I need some help in this homework. Foil length of strain gauge is L Resistance of strain gauge is R Equation is deltaR/R=0.485(deltaL/L) the strain gauge is given a strain of X%. The question says to calculate the change in resistance on the strain gauge. My problem is that i don't understand the X% strain. I'm not asking for answer, just want to know what the X% strain means

Question by ARJOON 7 years ago  |  last reply 7 years ago

### pressure gauge

HelloI have a heat press that has no pressure gauge. I am trying to figure a way to add a manual one.So when I close the upper platen to the bottom I can tell how much pressure is being exterted on to a substrate that I am pressing. If a way coudl be found to do it while being able to withstand 400+ degrees F that be great but if not doing it cold shouldn't matter.Thickness would have to be less than a inch.I was thinking a air bulb like on a blood pressure cuff and some type of gauge but not sure about that.Anyone got any good ideas.THanksMark

Topic by freebird1963 9 years ago

### temperature gauge ?

Where  can I get a replacement spring type outdoor temperature gauge?

Question by ssivels 2 years ago  |  last reply 2 years ago

### Trip Gauge

Hey, I was just wondering if anyone knew where I could get an inexpensive (used is ok) trip gauge to tell me real time MPG in my car. I didn't see much on ebay, and am not interested in spending \$169 on a new one. I'm not sure the year of my Ford Taurus, but I can check tomorrow. Thanks!

Topic by Weissensteinburg 11 years ago

### Laser Height Gauge

Hello, I wanted to know if there was a way to build a laser height (measurement) gauge that can measure to .001 or .0001?

Topic by vash399 1 year ago  |  last reply 1 year ago

Anyone interested?

Topic by GaryS25 3 years ago  |  last reply 3 years ago

### Trying to locate

I am looking for a Center zeroed meter (just the analog gauge, not a complete meter), or at least an idea on what I might find one....so that my dumpster diving become more precise :-) like the one contained herein:

Topic by Goodhart 10 years ago  |  last reply 10 years ago

### Free Guitar Neck Radius Gauge

At times we need to know the radius of our guitar neck and this site has a free download template with all the options on, I have made a couple before and they are easy and acurate. Go here   I used an empty plastic ice cream tub to transfer gauge onto. http://www.pickguardian.com/pickguardian/Images/ Pickguardian%20Neck%20Radius%20Gauges.pdf

Topic by fenderphil 8 years ago

### Electronic water level gauge for well

I have a 32m deep, 95cm diameter well, that is covered with two heavy concrete covers. The water depth is about 20m down from the surface. I cannot easily access the well to sound the depth or visually check the water level. I would like to build an electronic water level gauge that will tell me the amount of water in the well. I can then regulate watering accordingly. It was suggested to me that I use a washing machine pressure transducer but I have no idea of the circuit required. A refined solution would send data to my PC !!!! I have 240v AC supply to the well pump. Any ideas? Steve

Topic by SteveG31530 10 years ago

### Auto body help

I need some help here and I hope that there is someone that can answer this question. I have a 2003 Toyota Tacoma and I want to add some bigger fender flairs on the truck, I want to use what are called pop rivet nuts. The pop rivet nuts are inserted just like a pop rivet but it has a nut on the back of it so that you can use a small bolt. The screws that came with the fender flairs are called self tapping screws and they seem to wallow out after time. I need to know what the thickness of a typical fender is so that I can order the right pop rivet nuts. The pop rivet nuts only come in sizes for gauge metal. Does anyone know what gauge a finder is so that I can order the right pop rivet nuts. Thanks for any input.

Topic by fishhunter1957 10 years ago  |  last reply 10 years ago

### Instant MPG gauge for OBDII

This is very simple. I want to know how to make a simple (& cheap) instant MPG meter for a vehicle fitted with OBDII (i.e. most recent vehicles) that will plug into the OBDII port.

