Building Touch Sensors from Scratch?

I am very familiar with velostat and conductive fabric and how to combine them to make textile touch sensors. I would now like to make a touch sensor that's more solid, and made from a firmer resistive substance than velostat. I've been looking up the resistivity/conductivity of different metals here: https://www.thoughtco.com/table-of-electrical-resi.... In theory, as long as one metal (or other material) is more conductive than the other, it should work the same? I've read on silicon and carbon fiber, but I'm not sure if what I'm researching is the solid kind, or the flimsy/squishy/bendy kind.

Topic by LeAnne_K   |  last reply


Changing old touch screen desktop into desktop monitor

So I have this seriously old touch screen desktop from FEC. I've been browsing around and found how to turn laptop LCD screens into monitors using controller boards, finding them by looking up the model number of the screen. I could probably use find the monitor stuff by myself, but when it comes to the touch screen interface, I'm clueless on what to look for. These are the pictures that I took of the boards and model numbers, and I'm assuming I would need something to either connect to the middle board, or something to replace it. I'm willing to take on the task, I just don't know entirely where to go from here as this is the first time I've really dug deep into something like this. The model number and barcodes are from the back of the monitor. At the end of the think white wire there are a ton of connections that go the the old motherboard of the computer. Is there anyone that might be able to give me a hand on what to find? Number on the large center board:............................RG9000PB0880   V1.0                              Below the number there is another number: 0821 Number for the small connector on the far right:.....RG9000PB0260 There's USB1 and AUDIO1 connectors on the large board in the center, and I'm assuming the long board at the bottom is power. mini-update: Could it also be possible to change the touch screen controller, run it into my computer via USB, and then find a controller for the LCD screen?

Topic by JKMan   |  last reply


Electric touch...

Good day!I have a special problem and I am not even sure this is the right place where to ask for help... I have carpet in my office and by walking around I get charged like a battery (electrostatic)...Often I touch someone and I get a shock! (Also the other person, at least I am not the only one...) This is pretty strong some times and annoying most of the times so I thought maybe I can make (or maybe it exists already) a bracelet or a ring or anything with a LED or with any kind of resistance that I could wear and it could "decharge" me. I think I can figure out how to make something fancy but I am not that, lets say, skilled in electronic and I don't know what would actually do the job. Am I the only one with such problem? Does anyone have any idea?

Question by RicKami   |  last reply


Touch Controlled Resistor?

 Hey I want to make a touch pad that if touch in a certain area will change the resistance level and hold this even after not being touched....how would I do this???

Question by rockandjay   |  last reply


Tactiontape - Touch Sensitive Tape for Rapid Prototyping

Hi everyone, Tactiontape is a one-dimensional touch sensor that curves. It's designed to make building interactive physical prototypes easier, even ones with non-planar or complex surface geometry. It functions as a flexible potentiometer and uses a strip of graphite to express a linearly resistive electrical signal, one that corresponds to how far along the tape you've touched. Each sensor is hand-made using materials from an art supply store. Here's a demo: http://www.youtube.com/watch?v=0ggYn70TpZY For purchasing, photos, and more detail: http://www.etsy.com/listing/87989636/tactiontape-curved-touch-sensors-for

Topic by davidholmandotme 


How do I set up my touch screen for Raspberry Pi?

I have a 5 inch touch screen for my Raspberry Pi, and I want to set it up.  It's a resistant touch screen communicating through the GPIO pins.  Here's the screen itself.  I think that all I need to do is do something in the terminal to install it...  I have the driver files.  Here's the link for the driver files.  Please help.

Topic by nancyjohns   |  last reply


can i repair a cracked touch screen?

Its a odd size, so finding a replacement would be difficult, so i was wondering if its possible to repair the crack in the touch layer and make it work again? i doubt its possible but its worth a shot to ask i guess. and if i cant repair a cracked touch screen, can i cut one to te right size? its a pressure sensitive resistive touch screen.

Question by zack247   |  last reply


Capacitive touchscreen - easy to hack via Arduino?

I have successfully hacked a 4-wire resistive touchscreen overlay, via Arduino, but the touch data is very noisy (mechanical not electronic noise). I'm considering a capacitive screen as a solution: are such screens hackable, using just an Arduino and basic circuit-building skills? Brendan

Question by brendanmccloskey   |  last reply


is it best to charge my ipod touch with the lowest amount of amps possible? Answered

Is it best to charge my ipod touch with the lowest amount of amps possible? how many amps should i charge it with? and how do i know how much resistance my resistors need to lower the amps to how much i want them to be? if u can answer one of these questions but not all of them please post ur answer anyway. thanks

Question by MisterHankie   |  last reply


Does anyone know of a cheap touch sensitive button?

Hi I am wanting to replace a keyboards buttons with touch responsive ones, and as I am in capable of any cuircitry work, I wonder if any one here knows a cheap and reliable one that I can buy in the uk, and put in place of the buttons. It can be either capacitive or resistive, although I really dont want to have to punch the characters to get a response. This is my first time posting here, and so I may have messed something up. -James

Question by therimmer96   |  last reply


Tablet PC From Netbook? Answered

Hello Everyone :) I'm new to this community, though I'm not new to DIY projects. I hope somebody can help me out, I need some help with a proposed project of mine.  I have an old Acer Aspire one 751h and it's an 11.6 inch netbook, LED screen, and I'm willing to tear it down to make a windows tablet. I know I need a touch screen kit, but I need help choosing one, I don't mind resistive ( I know it's very hard to find a multi touch 11.6 inch touch screen kit) In fact, I would say I would prefer ressistive as It's cheaper. One more thing, is it possible to use a larger touchscreen on a smaller screen and then calibrate it? as long as it's the same aspect ratio? For the tablet case/ body, inverting the screen and using the original Acer aspire one 751h case isn't hard, but if it's possible to use perspex or a material like that ( no carbon fibre please) I would like a few pointers. I don't mind the tablet having a rectangular feel/ look, as long as it's easy and practical to build. I also have an old  8x6 inch graphics tablet with 1024 levels of sensitivity, is there any way I can use this along with the touchsreen for input? Like behind the screen.  The netbook runs Full HD content and windows 7 fine and has a 16:9 aspect ratio screen, one of the reasons I'm keen on the project . Thanks a lot ! :) 

Question by Nimer11   |  last reply


Has science ever touched on the possibility of using the vacuum of space for electricity?

