of Fire"?

Also called a "burning book", i saw this trick in a chem class once. the prof took a book off his shelf, plopped it open to some pages in the middle, then turned the page, making sure it rubbed along the page underneath (presumably for friction), then the pages burst into flame. really, the air slightly above the pages was the burning component, because he then slammed the book shut and CAREFULLY reopened it to the same pages to show they were undamaged. i can't figure out quite how it's done.

Question by s1rus   |  last reply


How to test an analog tv screen ?

I have a vega 542 TV that I recently purchased at a flea market . I took the outer cover off to find a mass of circuits, all labelled in Russian that I have no idea what they do. This small tv has an analog screen which I have no idea how to test. When I connect a power supply that is 3 v lower than recommend and was rewarded with a burst of static from the speaker and a high pitch hum from the circuits but a completely black screen. If you do anything that can help me get this working I'll be very pleased.

Question by csimpkins2   |  last reply


water inline low pressure gauge at output

I don't know if they sell them , water Inline  pressure Gauge  made for 5 lbs and under, or is there an easy way t to make one, doesn't have to be inliine, it just needs to  measure the psi at 5 gallons and at 1 gallon.. Even A balloon that burst at 3psi would be good/. it is for a medical device. i spent the last year going crazy cause it was defective brand new.  it was putting out the correct  pressure at the start, 5 gallons, at the half way point it was putting out about half the pressure, didn't know it, almost had  surgery because of the poor results thanks for any ideas

Topic by escapefromyonkers   |  last reply


What size of resistors should I use? Answered

I'm going to build an 8x8x8 LED cube and I am confused about what resistors I should get. Here is a link to the blue LEDs that I bought: http://www.ebay.com/itm/110942426746?ssPageName=STRK:MEWNX:IT&_trksid=p3984.m1439.l2649. This step https://www.instructables.com/id/Led-Cube-8x8x8/step14/Choose-your-resistors/ says to use the burst load of the LEDs but the chart on the item page is somewhat confusing to me. I know that with the resistance equation it would be R=3.2v/0.02A but I don't know if that is the right mA. I am pretty new to electronics so any help is appreciated.

Question by Arya42   |  last reply


Paper Batteries

Has anyone read anything about the up and coming Paper (thin) batteries ? Paper Batteries: A paper battery is a flexible, ultra-thin energy storage and production device formed by combining carbon nanotubes with a conventional sheet of cellulose-based paper.A paper battery acts as both a high-energy battery and supercapacitor, combining two components that are separate in traditional electronics. This combination allows the battery to provide both long-term, steady power production and bursts of energy. Non-toxic, flexible paper batteries have the potential to power the next generation of electronics, medical devices and hybrid vehicles, allowing for radical new designs and medical technologies.What do you think? Will it replace these monsters one day?

Topic by Goodhart   |  last reply


What is the best design for an electromagnet in a pulse engine?

I am a complete bigger to all magnets, electromagnets, and electronics in general. Recently I've had an interested in different electric motors and have been looking into trying to make a pulse motor that is both efficient and powerful. To do this I want to be able to have the best arrangement of the magnetic fields of the neodymium magnets on the spinning disk and the electromagnets on the outside. I started playing around with the magnetic calculator found on https://www.kjmagnetics.com/calculator.asp but I don't really know what I'm looking at, just that different shapes and sizes have different fields and strengths.  Since a pulse motor is built by using an electromagnet to repel a neodymium magnet, what would be the best design for a strong burst electromagnet in the direction it's repelling the neodymium magnet? Also, what would be the best shape for the magnet to have the biggest repelling effect from the pulsing electromagnets? 

Question by AlanR18 


is there an easy way to manually operate a cd tray?

Im in the middle of automating my trash can (i know i can just buy one, but what's the fun in that?) and i got the proximity sensor part to work, but i cant think of a way to turn a short burst (in the sensor test circuit i had the led on the output blinked once when my hand got close yay!) into a signal that would power an old cd motor until it opened, pushing the trash can lid open, wait about 10sec or so, then apply reverse polarity for 2sec or so until it closed. i might be able to use a microcontroller to do this, but im just getting into that and i don't want to use one for this unless there isn't another way. if it's relevant im using a 555 to generate a 38khz pulse to an ir led picked up by rpm7138. any ideas?

Question by the judge   |  last reply


How to network Windows Vista and Windows XP? Answered

OK, I have (for now)  2 Windows Vista Laptops (wireless) 2 windows xp laptops (wired) 3 Windows XP desktops (wired) 3 Windows CE compaq evo thin clients (wired) ((not necessairly important)) Well I want to network these in an file sharing fashion, so I can share media, files and printers. I am using a 8 port Netgear hub and a Linksys Wrt54GS version 7 (I think) that are bursting at the seams. Unfortuatley  my Vista laptops refuse to join my network, I have tried to make a netowrk disk from my XP computers and transfer it to my laptops but with no avail. Any help would be appreciated (with the exception of DAMN U HAVE ALOT OF COMPUTERS, that gets alittle tiring)

Question by bwpatton1   |  last reply


programmable micro-controller for multi-stage coil gun?