Topic by monkey-boy 10 years ago  |  last reply 9 years ago

### electromagnet gauge makes buzzing noises?

Hi, i've been working on a project that involves reusing the electromagnetic needles commonly used in 90's era ford gauges. i can get it to work fine, but it seems to cause a buzzing noise as it is doing the work. there are three pins, ground, power, and signal. right now i just have it working off of 5v. when i have it going, and you hold the needle with your finger, you can feel it vibrating. i'm using an arduino nano, a npn transistor, and the gauge with a PWM output. do i just need to put a capacitor in? or how do i keep it from buzzing like it does? its not a loud buzz, but you'd notice it if you were in a quiet room.

Question by zack247 5 years ago  |  last reply 5 years ago

### How to make a pressure gauge with a cut off valve for an air filled seat cushion? Gauge suppliers?

I need a pressure gauge to take the guesswork out of filling a seat cushion to the proper level.  The pump is a push/pull pump that inflates on either stroke and has a rubber connector that just slips over the fill valve for the cushion that unscrews.  It's a matter of comfort/stability/safety, where under/over inflation can impact the safety. currently it is done by "how does it feel" and physically feeling the firmness.  Both of them are subjective and can be wrong.  This is the reason for the gauge which would only vary in conjunction with the weight of the person sitting on it and air temp(altitude on rare instances). Thanks, Erich

Question by houdini65 9 years ago  |  last reply 9 years ago

### using a strain gauge to make a load sensing pedal

Guys, I want to use a strain gauge as a load cell in a driving game, where the brake padal is force sensitive not movement sensitive. Currently the pedal is set up with a rotary potentiometer which has three connections and is basically the same as a PC joystick, complete with the circuit board. The strain gauge is one of the resistive film type with two connections, and the resistance will vary with the extension of the gauge; however, I don't know how to link this to the joystick circuit hardware, as one of the connections is missing Any ideas?

Topic by lesthegringo 7 years ago  |  last reply 7 years ago

### Problems with my CHT (cylinder head temp) gauge.

I have a k-type thermometer mounted on my 12v scooter with a k-type thermocouple running under the spark plug. Things were working ok until I hooked the setup on to the bike itself, powering from the ignition. Now the gauge just reads 0.00C or will rise up to temp and then quickly go back to 0.00. Anyone got any ideas? Is it a voltage/power problem? I've checked all connections. Unit seemed to be working fine on a 12v aux battery I had in the house.Any thoughts appreciated.

Question by tig5 6 years ago  |  last reply 6 years ago

### Really small analog gauge controlled by simple circuit

I'm looking to make a steampunk version of dr who's sonic screwdriver with some LEDs, a tiny recording module for the sound, and I also wanted a little analog gauge with a needle that would activate when the button was pushed. It doesn't have to actually measure anything, I just want the needle to move in some way. i found a little voltmeter on sparkfun that I could probably repurpose, but it's 2x2 inches which is a little bigger than I wanted.  I'm looking for something about half that size. Does anyone know of anything that would fit the description, or a way I could fake it?

Topic by sasham43 5 years ago  |  last reply 5 years ago

### I would like some assistance in designing a digital LED display vacuum/boost gauge for a turbo application. Answered

Hello!   I'm new here. I would like some assistance in designing a digital LED display vacuum/boost gauge with both a linear LED display as well as two seven-segment display modules.   I plan to use a standard automotive MAP sensor to provide the -30Hg to  +30psi signal.   What I envision is having the two seven-segment displays sit next to a row of 28 green LEDs for vacuum to -28Hg, 7 yellow LEDs for pressure from +1psi to +7psi, and 8 red LEDs for pressure from 8psi to +15psi that light up incrementally as the pressure increases or vacuum increases from a center point of zero (clear LED always on).  The problem is that I have absolutely NO idea of where to start other than the layout of the LEDs.  So any help would be appreciated. Thanks! Skullmaster20  (Chris) Edit -----  This is a drawing of what I'm trying to create, and a picture of what I'm going to replace.