I have no real knowledge of anything practical or important so forgive me if I sound ignorant . I guess I kind of am. To me it seems like it would be possible to use the constant vacuum of space to create electricity. Like perhaps some type of reverse piston pulling against elastic resistance inside a sealed container therefore creating sound waves which could be harnessed like in a wind belt generator. This cracked out idea occurred to me after seeing the wind belt generators made from hard drive voice coils on here. Until that I didn't even know there was such a thing as a wind belt generator. Again, I'm sorry if this question offends any of the real Einsteins on here who can see why something like that would so obviously NOT work.

Question by owendrake   |  last reply


Where can I get a capacitive touchscreen overlay kit for my laptop?

My laptop is an Asus G72GX (very fast computer) that has a 17.3" screen with 16:9 aspect ratio. I would like to know where I can get capacitive (must be capacitive, resistive is old school and doesn't respond as well) touchscreen overlay kit. I've googled quite a a lot and though I've found some that fit my screen size, but they aren't capacitive. Since my computer runs both Windows 7 and Mac OS X Lion, it also needs to be compatible with Mac OS. -Thank you for you're help

Question by epicnoobpwn   |  last reply


What materials will work best to make a phone sleeve that won't activate a capacitive screen?

I have an old phone that I use just for listening to podcasts. Sometimes my leg will activate the screen while I have it in my pocket, and it will start playing audio, or will take other actions like deleting episodes I haven't listened to! I also sometimes touch the screen when taking it out of my pocket. I want to make a sleeve for it that will keep this from happening. I've tried putting different materials over the screen and tapping them to see if they resist the touch, but they aren't working. So far, I've tried paper and silicone-coated sticker backing paper. I also suspect that cotton cloth won't work, because my leg affects the screen through the fabric of my pocket lining. What other materials should I try?

Question by yoyology   |  last reply


How to operate the Iphone's touchscreen with gloves on.

Now that it's 20 degrees Fahrenheit outside, I normally wear some thick gloves to keep my hands warm. But whenever I need to use my Iphone, I need to slip them off to operate the touchscreen. I heard that the Iphone touchscreen recognizes the electrical resistance of the skin to measure where you're touching it, but I don't know if this is true. I was wondering if there was any method to perhaps simulate the resistance of my skin on the fingertips of my gloves using some substance. The problem is, I don't what to use. Also, if what I heard was wrong, I would appreciate any other suggestions on how to use the touchscreen without taking my gloves off.

Topic by hydrnium.h2   |  last reply


Heating aluminium by kanthal wire? Answered

Hi friends, I want to heat a aluminum rod by kanthal wire. I want to wrap the wire directly only aluminum rod(it means the wire and rod touches). I want to know, is it possible or the contact between these materials make short circuit? Please answer for it.

Question by Gnanak   |  last reply


play the scary maze right here!

The scary maze is a game in which you must guide the dot to the end of the level without touching the wall of the maze. There are 4 levels. Playing the game on full volume helps. http://www.wimp.com/maze/This one below is a scary video, which is not related to the topic. (Couldn't resist adding it!)http://www.youtube.com/watch?v=xEIaPSojGFE&fmt;=18

Topic by BkrevWlevqe   |  last reply


The use of soft circuits in robotics

Sheets of touch sensitive material seem perfect for giving robots a "skin" of sorts. This could easily allow for something along the lines of a robot pet that can tell when it is being petted. It would also be useful for robot grippers, to allow the robot to hold on without applying too much force. With a layer of durable plastic between the circuit and the cloth, the robot could be made water resistant. Not really sure where else to take this, but I think touch sensitive, water proof skin (and also whiskers) would go a long way to making better robot dogs and cats, and probably other kinds of robots.

Topic by MDude 


electric shocker resistance and housing problem, i only have a week or two until the secret santa party

In an attempt to provide a rather "interesting" christmas present as a joke for a colleague i have assembled an remote controlled electronic shocker device ( perfectly safe almost no current at all) by wiring an electric shocker of a design i am familiar with making so that it's power is provided by wires which previously went to the motor of an RC car( i intend to do an instructable on how it was built, if i get it to work!). the arrangement is constructed from the charging circuit of a disposable camera with the capacitor chopped off and replaced by the electrodes that will connect to my receiver's( my colleague) hand,  the AA battery has been replaced with a remote controlled power supply ( same voltage and ampage as an AA battery)system. Enough on what i have built( unless you need more details to help me), here is my problem. I had originally intended to place the shocker in a small box and attach each output high voltage wire to a tin foil half wrapped over half of the box( i would cover the join with a ribbon) the plan was that when someone picked up the box their hand would form a connection across the tin foil halves and therefore their hand would be acting as a resistor in a high voltage circuit so a (very tiny less than 0.25 milliamps) current would pass through it( whether the voltage is applied across the two halves can be controlled by a remote hidden in my pocket so when other people pick up the parcel they get no shock). but i have found that ,although the output wires are at a high enough voltage to shock someone, the resistance of the tin foil means that the remaining voltage to go across the person's hand is not enough to shock them. ALSO the shocker will work across about a centimetre of skin ( like touching both wires with the tip of the same finger) but when the contact points are as far apart as a whole hand( like thumb to last finger) the increased resistance of the hand means that the current is so small that i cannot even feel a tingling when i test it( i had a few (willing volunteer)friends who are working on this with me also test but it could not shock them either). so my problem is that i must either find a much lower resistance form of contacts to coat the halves of the box( i have no means of using expensive materials or ones that need to be heavily worked on before attaching( like metal plates that must be attached to each face of the box)) or a ( very quick and simple, i only have about a half an hour slot of time to do any soldering before the party ) way to boost the voltage ( i was thinking of attaching extra batteries but suspect this would not work and also am unlikely to get an opportunity to do much electronic alteration) or ( most promisingly) must find a way to house some very bulky parts in a housing where i can guarantee that my colleague will touch both electrodes with one finger without suspecting anything until he gets shocked( this needs to be something like the switch on a torch rewired so that the electrodes are on the switch or whatever, or any other gift where the "obvious" thing to do is put a finger on a certain metal point for some reason( preferably when picking the present up)).  I have already addressed any safety concerns so please do not criticise me for this as electric shocks are harmless provided the current is low enough and does not cross the heart.( i have a very low current with both electrodes on the same hand on top of which it only shocks when i press a button on the remote). ALSO please do not suggest i rebuild the whole circuit as i know that the circuit works fine and i do not have time to build it all again or do any serious modifications, THANKS  any answers would be appreciated, THANKS i think i have found  solution,it is really awesome and involves placing a battery in parrallel with the power lead into the shocker from the remote control system. i am not sure why it is working but i suspect some effects similar to capacitors are involved, the really weird thing is it does not shock you when you grab the box but rather when you pull your hand away. incase i find any other problems this thread is still open to suggestions and ideas for other solutions, assuming the system works perfectly after i have soldered my modifications in place( a few days time before i get a chance to use a soldering iron) then i will no longer need any help( providing nothing else goes wrong). thanks for reading all of this.