Hey everyone, right now I'm in the early design stages for a large, two coil, coil-gun that I'm going to be building sometime in the next few months ( I need to gather the money for the project lol) Anywho, I'm looking for a programmable micro-controller that I can easily adjust ( I know some programming, mostly C++ and java script) That can send a low voltage signal to two separate thyristors at a certain interval ( probably a few milliseconds apart, but maybe even lower), or not send a signal to one at all, if needed. On a side note, one thing I can't find anywhere, for maximum velocity, should the two coils have the same, or different strength ( aka, should the second give off a stronger magnetic burst then the first, or should they be the same. If anyone knows a better way to do this than using a micro controller, then please feel free to tell me. 

Question by epicbobman52   |  last reply


What is that thing ?

Hello ! So, here is a series of pictures that my brother took about two weeks ago (2007/08/29, at 23:00 french local time). He was going to sleep in his van when he saw a weird blinking/moving light at the horizon. He put his digitalcamera (Fujifilm Finepix S5600) on his tripod, quickly configured it, extended the zoom to the maximum (optical + digital zoom) and took two series of photos with the burst mode. Then, he tried to quickly reconfigure his camera and to take one more manualy. Facts : His tripod seems quite stable : stars don't move from a picture to an other. As we can see thanks to the last picture (a photo of an other part of the sky took with the same parameters), the stars of the two series seems not to be "dead" pixels of the CCD sensor. Known parameters : ISO 400 shutter speed : 1/2.5s. He says he doesn't know what it is. With my other brother, we tried to find an explanation, but so far, we failed. What do you think about this "UFO" ??

Topic by chooseausername   |  last reply


Seeking advice on boosting range of fm transmitter (from a kid's toy)

Hi all, I just bought the Smartlab: You Build It - Rock Star Microphone toy from a Goodwill. It's a great toy; it has a microphone that let's me transmit my voice over the radio (perfect for a Halloween haunted house when the static-mad radio bursts to life with terrifying voice-overs!!!:) works but only up to about a six foot range.  I would like to be in a different room and use the microphone but I need to boost the range considerably - I understand that the FCC has rules about this. Moving forward, I don't know how to do this (at all....). Are there commercial range boosters that I can use? Are there mods that someone can recommend? Are these toys designed to NOT transmit beyond six feet even with mods? I wish I could give more information about the tech specs of the toy but I will have to try to de-solder the metal plate covering the circuit board (plus I don't know what specs to look for yet). Advice appreciated, DAZU

Topic by damianzuch   |  last reply


Could I have some help coming up with a circuit that turns it self off after three momentary button presses?

Hi, I was wondering if I could have some help coming up with a circuit,  Basically me and my friend are modding nerf guns and I thought it would be cool If I could find a way to make the rapid strike fire three darts then stop (or three round bursts XD) Any how the part of the dart gun this in-tales seems to be the little arm that pushes darts into two rotating discs (this is one that uses fly wheels as opposed to a plunger) it works on a motor and gear that pushes it in and out, pushing the trigger activates this.  (I thought it would be a solenoid and that the trigger would put out electricity in bursts, or are those called pulses? any way that's where all this using a momentary switch idea comes from) So if anyone thinks that they can make a circuit using only the power from the trigger and lots of good timing a lesson would be much appreciated :D My Idea seems unnecessarily complicated but it's all I could come up with :D ,Any way the idea for the momentary switch circuit would be put some form of proximity sensor switch near the arm (the one that pushes the dart into the fly wheels). Something like a magnet switch or IR thingy ( I forgot what there called I think magnetic reed switch and Infa red proximity sensor or detector?) the idea after that was that each time the arm passed the sensor it would activate the sensor,  using that and the trigger(if they were both needed to initiate the circuit then releasing the trigger would reset the circuit) the first and second shots would push the dart into the fly wheels and the third would also push a dart into the fly wheel and turn off the circuit(or turn on the circuit activating a spdt relay and switching the link to the motor off) So far I've come up with some ideas using relays but just pressing the button once activated the whole circuit, I've also though of using a capacitor but I don't really know how to use them, if they work by holding X charge that can be filled by pressing a momentary button, that is hooked up to Y amount of power (possibly through a resistor), Z amount of times fills the capacitor stopping the circuit that would work,  though I would have to find a way to discharge it... Thanks for any help if I get any XD , and if posting my current not working circuit designs would help I'll do that, just have to figure out how to draw a circuit...