Question by skullmaster20 9 years ago  |  last reply 9 years ago

### Can speaker wires be used for power transmission?

I am making my own bicycle light and I decided to use 18 gauge speaker wire.  Speaker wire works well because positive and negative are glued together in the insulation.  It makes for a cleaner wiring job.  I am using the RCA plugs as well.  The light runs at 4.2 volts and 1.5 amps.  Speaker wire is not designed for power transmission but I can use it for that purpose can't I?  Do RCA jacks have a significant amount of resistance?

Question by Noblenutria 7 years ago  |  last reply 7 years ago

### single led light bulbs?

I have some single led light bulbs. I want to string 113 of them. they're 1.5 watts each and 12dcv. what transformer and gauge of wire should I use? G4 socket. there's 24 led's in each light. they're pretty small.

Question by ron.stone.733 4 years ago  |  last reply 4 years ago

### Assistance with a seemingly strange pirani gauge

I'm working on a vacuum system and so far things have gone unusually well for my projects and I really hope to keep doing well on it, but I'm hung up on the vacuum gauges. I've got a PR10-S Edwards Pirani gauge and the internal circuitry is strange. I can't find any literature on it anywhere or any schematics close enough to fudge. So I'm hoping I'blers might have a clue as to what is going on here. EDIT: Added a re-drawn circuit in an estimated configuration After some googling, a 3-wire resistance thermometer seems close to what I have as thats essentially what the gauge is, a clever application of a resistance thermometer.

Question by The Ideanator 7 years ago  |  last reply 7 years ago

### Can I use a regular digital thermometer as a cylinder heat temp gauge?

Hey guys, I want to make a cheap cylinder head temperature gauge for my 150cc scooter. I have owned one before which worked well but it was rather expensive. I'm more interested in being able to detect a temperature spike and avoid a blown motor than determining an acurate temperature. The last gauge I owned used a probe with a ring on the end that acted as a washer between the spark plug and the head. If I buy one of these probes:  http://www.ebay.com/itm/Thermocouple-CHT-Sensor-Probe-Cylinder-Head-Temperature-14mm-/120861470119?pt=LH_DefaultDomain_2 And a digital thermometer with a probe like this: http://www.ebay.com/itm/Digital-Blue-LCD-Temperature-Meter-50-150-Probe-/230650228821?pt=LH_DefaultDomain_0&hash;=item35b3d33055 Could I just splice the wires together and be away laughing? I'd need to find out what the temp range of my engine is first.....my last 2-stroke 150cc ran at about 275F and melted at 400F, 4-strokes should run cooler right? Any thoughts would be appreciated :)

Question by tig5 7 years ago  |  last reply 7 years ago

### I need a source for miniature gears fast?

I'm refurbishing some old aircraft gauges and I need a replacement for a very small spur gear measuring .175" in diameter with 12 teeth not sure what the pitch is, and it needs to be made of metal if anyone has any ideas please help me out? I'm kind of on a short deadline here to so I would be grateful for any info anyone can give. Thank you all.

Question by jeffrey4283 7 years ago  |  last reply 7 years ago

How can I use 2 of the "Cracker Box Amp" circuits to drive standard analogue gauges from the audio out on my computer.  I will use 2 gauges, one for left channel and one for right. I want the gauge to show the amplitude. If I just wire up a gauge to a channel on the audio out then the needle will simply move as if it were a speaker. As I said before, I want the gauge to show the amplitude.

Question by physics_dude 8 years ago  |  last reply 8 years ago

### Need ideas for steampunk pressure gauge.

Well I have all my supplies to start my gun tomorrow but I couldn't find what to make my pressure gauge from i just need a cheap.. ring of some kind and it is harder to find than it may seem. Have any of you made pressure gauges? Share your ideas?