Question by resistanceisfutileiflessthan1ohm   |  last reply


please help i am trying to create something and its pretty much done but now i need a 12v 10amp battery any safe way?

I am trying to make a simple little circuit to heating coils(salvaged from cigarette lighters from cars) i have it set up so one is negative and one is positive when they touch they heat up but i am unable to get it glowing red hot which for now is good i guess i need to find heat resistant glue and backing so i dont get burned any help would be great 

Question by TaxiS   |  last reply


Force sensetive resistor parallel circuit

I am new to posting questions in forums so please forgive me if I break any rules. I am trying to build a simple parallel circuit to light up 24 LED's with a simple battery pack with 2 AA batteries. I would the lights to come on when a baby touches 1 or more of the 4 Force Resistive Sensors that I will be using. I would appreciate any guidance with building this circuit, any any schematics that would help. I have limited electrical/electronic knowledge. Thanks for your help guys. Cherrick Gordon - The babymaster.

Topic by babymaster   |  last reply


Xbox 360 controller rapid fire ,, testing,, GTA4 Niko Belic twiches

Just joined, because of your post about rapid fire mod.  I am doing it now, but noticed when i use one wire to touch the two sodering points, that niko belic in GTA4 just twiches like he is going to shoot , but never does,,, wondering if I should hold off on soldering because of this.. herd that some people have a problem with new batteries,, iam using new batteries now.. so i have the resister, went out and bought an older matrix controler, d21, just like your pics. so everything is fine,, iam just at the testing faze using one wire to touch both soldering points from your instructions,, but again when i do this in game play not online,, niko belik twiches really fast like he is going to shoot but no bullets come out.. please let me know what you think.. thanks

Question by cujomojo 


I am CRUSHED.... :-(

I had finally gotten my "project" (for the gift exchange) finished, well except for some cosmetic touches to make it look nicer then it did.  I tested it for the last time, and a wire crossed and the speaker when POOF in a puff of smoke. This thing has me so depressed at not being able to finish it and get it sent that I am having troubles just getting back in and tearing it all out to replace the speaker and maybe put in a dampener resister to prevent it from happening again......I AM going to finish this one way or another......just wanted you all to know I am having to deal with a lot lately (my Mom becoming ill and maybe needing full time "residence in a facility" and being the only one left in the family willing to do anything, a whole lot has been dumped into my lap since July. But I DO intend on getting this out somehow, but Tuesday...but I am so sorry for this horribly long delay.

Topic by Goodhart   |  last reply


Slow down cars with trees.

Traffic calming schemes are frequently unpopular with drivers; speed bumps and oddly-placed bollards make life uncomfortable. In Norfolk, England, a new scheme is being presented that slows traffic without even touching the road or obstructing the driver. Two hundred trees have been planted at the boundaries of villages suffering from speeding drivers, and it is the trees that fool drivers into slowing; they are in rows down each side of the road, and as they approach the village, they get slightly closer together, and slightly closer to the road. Seen only in the driver's peripheral vision, the trees give the same subliminal visual clues as increasing speed would, and drivers respond by unconsciously slowing down.  The illusion has slowed traffic by an average of about 3km per hour. The illusion has been used before (rumble strips on the approaches to roundabouts are spaced more and more closely together to create an audible illusion of acceleration), but the more subtle nature of the tree-planting makes it less obvious, and thus harder to resist.  Provisionally seen as a success, more detailed, longer-term results are to be presented to the Department of Transport in the Autumn, with a view to rolling it out on B-roads nationally. The Independent Autoblog

Topic by Kiteman   |  last reply


High-current, electronic sword-fighting, fancy drink pouring, and more @ Makers Local 256 Build Night!

Last weekend, Makers Local held a Build Night event, sponsored by the Instructables team! Armed with Bare Conductive paint pens and a couple of pizzas, we got to making! The first thing we noticed was that the conductive paint pens were only rated to 12VDC. What happens if we took that higher? (More info can be found here)   One of our members though it would be neat to use the conductive paint to create an electronic sword-fighting game! It turned out really well, and his Instructables write-up was really well-made: check it out here! Another member designed a system to dispense soda in style! He wrote up an awesome Instructable about his system here. One final project started as an attempt to make a touch-sensitive piano using the conductive paint, but the piano ended up using aluminum foil due to some inconsistencies in the resistivity of the paint. It still turned out pretty neat! Below are some pictures from the event! Thanks to Instructables and all who attended!

Topic by tylercrumpton   |  last reply


UPDATE: CDROM stepper motor moves up and down now! wiggle problem resolved

To anyone who read my previous post about the CDROM stepper motor wiggling and not moving while being controlled by GRBL and the EasyDriver motor controller, I got that same motor to work. What I did was I completely took off the wiring system of jumpers I had made. I took off the male pins and kept only that. Then, I tinned four new 22 AWG stranded wire (which is a larger gauge than I was using previously), attached the male pins to one end, and soldered the other ends to the motor directly using copious amounts of flux and verifying resistance continuity between all wires and connections. My Take Away: A. The previous gauge wire was too small, B. My splicing of the wire failed miserably, C. The solder pins were in fact touching each other, shorting the system I am guessing that a combo of all three (honestly, mainly B) caused the frustration. Now it is one solid wire from motor to breadboard for each of the four connections. I believe by unsoldering everything and cleaning it up fixed the wiggle jiggle of the CDrom motor. So if you are having these problems with your CDrom motor/ motor controller, check the wiring and the solder joints. I hope this helps anyone having these problems.          

Topic by dankozi713 


How can I make a water level indicator panel for an RV fresh water tank?