Question by justomeguy   |  last reply


How long can I run a wifi highspeed modem on an AAA battery using RCA cables? Answered

After seeing a hack where someone used RCA audio cable to hook up an AAA battery (either alkaline or NiMH) that would run a television set for a few minutes, I was wondering if the same could be done with a wifi highspeed modem. Two concerns are whether the simplicity of the materials might allow the battery to damage the modem and how long the battery would power the unit before running out. There is a video of the television set procedure here. https://www.youtube.com/watch?v=0rA-zhTJuFU The primary reason for using a hack like this would be its simplicity, availability and low expense of materials. The purpose would be to be able to power the modem long enough to grab and reply to vital email and other social media messages in short bursts using a wifi device (such as an iPod) in the event of a power outage. This, of course, is dependent upon whether the landline phone/highspeed internet is still accessible during a power outage.   Two other questions that arise is whether connecting two AAA cells in this fashion will increase the length of time the unit can be powered significantly and whether the increase in power would cause damage to the unit without any other materials and equipment.

Question by blodefood   |  last reply


How can a LED be flashed like a strobe, motion activated and installed outside to act as a security light?

This is about home security.  I have posted another security question on single LEDs in the same category. We have a remote house under construction at the end of a cul-de-sac.  My idea was to create some type of motion-activated single flash strobe or LED burst of light.  This light would be installed at the cul-de-sac and the motion sensor could be further away.  I just want to create this big flash so that any one coming around in the wee hours has to decide if they just had their picture taken and do they want to go further.  The strobe would just flash once like a camera flash, not flashing repetitively. So the final product would have to be weather and water proof.  The house is about 200' from the cul-de-sac but there are a number of empty, underground PVC conduits run from the house electrical panel which could be used to run out 120v or low voltage wiring. I've looked everywhere on the net.  The closest I could find were cameras that are made to take flash photos of animals at night and are motion activated. 

Question by GTinWA   |  last reply


Projecting a 'target' dot from the barrel of a toy Sherman tank

I would like to modify a 1:35 scale model tank (it's about 6-7 inches long) so that the barrel projects a dot on the wall and I can determine whether or not 'firing' the tank hits a target.A low-power laser would obviously project the dot, but there are two big problems: the risk of it getting pointed at someone's eye, and the logistics of mounting it in the chassis. Regarding the safety issue, that danger could be lowered by limiting the laser to a 0.1 second burst each time. That's still not safe enough for my tastes, so I don't know whether I'm willing to go that route. And as for the logistics, the turret of the tank will be full of servos, gears, etc., so the laser unit would have to be in the hull of the tank, with the beam channeled to the barrel somehow. Would a length of fiber optics do the trick? Does anyone have other suggestions for channeling the laser?It would be easier from an engineering standpoint to mount an ultra-bright LED in the barrel, but is there any way to focus that into a dot?And finally the target would have to be big enough that there's some chance of actually hitting it - I'm thinking the size of a quarter. I haven't found any laser/visible light receptors that big - any ideas?As an aside, I don't like posting questions without having done some legwork first - I have actually researched this, but haven't found useful info...Thanks!

Question by hawpond   |  last reply


Heavy aerial lift quadcopter?

Hi, I am in a local competition where they are asking for a quadcopter that can lift a box of lead. The box weigh's 25kg. Yes, you read that right 25 kg. The rules state that it must be a quadcopter and it must fit in a meter by meter by meter cube. This limits the prop size to 500mm diameter unless the height of the blades is different so they overlap. I would prefer not to do this. each rotor must lift 7000 grams (payload + weight of quad). I have been using this thrust calculator : http://personal.osi.hu/fuzesisz/strc_eng/ and according to it a 500mm (20") at 4.5" pitch (I just put that as standard) will need to spin at 6000 RPM to produce 7.12 kg of thrust. It also says it will need an 800 Watt motor. I plan on using these motors http://www.hobbyking.com/hobbyking/store/__24433__NTM_Rotor_Drive_450_Series_1700KV_930W.html. They are 930 watts and 1700kv. they run on a 6s lipo. A 6s lipo is 22.2 volts. 22.2 X 1700 = 37,740. 37,740 RPM is the theoretical speed of the motor. I only need 6000 RPM. 37,740 / 6000 = about 6. so the motor has an 8 tooth gear on it and the prop has a 42 tooth gear on it. This makes a roughly 6:1 ratio to slow down and power up the rotor. The motor is 30A constant current, 42A burst. The ESC will be this one http://www.hobbyking.com/hobbyking/store/__25366__Turnigy_Multistar_45_Amp_Multi_rotor_Brushless_ESC_2_6S.html and the battery will be this two of these: http://www.hobbyking.com/hobbyking/store/__9176__Turnigy_5000mAh_6S_20C_Lipo_Pack.html.          When I started writing this I had a question that I answered myself but now I just want to know if you see any faults with this. PS, the winner of the competition is the one who can hover the longest. I also want to do it for as cheap as possible

Question by monty324   |  last reply


Any ideas on an in-ear white noise device to help stutterers/stammerers?