Topic by Ampix0 7 years ago  |  last reply 7 years ago

### light gauge metal bending machine

Well I have searched now for 2 days or so here and on the net for something like this. Does anyone have link to a plan ? free or otherwise ? Thanks Quadranut President of the TNITK Association

Topic by Quadranut 10 years ago  |  last reply 6 years ago

Hi, I recently purchased some 3/8th Bruce engineered hardwood flooring, and was planning on purchasing a staple gun to install the flooring (like I needed a reason for a new toy!), what gauge stapler would you all recommend? Bruce doesn't have specific instructions, it just says the staples should be at least 1 inch long.  I've heard if you buy too big a staple (15.5 gauge), it will cause issues with bumps in the flooring, but I'm afraid if I get too small a staple then it may not attach properly. Please help! As a side note, how big an air compressor would you all recommend?  I was planning on getting a 6gal, 2.6 scfm at 90 psi compressor, and just want to make sure it will have enough power.

Topic by JMH renovations 6 years ago  |  last reply 4 years ago

### Where can you find thick copper wire?

I was just wondering if anyone could tell me how to find thick (#10 AWG or less) copper wire? Either in household electronics or other places where it is free or cheap. I'm trying to make this Instructable: https://www.instructables.com/id/Build-a-Microwave-Transformer-Homemade-Welder/ Thanks for answering my question! Paul

Question by bethekind 6 years ago  |  last reply 3 years ago

### With an electromagnet, if there's a open reed switch betwen 1 end of the coil's wire & powersource, will e-mag get hot?

I'm building an electromagnet. The core is soft iron: 0.5" diameter and 1" long.  AWG 12 wire OR enameled copper magnet wire 32 gauge So the wire is wrapped around the core. One wire end leads to a reed switch which connects to one of the two wires of the 9 volt snap-on battery clip. The other wire end connects straight to the 9 volt snap-on battery clip with nothing in between. Will the wire end that connects directly to the 9 volt snap-on battery clip: A.) use powers and drain the battery B.) heat up the electromagnet (wire & core) If the electromagnet heats up, then how hot does it get? Just warm or really warm? Could it reach hot or HOT levels - hot enough to burn skin, damage any part of the electromagnet, or ignite/melt the carpet (if it was on it)?   P.S.  The final device would have no exposed wires. Thanks.

Question by gatorgirl7563 9 years ago  |  last reply 9 years ago

### Use LED VU meter as Tachometer?

Hi, i want to share and ask something.   Somedays back i bought a digital tachometer with dial and needle. I wanted to test it, so i connected its power terminals (12V) and connected the Tach input wire to audio speakers output (+ve) terminal and played a loud song.  I saw Tach needle going up at certain frequencies. I want to ask that if tach can detect audio signals SAME AS a VU audio meter does. So, CAN A LED VU METER BE CONNECTED SAME IN PLACE OF TACHOMETER  to detect car RPM signals.? Plz help and guide.

Question by waqasjamil 7 years ago  |  last reply 7 years ago

### How many strands of 17 gauge wire twisted equal a 12 gauge wire (approx)

Hi,  I need a 12 gauge wire for the positive side of a small perimeter electric fence. However the only size aluminum wire they sell locally and I bought was 17 gauge wire. My thought is to twist the entire length of two or more strands of the 17 gauge wire together to equal the 12 gauge wire (approx)  How many strands of 17 gauge will it take to do so? One more related question while I'm at it. Does the twist have to be a tight twist or can it be a loose twist? Tight meaning a lot of twists per foot, loose meaning something like 4-6 twists per foot. tia - chase -

Topic by -chase- 3 years ago  |  last reply 3 years ago

### Does a Water Pressure Gauge Work For Air?

I need a pressure gauge that has a "lazy hand" like this one: http://www.plumbersurplus.com/Prod/Pasco-1428-Lazy-Hand-Water-Test-Gauge-0-300-PSI/12178/Cat/787I can't find one for air so I wonder if this one for water will work.

Topic by forkknifespoon 12 years ago  |  last reply 12 years ago

### how do you make ear gauges?

I am trying to make custom plugs for my stretched ears. i was wondering if woods are okay to use and also what kind of paint to use to decorate them with also.