I'm rehabbing an RV.    It has a 100 gallon fresh water tank made out of plastic (polyethylene). The tank has four built in sensors on the side of it, 0%, 25%, 50%, 75%, I assume these sensors are just a bolt sticking through the side into the water. How can I make a simple indicator panel which will light up an LED for 25%, 50%, and 75%? I doubt I'd just be able to use the electrical conductivity between the 0% sensor and the other three, as the electrical resistance would be too high to send any usable connection through the water, am I correct? But maybe something based on capacitance?   Anyone know how to build something like that?   My skills are too rusty to think that through. Maybe I could cannibalize the sensor out of one of those touch sensitive table lamps and use it as the basis for my indicator panel? I'd prefer not to use an arduino or pi for this, I need something incredibly simple and robust.   I realize those would do the job but I need the quick and dirty solution. Thanks in advance for your help. EDIT:   Here is a webpage that talks in depth about the standard tank monitors and how to upgrade it with an Arduino.   Unfortunately, this seems incredibly over engineered for this task and I don't have the liberty of spending the time to do this, as I am working with a tight deadline.  But it does discuss the resistor network which was originally used with the sensors on the tank.   Since the original display panel on mine was too damaged to save, I thought it wouldn't be too hard to rig up something simple to replace it.  http://www.thorforums.com/forums/f27/diy-capacitive-tank-sensor-1177-2.html

Question by JimTheSoundman   |  last reply


Modifying Altec Lancings "Life Jacket 2" Waterproof portable speaker.

So I got one of these portable speakers for work. Works great though it could be a touch louder. It lets you charge your phone while either using Bluetooth or direct aux input. Now there's only one problem/annoyance. Every time you power on/off the device and sync to Bluetooth, this voice confirmation plays this audio file that's much longer than it needs to be. "Powering on! Welcome to Altec Lansing" when Bluetooth kicks on "You are now paired! Enjoy!" when you turn off "Powering off!" Anyway, I was already planning on modding it by adding an amplifier to the Line In, since its much louder when a PC is connected vs a phone. I may also add more 18650's but with 15 hour battery life its not necessary. Unless I plan on turning it into a charging hub for all my co-workers phones or something. Anyway, I am here to try to get some help on disabling the voice, its only really a problem because on max volume the voice is WAYY too loud and usually startles people. Here's a review video that shows all the features. Amazingly I can't find a Youtube video of the Voice Confirmation. Here's the useless manual. Manual I Already emailed Altec Lansing to see if there's anyway to disable the voice. I have several images for you to see. I can grab more if necessary. Alternatively, would I be able to just replace the entire board with another one? Such as, an amplifier, USB charger, 18650 charger, and some hacked up Bluetooth headset (with no voice-confirmation) I ask because I rather like the case for its shock resistance capability, and the control buttons are removable so adding new controls and switches would be easy.

Topic by Crusty-Bobcat   |  last reply


Throwies reimagined - Really I did tried :) :| :/

Seeing other forms of making interactive throwies, eg using microchips impresses me.However i think it is important that we try parts of the B.E.A.M philosophyhttp://en.wikipedia.org/wiki/BEAM_roboticsNamely keeping things simple, and avoiding the use of microprocessor.The component of a interactive throwie is that it has1. Power storage2. Trigger3. Circuit4. LED5. (optional) Power collection of radiant energy.I like to see more suggestion on ways we can address each issues.But to kick start the issue, can you see if my idea is feasible.essentially for my prototype not-yet throwie, I used a circuit from http://unconventional-airsoft.com/2003/11/16/momentary-fan-switch/#more-21to create a throwie that on sensing motion, doesn't flicker but turns on for a while.By ensuring that i use few and simple componants, i hope to keep cost per throwing down.Unfortunately my problem is that using a resistor to keep the capacitor from draining too fast from the base, actually decreases the voltage drop to an unacceptable level at the led.On my end it is unsolvable for the moment. Maybe you can work out how to make a cheap throwie, that can still do these functions or more.Any ideas how to solve this?Other Ideas for throwies1.Open and attach a switch to a barometer, to have a air presser passive trigger.2. A leave shaped pad with two conductors that do not touch, to act as rain sensors. (Resistance increase when leaf dries)3. Is sensitive to infrared radiation from side, so that the throwie is trigger-able by other activated throwies. (As well infrared devices)4. Has a short loop of coil to recharged capacitors, by outside induction.5. If activated rarely, uses a tiny single solar cell to charge capacitor.6. Has a hook to be easily collected for recycling. (Using a simple loop of wire on a pole [Like a dog catcher pole] )7. A single thermistors in series with led.8. A tricolour LED, and a Two light resistor. One LDR acts to sense if it is day an night, if night a low power light is activated. Only when an object strays near, and reflect light into another LDR, does the throwie get triggered at all.9. A throwie triggered by vibration.10. A throwie that responds to radio waves.

Topic by akimbo m   |  last reply


Can anyone explain RMS vs average? (particularly the math portion, and the intuition)? Answered

My current understanding of RMS (Root Mean Square) is that it is the equivalent AC voltage/current/power necessary to drive a resistive load the same around as the DC voltage/current/power counterpart. However, I am a bit confused about the math involved that can apply to all waveform. I know the conversation factor for sine waves is 1/ sqrt(2), and that the conversion factor for square waves is 1:1 (no difference) On my graphing calculator, if I take the square root of the definite integral (from 0 to pi, integrating the x ) of the sin(x)^2, then divide that by the period, pi, I get the correct answer. However, what is the purpose of the squaring, then square-rooting? is it purely to perform a absolute value mathematically? If so, then I should be able to simply integrate the absolute value of the sine, and divide the result the the period the integration was performed over. If it period it was performed over was 0-pi, then there is no need to even take the absolute value! But this method returnees 0.636619... not 0.707106... Intuitively, it makes much more sense to me to somehow take the mean average of the continues |sin(x)| function. I know this can be done with desecrate numbers (a sequence, perhaps) and by taking the sum of them, and dividing it by the number of 'elements.' (series's, anyone?). I would expect this average is what determined the average power used by a load. EDIT: Wikipedia states that "The true RMS value is actually proportional to the square-root of the average of the square of the curve, and not to the average of the absolute value of the curve." So it appears I have just proven this. But Why???? What is so special about the squaring and rooting??? Please don't bombard me with heavy math, as I am not familiar with calculus, and have barely passed pre-calculus (The class was supposed to touch upon series and sequences, and integrals, derivatives, limits, etc. but due to show days and delays, the class only covered trigonometry --the bare essentials--). I do not yet fully understand single-variable integrals, let alone multi-variable calculus. I really just want a better intuition of RMS. More than likely, there is probably some confusion I have about integrals in general, and how to calculate them on-paper.