Hi, This is my first post. I don't know much about this kind of tech but am eager to learn.  I want to build a hidden/discrete wireless earpiece which can play a short burst of white noise (1-2 seconds) when a button is pressed (see below for an explanation of why on earth I want to do this). The button would need to be able to trigger the white noise from a range of around 1 metre so that the controller can be kept in my trouser pocket. There are earpieces around which play white noise (to help people sleep in noisy environments) but I want to be able to control whether or not the white noise is playing. I thought about using a wireless earpiece (e.g.) with bluetooth, however it seems like the maximum range for this would be around 40cm. Anyone know of alternatives?  WHY WOULD I WANT TO?! Individuals who stutter/stammer often experience blocks. It's not that you'll hear them repeating sounds or anything - their speech just totally freezes up. For reasons which aren't entirely clear, listening to white noise can help stutters who block to start talking. White noise can be played before trying to speak, disrupting our auditory feedback - resulting in less blocks. Some devices have made use of this, e.g. Edinburgh Masker (http://www.mnsu.edu/comdis/kuster/edinburghmasker.html), but were ugly, bulky and didn't allow you to manually control when the white noise was playing. Other devices, like SpeechEasy make use of Delayed Auditory Feedback (http://en.wikipedia.org/wiki/Electronic_fluency_device#Delayed_auditory_feedback) - which can help some people but is of no use if you aren't already making some kind of noise. Is this impossible?  Many thanks for anyone with ideas on this! Cheers Oli

Topic by ocheadle   |  last reply


Smart amplifier design building blocks help? (making an amp w/ auto-volume adjust by controlling gain with running avg)

I am currently working on a simple headphone audio amp that automatically adjusts volume to my preference, regardless of what video I click on when it is plugged into a computer. I am tired of some video's being so quiet that I have to crank up the volume to overdrive to hear it, while other video's blast out sound and burst my eardrums. And of course when watching photonicinduction videos, he often can be hard to hear his voice at really low volume at like 12 at night when everyone is asleep, but then the sparks and hammers come into the picture, it is often too late to crank the volume back down, and thus makes your ears bleed or waking everyone up in the neighborhood! X-(. (Luckily he has included sound warnings, but I am lazy, and will engineer things that do the hard work of adjusting volume for me! :)   ) In a way, I understand that this will minimize the dynamic range, which I suppose hardcore "audiophiles" will go NUTS over me actually WANTING to do that, but none the less, That is what I want. My design currently is just a simple emitter follower with a NPN and PNP transistor is the class AB operation, and to minimize crossover distortion and give a definite gain, I have negative feedback op amp from the output of the totem pole transistor arrangement back to the inputs that feed the base of the low and high side transistor. (obviously, the transistors by themselves are low impedance output, (CV mode) and high impedance input, and have a gain of like 1.) Sorry, no schematics, but you capable of googling it if you want to see what I am describing. As it is, it works fine. HOWEVER, it does not do the automatic volume, or gain control. That is set in stone by a resistor divider network between the feedback and ground (the basic non inverting amp feedback config.) I do not want a fixed gain. I want a electrically adjustable gain. The thing I plan to use to do the automatic adjustment would be a peak detector on the input, which is probably going to be a simple diode and capacitor with a buffer, and a discharge resistor (or constant current drain) across the capacitor to gradually lower the max output, or possibly an integrating op amp that effectively takes a running average. The output of that needs to control GAIN of the primary amplifier, and I want to be able to control the PID of that thing, maybe by tuning the a LCR circuit, or what have you. It is all nice and analog, just the way I like it! :) If ONLY there was some magical (and common) component that I could control the resistance anywhere in the feedback loop, of with a given voltage w/ respect to ground... I was thinking of like a MOSFET, but I would have to deal with the non linearity of the input vs output impedance, which probably changes with respect to everything from the current flowing through the channel, the voltage relative to ground at the source, the temperature, the alignment of the planet's, what mood god is in, etc etc etc. That is too many factors for an open loop control on to model in discrete stuff! And digital potentiometers are out of the question since, well they are digital, I want an elegant simple solution, and the are $$ and difficult to deal with. They have so many requirements that need to be addressed.  I prefer a elegant discrete transistor circuit, but op amps and other basic building blocks are acceptable, (this thing I want to be built over a weekend with with jellybean parts from by junk bin.) if you happen to know of a specific audio chip that does this for me, please mention it, but I will probably not use it, but maybe analyze the internal circuitry and learn how it works.

Question by -max-   |  last reply