Question by 10 years ago  |  last reply 9 years ago

### 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 7 years ago  |  last reply 7 years ago

### heavy gauge metal tubing shaping question Answered

You know the "heavy" gauge metal tubing you see on swings and roundabouts in the public play parks? What is that called and how would I bend and shape it without having to go to an expensive, specialist shop, please? Pretty much I want to have a straight part about 3 metres followed by a curve of radius approx 1 metre and another 1m straight after the curve. Thank you for reading me and your time to reply.

Question by kevinhannan 7 years ago  |  last reply 7 years ago

### What gauge wire should I use for 8 light bulbs? Answered

I am wiring eight 25W light bulbs in parallel. What is the thinnest gauge wire I can safely use?

Question by randofo 9 years ago  |  last reply 3 years ago

### What gauge is best for a Dynamo generator and can it work with a magnet from a hard drive? Answered

I am try to make a dynamo generator and i am new to this. I dont know what gauge of the coil to get if it will work on a hard drive magnets

Question by tobyscool 8 years ago  |  last reply 8 years ago

### what fuse to use or gauge wire to act as a fuse?

Im making a battery powered coil gun.. each coil draws about 180-200 amps of a pulsed current. I want to know what fuse ratingi should use to protect the circuit.? or if there aint such a fuse.. what gauge wire should i use as a fuse..

Question by icey.hood 4 years ago  |  last reply 4 years ago

### How are we able to know the variable of a Strain Gauge? Answered

Hi, for a school-project I need to measure the weight of an object. Therefore I am using an old weight-scale. The component wich includes 2 Strain Gauges has 2 seperated wires coming out and 1 other wire conected to the Ground. Because we can't find something changing when we measure differend kinds of things, (for example the changing resistor-value) we hope that you can help us. The two wires coming out of the Strain Gauges are connected to an Amplifier (TL081CP). The scale itself is a KRUPS TYP 841 ; 871-B Thanks!

Question by zupperzipper 9 years ago  |  last reply 9 years ago

### How to choose wire gauge for Brushless DC motor?

I'm planning to build a Brushless DC motor, with inrunner perm mag rotor and stator on the outside. How can i determine the proper copper wire gauge for the stator windings? How much current will the motor pull? At first i thought it was just "Power = Voltage * current", so knowing the power and the voltage i should be able to figure the current. However, when the motor is spinning it generates back EMF, which counters the applied voltage and diminishes the current. At no load, the motor should draw no current for an ideal motor, and only a small current in real life to overcome friction and losses. In any case it would be much lower than the nominal current. So, for instance, a 1000w motor at 50v should draw 20A nominal, but in most situations it would be less than that? How much is the starting current, when you have to overcome inertia/tire friction? I know the motor can take higher currents for small amounts of time, before it gets too hot,but how can i determine what will be the "average" current. Is there a rule of thumb that motor designers use?  Also, the amp rating for each AWG seems to vary a lot. Some places list a conservative rating that is used for home wiring. But other places list much higher currents. If the stator is on the outer side and exposed to air, how much current can the copper handle for each AWG? Any insight will be appreciated, thanks.

Question by SlickT 2 years ago  |  last reply 2 years ago

### What gauge wire should I use for doing circuit board work?

Particularly the motorized window blinds controller.

Question by 10 years ago  |  last reply 10 years ago

### Is regular 22 gauge steel wire okay to make earring findings out of? Answered

I am currently using blackspur 22 gauge steel wire to make earring findings but I am worried it could be harmful. Please help? Is this okay to use? No one has yet wore these

Question by The Science Guy 6 years ago  |  last reply 6 years ago

### Can anyone make an instructable on building a gas welding gas kit?

Oxy acetylene kit with torch and gauges? Is it even possible?