Question by -max-   |  last reply


Electric Go Kart with Graphene supercapacitor. Random Questions on electronics, control, and possible problems.

I have a project in mind that i am trying to start on and it all has to be done as cheap as possible (ACAP). The project idea is that after my graphene in finished and I make the capacitors I will construct the battery and group the many cells in series and parallels until I have either 36 or 48 volts and a lot of amp-hours or at least enough to drive the kart with unrestricted speed for AT LEAST 10-15 minutes. The big question I have is whether i can treat these, essentially fast charging batteries, as batteries or if I must use different methods to control power and connect to the motor.  Then I also don't know how exactly i am going to control the motor or even what type of motor to use and where to obtain it. I was thinking i could use some industrial PMDC motor and I would like to control it using a PWM and use a plate that a contact touches that would slide up and down the plate to make the contact closer and farther away from the end on which a cable would be attached so it varies the amount of resistance to make a potentiometer. The closed throttle would just be a button that the pedal pushes to disconnect the power to the potentiometer at another point in the wiring. If that actually works then how would I make or where would I buy something that could actually use that and be able to handle thousands of watts (like 10,000W @36-48volts minimum).  My other throttle idea was that i could just have the pedal activate multiple solenoids so that there is like 5 stages of power activated by the solenoids. I have heard that problems with this is that when the first battery runs out you have to charge it otherwise it will be destroyed, though i am not sure if this will affect the graphene supercapacitors. If anyone know anything about graphene in applications please let me know because that would be way easier. The last thing is that since the graphene will be made on disks by laser scribing them could i just make the cells the shape of CD disks and then put the in one of those disk holders and then wire those to each other in series until i have the desired voltage and then in parallels until I run out??? If anyone has made graphene cells and used them please tell me where u obtained the Graphene oxide and how you made the graphene and cells and etc.

Question by hopekiller30   |  last reply


Help sought for DIY 12V for 120V Blender Boat Motor

Howdy, I’m hoping someone could give me a hand with jerry rigging a DIY trolling motor battery for a small boat (not a toy, but made out of many many water bottles, pvc, etc.) that will not get too much use. I need it to be very inexpensive and reasonably light. 10 D cells in a PVC pipe would be great. 20 would not be too bad. I am pretty much electrically illiterate. Here is what I have so far. I have an immersion blender … one of those things that Emeril Lagasse calls “boat motors”. I can attach a drive shaft and propeller to it. Because it is designed for being in liquids with more resistance than water (though with a smaller prop/blade), I think it will have sufficient torque to get some push. I will not know if it is enough until I give it a try, but I do know that weed wackers can be so converted and I don’t think they have much torque. The part I am stuck on is hooking it up to batteries. It is a 120V plug in device. I have a small 75 Watt inverter. I can plug the blender into the inverter and that into a car lighter and it runs well. I have hope! I understand that I should have 120 Watt inverter, but 75 is what I have. I have an accessory car lighter outlet to plug the inverter into. It has a red line with a fuse box mid way and a black line, identified as a ground line with a loop at the end. The directions say to screw that loop into the frame of a car and connect the red to the hot battery line. But as I am not using a car that is not of much help. I tried stringing 10 AA batteries together end to end, temporarily held snug with duct tape, and connect it to the inverter with the accessory lighter plug outlet, but I did not have any luck. The motor did not spin and the inverter power light did not come on. I used electrical tape to connect the red to the positive end of the string and tried taping the black to the negative and also to a knife to ground. I tried AA as I know those will get used one way or another. I did not want to invest in D’s until knew it would work. As I understand it, D’s will last longer. (I am not interested in re-charging). Since then, I came across a few bits of info on another site. One thread mentioned using a spring from, say a flash light, at the negative end and a bolt at the other. Another said that PVC was great for grounding. Some useful bits of info are that in addition to the 120V, the motor runs at 1.0 Amps. I do not know if the 60 hertz is relevant. Does any one have any ideas about how to do something this? Do I just need to replace the fuse and try again with D’s? How do I connect the lines? Wrap the red around a bolt through a capped pvc tube and tape the ground to the side of the tube, with a spring in the other capped end touching the negative end? Do I need two 10 series in parallel? I can stack batteries end to end, but how do I connect parallels, especially without soldering? I do not want to use a 12 volt car or marine battery. This motor is not going to get enough use to justify the cost of such a battery and charger and I do not what to deal with the weight. If I can get 10-15 minutes of power from a stack of D-cells (hopefully more time), I would call that a success as this is a learning experience as much as anything. An hour would be much better. Thanks in advance for any help.

Topic by Wolfsire   |  last reply


A complete roleplaying game in one post

I can't post this as an Instructable, because it's not my game at all.  It surfaced in the sorting out of my lab as my school closed. My original copy of the game was a page in Games and Puzzles magazine, but this is my own re-type of it, which I had to re-type again because the first digital copy was lost during one PC upgrade or another. The document gives me permission to pass it on (even though it pre-dates the Creative Commons movement), but I have emailed the author to let him know I'm posting it anyway.  I've not had a reply, but the page I found his address on had not been updated since 2009. UPDATE: Frank has been in touch, is happy for the game to be published like this, and is even going to send me copies of v2 if he ever finds them. FURTHER UPDATE: Frank has sent me a scan of the v2 rules, which I have added as the first image below. I thought older members might like to be reminded of their youth, and younger members sometimes need reminding that roleplaying games didn't always need a computer with a high-speed internet connection Here is the text, and I have attached a tidier-looking PDF of the same text: --------------------------------------------------------------------------------------------------------- S.I.M.P.L.E. by Frank Carver Shared Imagination Multi Player Leisure Experience Have you ever been sitting around with a few friends and wanted to play a game – but hadn’t brought the rule books, supplements, charts & tables, character sheets, funny dice, metal figures etc? Here is the answer: a game simple enough to fit on one sheet of paper, and easy enough to remember & explain, even if you haven’t got that! ABOUT SIMPLE SIMPLE is a roleplaying game (RPG), in which each player controls the actions of a single character in an adventure. An adventure takes place in an imaginary world, which may be very different from the real world. Sometimes it’s outer space, the far future, wild west or fantasy. The background from any book, film, TV show may be used, or one from your own imagination. The adventure is usually organised by one player acting as Game Master (GM), who knows about the setting and provides things for the characters to do – problems to solve, enemies to defeat, victims to be rescued, riches to be gained ... anything the other players might enjoy. Problems are solved by thinking them through, talking to the other players and the GM, and rolling dice to see if your plan works. Details of each character are recorded on a character sheet, which develops from game to game. Travel the Universe without ever leaving your chair! TO PLAY You need at least two players (more than 5 or 6 is hard work), a copy of this sheet, at least one normal 6-sided die, a pen or pencil (an eraser is handy), some paper to write on and your imagination. THE SIMPLE CHARACTER Each SIMPLE character is described by three things – Body, Mind and Abilities. Body is a single number showing how strong and tough the character is. Mind is also a number, showing how clever and aware the character is. Abilities are things the character is good at. Each Ability has a description, and a number which shows how much better than average the character is. If your character is just average at something, it doesn’t go on their Ability list. Each character starts with 10 character points, which may be put into Body, Mind and Ability. For each point put into Body or Mind, the number goes up by one. For each half point put into Ability, the number goes up by one. Abilities may be anything that suits the setting. The GM and other players must agree with them. For example: running, science, driving, casting spells, seeing in the dark... EXAMPLE CHARACTER SHEET Name: Gus Goodguy Player: Frank Body: 5 Mind: 3 Abilities: Gunfight 2, ride horse 1, drink whisky 1 Description: A gunfighter in the Old West. Rides tall in the saddle, tips his white 10-gallon hat to ladies, calls men “Pardner”, travels the dusty plains looking for bandits to catch or farmers to rescue. Likes his whisky, and wil never resist a call to a shoot-out. USING THE NUMBERS IN AN ADVENTURE To see if a character succeeds at a task, the GM decides on the difficulty (5=easy, 8=average, 11=hard, 14=very hard and so on) and whether it is a physical (Body) task or a mental (Mind) task. The player then rolls a die and adds the character’s Body or Mind and any matching Abilities. A 6 means roll again and add the result. If the player’s total is better than the GM’s target, then the character has succeeded. The difference between the two numbers gives how well it was done. Gus Goodguy has Body 5 and Gunfight 2. To shoot Bill Badguy is an average (8) Body task. Gus rolls a 3, plus his body of 5, plus his gunfighting 2, making a total of 10 – succeeded by 2! Bill has been shot, and until his wound is treated his body is reduced by 1 point. If his Body falls to 1 he is unconscious, if it reaches 0 he is dead! At the end of a game, the GM may award up to one point to good players to spend on their characters. DOING EVERYTHING ELSE Most problems should be decided by the GM and common sense. Some useful hints, though: when time is important, like in a fight, do things in one-second rounds, with the character with the highest Body going first. A character can run Body (plus running Ability) metres per second. An “average” person has 4 Body and 4 MNind with no extra Abilities. If you need some enemies in a hurry, roll some dice onto the table – use the numbers on top as their Body score, and turn the die down one when they are injured. If you like this game, please copy it, give it to your friends, take it to conventions etc If you like it a lot, why not write to Frank Carver at: The Albion Guard Games Club, 62 Tomline Road, Ipswich, IP3 8DB, United Kingdom. This document is copyright Frank K Carver, 1992. Permission granted to copy and distribute this document, provided that only the complete document (including this provision) is copied and/or distributed. Enjoy!

Topic by Kiteman   |  last reply


Hydrophobic music, dubstep windchimes, Smash Smash Revolution and etc @ Knox Makers Build Night w/ MaKey MaKey!

Wow, what a month at Knox Makers! We were absolutely invaded by MaKey MaKeys at our hackerspace all throughout January. To start us off, we released a freebie project a little early to help out members and guests get some ideas, to drum up local support for our events, and to offer a fun + easy starter project for the other spaces participating: Oversized Music Chest This ended up getting featured in Electronics! It leaves a lot of room to add extra components and tote the MaKey MaKey around, and we turned ours into a musical advertisement for our first Build Night, a mystery hack night about music. Mystery Hack Night: Music! What a blast! Talk about a weird time.. One family brought a theremin and a circuit bending kit for kids; another group brought an amp and speakers, a suitcase of effect pedals and circuit bent instruments, and a 4 channel mixer; we had a random component table for open hacking; an acoustic and broken ukulele was converted into an electronic instrument; we had painters painting music instrument for the MaKey MaKey with conductive paint; there was a table with our hydrophobic drum pad, bananas, an eggplant, flowers, and a grappling hook all controlling a set of browser based drums through the MaKey MaKey; we had members hooking up tactile buttons and levers to MaKey MaKeys; and we closed with the weirdest jam session this side of Alpha Centauri with all the things playing all the sounds at the same time. Mystery Hack Night: Video Game Controllers! This was a fun night, and we had a few new people show up. We tinkered with a platformer adventure game called Fancy Pants Adventure, where we assigned each person one button. At one point, the whole table was controlling the game's protagonist. Somehow, we made it pretty far into the game, considering. A few people commented that this type of exercise seemed like a really useful team building exercise, so we might look at creating some tutorials with this in mind. We also had individuals and small groups testing out their own inventions and games, again revisiting concepts like conductive ink or simple conductive objects. A two person team tinkered around with some simple fighting games that only use one button for each player, there were people playing Tetris and other games with their inventions, and we again offered a random hack table with an assortment of items and components to rummage through. MaKey MaKey Build Night I: When MaKeys Attack.. We had a nice turnout for this event. This was an introduction to the basic concept behind MaKey MaKey, how to remap the beta v1.2 boards using the web remapper, different applications that make a MaKey MaKey naturally awesome to use, and a few sample projects. We opened up the floor to open hacking, and that day our Adafruit group buy had just come in. We were able to add to the random hack table some awesome components, such as: male/male and female/female jumper wires, various diffused LEDs, slow and fast cycling LEDs, conductive thread, flat LED panels, sewable LEDs, tactile buttons, and other items. We wrapped up and one of our newest members stayed late to craft a thin copper wire into a flat copper instrument using a mallet. He ended up using a breadboard with the MaKey MaKey and Wolfram software to write his own music program. As with our other Build Night events this month, we also had people working on side projects in the background which added to the creative energy of the room. For this event, one of our members tested out a Gocupi that managed to draw Rear Admiral Grace Hopper and Albert Einstein on the whiteboard in dry erase marker using continuous lines. MaKey MaKey Build Night II: Big Projects! We had a decent turnout for this event, but mostly the attendees were there for their own big projects unrelated to MaKey MaKey. We got a few MaKey MaKey projects in around good company, though. We had members working on a large geodesic Airolite boat, someone showed up to work on their 3D printer and print out their first scale model of a scanned person, our Facilities Director was able to get some critical inventory done, a couple members mounted new shelves that had been donated that day, and one member's daughter wanted to play around with hydrophobics. We also were able to get electronic musical wind chimes made that work very nicely with the MaKey MaKey, and the same member who tinkered with Wolfram software at the prior event made more progress on some of his own MaKey MaKey ideas. MaKey MaKey Build Night III: Advanced Reprogramming! This was one of the build nights I was most excited about, and we had a nice turnout. We walked members through reprogramming the older MaKey MaKeys using the MaKey MaKey sketch for Arduino IDE. We bested Windows and its infernal resistance to unsigned 3rd party drivers, and we advanced onward. We looked at basic reprogramming of the settings.h key bindings, and we also looked at other Arduino programming such as delay, Keyboard.print, Keyboard.press, Keyboard.release, and some other concepts. A father team duo that are also involved in a local high school robotics club showed up and schooled us a little on Arduino with some tricks they had up their sleeves, another father son duo showed up to experience the MaKey MaKey for the first time together and it seemed to blow their minds, and we talked about the new web remapping tool for the beta v1.2 boards. Mad Science Bingo For one of our educational outreach events, we attended hijacked bingo night at a local senior citizen community center. We let everyone have their bingo fun without interruption, but as bingo concluded we invaded with a MaKey MaKey, our hydrophobic drum pad, fruits and veggies, and some flowers. The senior citizens loved it and have invited us back. At one point, we had three participants record themselves singing into a Scratch program that we mapped to the flowers. The room erupted with laughter when the community center manager went to touch the flowers and they sang at her in her patrons' voices. She even lent her voice to be recorded, which sent the room into mad howls. We also made a chain of about dozen people between ground and the triggers. We didn't really invent anything unique here, but it was a fun bonus event for the community center patrons. We ended up tinkering around a little with hydrophobics and electronics. So far after all our events, we ended up with a few more Build Night projects: Hydrophobic Drum Pad (featured in Science and then Homepaged!) annoy friends with this party game: Wonky Pong Smash Smash Revolution ... black acrylic, conductive paint, and conductive thread Electronic Windchimes sewable Cardboard Feet DDR (featured in Video Games!) We've also set out our MaKey MaKey kits for space use now that our January Build Nights are over with. We have a few members with projects they are still working on at the space, a few projects that are still being documented to upload to Instructables, and a few people batting around their own ideas. If we come up with anything else, we'll be sure and update. A couple "lessons learned" here: Random hack tables are awesome. But.. if they are too chaotic and without the right presentation, these can be intimidating to beginners that may want more direction. Multiple Build Nights rule! But.. it is probably best not to hijack every Saturday of a shared workspace like a hackerspace. This could have been orchestrated a little better (my fault). Overall, this was a blast to participate in. Thanks to Joylabz and Instructables! PS.. with two features and one homepage, that gave us 1 and a half years of Pro. One got used, but we're giving away the remaining year of Pro and 3 months of Pro. The bounty: quick connect projects for MaKey MaKey. Ends 3/1 EST. You know what to do..

Topic by smalltortoise 


Mono pole / single pole magnets!?

I made a quite intersting discovery today.The use of mixed orientations for a stronger or more directed field on one side and a much weaker on the other side of a magnet is nothing new. But if you check modern wind turbines or even just any old hard drive you find "chokes". I talked about shielding before but combining shielding a choking provides again another level of manipulation.If you ask anyone who claims to know magentic field or sience in general then you right away hear: There is no such thing as magnet with just a single pole!Like a battery one pole can't exist without the other!Keep going and your conversation parten either get angry or declares you a nut case.Also said before: The laws of nature and physics are not set in stone or complete for that matter!We only use what we know, or to be precise what we told to take as facts.A magnet with just one pole is impossible to manufacture, if you only think like making the magnet like any other magnet.Even cutting it in half will only give you two normal magnets again.Why is that so?How are magnets made is what you need to know.No matter the material they start as a blank and during the final processing an intense electromagnetic field is used to "prime" them.Like you would do on a screwdriver the material then keeps the "charge" and becomes magnetic.And this process requires a certain orientation.Imagine a big hydraulic press to make the magnet with some super strong electromagnets right beside the forms.Explains why you won't find a block magnet with the poles on opposing corners - the form is not designed to be rotated ;)Ferrite magnets can often be machined.If you mark the field direction of a block then you could just cut it into the shape you need.Like a half moon, triangle, pyramid...The orientation does not change, so you need to create the cuts so your required orientation matches the orignal block.Creates a lot of waste, is messy and often the magnets shatter.Still not possible to create a mono pole ;)But it allows for a great deal of field manipulations.For example a thick north and a thin south pole would show very different field strengths at the poles.How to create a mono or single pole magnet then??If you think outside modern science restraints it is suprisingly easy!You see, unlike a battery the magnet does not care if the "current" flows back to its own pole or a pole from a different magnet.In a hard drive the choked magnets have a field strength between them that is not just twice as much as th one from a single magnet.The field between the magnets is very stable too!No matter where you measure it is the same.Place two magnets in the same configuration with the choke and all you get between them is a mess.To understand the reality with magnets I need to explain a bit more though:If it does not matter from where to where the field lines go the it becomes obvious that you can guide them.Horse shoe magnets of the old kind where just two steel bars with a block magnet between them!Take a compass and check from what distance your magnet will start to affect the orientation.Now take two iron bars, rods, block or similar of about twice that length.Place the compass between one end and the magnet between the other end.Even with a little gap your compass will still move!You just extended the length of the field lines and directed them somewhere else as it also works with odd shapes.We know know and confirmed how choking works and as shielding is basically the same thing but for a different purpose you might get an idea where I am heading already.A "potted" magnet, like what you find in a speaker or as a hook magnet utilises two destinct features.a) A ring magnet is used.b) The field lines are directed to a specific area.One has them directed into a gap for a coil like in a wind turbine, the other to the surface to massively increase the field strenght in that area.If you take either apart you will notice the magnet just by itself is considerably weaker.Removing a pole from a magnet...If you paid attention so far and have a few magnets around then you already developed a feeling for the difference.Lets crank it up a notch, shall we?Make this experiment:Take two identical magnets and a soft steel bar or similar of lesser thickness than the magnets.Usually around 2-3mm for smaller N52 Neodymiums will do.If you dare make the steel the same size as the magnets.Now place one magnet on the steel and use the other to observe the difference in feel.There won't be much and both poles should still fell like before only that the field is now slightly longer.Trying to get two magnets to touch at the same pole is really hard, but see what happens if you add the other magnet on the other side of the steel...Despite having the same pole on the steel they won't repel and stick to the steel.Checking the field now with a magnet provides a very different feel!It is like having a magnet with a split pole where the opposing pole now is in the center.Impossible I know but you have it in your hand, so deal with the explanation yourself ;)And if that is so damn easy then how hard can it be to actually remove one pole fully?Design of the impossible magnet...If you want the south pole only then it would be the entire surface of your impossible magnet.That means you either need to make sacrifices or get creative for the next steps.Easiest from my experiments is to sacrifice like all scientists do and allow for some minor gaps.I won't give any dimension or step by step instructions.Think 3D and use your imagination.Our impossible magnet starts from the center.All magnets used should provide the same field strenght!To be precise it means no matter their grade, the the "force" of the magnets should be as close to identical as possible even if the size is different.You can use stacks or different types/grades...The center is a square block of soft steel, or iron as pure as possible - it needs to have a low "resistance" if you compare them to batteries and to avoid confusing terms.On this "dice" you place one magnet on each face, preferably of identical size to the block.So, for a 10x10mm block you use 10x10mm magnets -simple isn't it.All magnets are place with the same pole onto the block!In out example to get the south pole outside you would use the north pole.Now use six bigger magnet blocks for another layer.This time they are placed in attraction mode, meaning you let them stick together naturally.The resulting magnet will be far from perfect but you will have a hard time finding a strong attraction to the soth pole of a magnet if you move it around your cube.If you check the geometry you will now see how 45° degree angles and matching sizes for the blocks would be beneficial.Using ferrite magnets you can machine them to the desired size and use a thin aluminium or breass frame to hold the outside properly together, like edging on a fancy tranport box or chest.Check the magnet now and try to find anything else but a destict south pole on all faces and corners.No more nother pole....Does that mean it really is a mono or single pole magnet?Since modern science does not even consider a construction like this to be worth testing you already know the anser.For those working on a different level with magnets it will be a true single pole magnet.For the rest it will just be another fake.As by science a permanent magnet is defined to have two poles and to have field lines going from one pole to the other.All modern machines using them operate on this principle and "fact".But if I would give you a block of steel that has a core of lets say brass and a suffien wall thickness...Then this block would appear to be a steel block and nothing else.Modern science fails to see a magnet any other than a battery!If the "current" does not need to go back to same pole and there is no need for the field lines to go back to the outside pole then it is a single ple magnet like the faked box is a steel box.The physical outcome or in our case magnetic field is what defines it!The contra...All good has some bad, magnets are no different.Purely scientific viewed it would be impossible to create a gap free magnet like I described.And because never all field lines will take the shortcut there will still be a small amount of "north pole" to be found on the outside.But if that is in the range of about 1% of the field strength of the magnet then I say it can be neglected for almost all real life uses of such a magnet.Like the Halbach Array it is just a neat way of manipulating and if you like bending the known interpretation of our scientific understanding.Possible uses for these magnets exclude convention designs and for this reason alone anything you create with them will be the target of scepticism to say it nice.Ok then, what real life uses could there be for something we never needed?The question is the answer, as the impossible magnet is the solution.Ever watched these shopping shows in the night program?"It solves problems you didn't even know you might get..."Means that if you ever get the ide that your project requires a single pole magnet then you know how to make one ;)All I can up with would go against common scientific understanding and teachings, so I will spare you with my use cases ;)And what is missing here to actually make it work?Quite a lot as you might have noticed in your experiments if you use really good test equippment.Not so much however if you consider what I said about shielding and choking ;)Provide a path of far less resistance and shield the rest that still bothers you.I am not providing a ready to go model here that you can buy, someone else will do that if they see a financial gain it.My gain is provide a new understanding of things we forgot by giving your brain things to work with and develop.You might still say in the end that my way (or your results) are not good enough in some way.But then please also consider how many other people or documents you might be able to find that would have provided you with this information.Free energy is only a myth for as along as we allow ourselfs to only trust what modern science allows us to have.Allow the old knowledge in and every now and then simple ignore what you know and things become possible sooner than you might think.Wind and water were used as a source of free energy since the dawn of mankind.Our first motorised boats used the same "wheels" we already trusted to be driven by water to power a mill, saw or similar.And after we learned about motors we also found a way to make wind - by reversing our trusted wind mills into a fan.Instead of using the free energy to generate power for us we evolved to use create wind and propulsion by providing power to drive the same thin in reverse.Using the sun for power other by using a mirror was seen as witchcraft throughout history, then we got solar cells...Same for heat in the form of peltier elements and other things...Why then should magnets be any different??Just "Because it is so!" did not work for wind, water and solar, not even for heat....All it takes is a little notch in the right direction to change the way we think about magnets.We have no problem using electromagnets to make a motor spin.We have no problem using magnetic field of any kind to drive motors or generate electricity.We even fail to have a problem by manipulation electromagnetic fields for that purpose.But we struggle like an ant in sand hole to reach the surface again to see what is outside our trap before something grabs us from behind when it comes to permanent magnets.Even worse if you dare to claim your magnetic machine delivers a higher output energy than what you use to make it run.And wasn't it exactly the same ignorance and manifested "knowledge" that got revised so many times throughout history already?Again: Why should magnets or their understanding of interaction be any different?If you follow the above with just matching magnets and the core cube then the result will be at least very surprising to you.Allow this surprise to be an inspiration to improve instead of seeing as a proof of failure ;)And if you made it then please post about it here.Let me know what disappointed you with the outcome.Let me know what really got you wondering.Let me know if you found a suffiently strong north pole to rival the impossible southpole! ;)Start sharing, make other people wonder and make them share it to, let us go viral!The first to post a conclusive Youtube video with results is certain to get a lot, lot, lot attention....

Topic by Downunder35m