Topic by eric m 9 years ago  |  last reply 9 years ago

### Electromagnet Help! How to Make a Small but very Strong Electromagnet???

I need you help smart people of Instructables!I need to make a small Electromagnet, that uses minimum power (by that I mean the battery), but still has to be very powerful. I have a couple of questions that I need you to help me answer:Does the number of coils that is wound to the metal bar effect the strenght of the electromagnet?Does the wire gauge (20,24,28,30,34,36 wire gauge) make a difference is the strenght of the magnet?Does the voltage I supply to the coil effect the Electromagnet?What type of battery is best for an Electromagnet (AA, AAA, C, D), and what voltage (1,5V, 3V, 4,5V, 6V, 9V) ???Here is the thing, I need to make the Electromagnet super strong but taking up the minimum of energy, for example, just 1,5V. The things that are not important to me (doesn't play a factor in my device) is the number of wire winds to the metal rod and the wire gauge! So is it better to just make 1 or more (3,4,5,6...) layers of wire winds???Is it better to use thinner (36 gauge) or thicker wire (24 gauge)???Thank you a lot!Stanislav

Question by comodore 10 years ago  |  last reply 8 months ago

### electrical/electronic

20 amps transformer of 14-0-14 volts from 220 volts bobbin size? primary gauge,turns? secondary gauge,turns thanks.

Topic by imamfarid 5 years ago

### Few questions about coil physics and capacitors.

Hello.  Hopefully there's some smart electromechanical and physics guys on this board. Long story short I have been working on a coil gun project for about a month now. Originally I was using disposable flash camera circuit, a simple push button, and a coil I took out of a fan. The coil itself is roughly 42 gauge wire, wound an inch long with about 14-18 layers. I achieved best results from this coil, about 4% efficiency, using a 200v 470uf capacitor and a magnetic projectile. However when I used a more powerful capacitor rated at 400v 820uf efficiencies were much lower. I realized the coil was limited and the capacitors energy wasn't being maximized. So I bought some 16 gauge magnet wire to wind a new coil. I wound a coil 40mm long, 3 layers thick around a 1 cm pvc pipe. The coil works but once again there is a huge loss of efficiency at higher energies.  So I need to wind a new coil.  Now here are my questions. 1.  I have read that a coil should be about 33% longer than the projectile.  Is this accurate? 2a.  Is there a magical equation to determine the number of layers a coil should have if all other factors are known? 2b.  How many layers of 16 gauge wire should I use for a coil wrapped around a 1/4 inch barrel to maximize efficiency with a 400v 820uf capacitor?  What about a 200v 1200uf capacitor? 3.  Could someone please demonstrate how to convert farads into amps? My main objective is an optically triggered multi stage coil gun with kinetic energy transfer of above 30 joules. I've moved away from flash camera circuitry and am now using dc to dc converters to charge the capacitors.  I need to find out how to convert farads into amps to figure out what kind of transistors I need for the trigger switch.  Any help is truly appreciated.

Topic by MurdaMastaMike 7 years ago

### where to buy a R.P.M. gauge to read the total R.P.M. of my turbojet engine or how to make something this is a turbocharg

i need a device to read the R.P.M.s of my home made turbojet engine? what can i use (turbocharger) weel speed

Question by mirella1925 9 years ago  |  last reply 9 years ago

### Can I make a strong permanent magnet with steel bar by electrical method of magnetism. if possible please guide me? ?

Does the wire gauge (20,24,28,30,34,36 wire gauge) make a difference is the strength of the magnet? Does the voltage I supply to the coil effect the Electromagnet??? Shall i use 304 grade steel rectangular bar for this process ? if any other materiel please suggest me?

Question by babureddy 2 years ago  |  last reply 2 years ago

### MSA SCBA?

Where can i buy a used/new airhawk or firehawk MSA SCBA?

Question by m5industriesinc 7 years ago  |  last reply 6 years ago

### What components would be needed to build an ultrasonic thickness gauge to measure paint the thickness of paint coatings?

I need an ultrasonic thickness gauge, they work by sending a pulse through the material being measured (paint in this case). When the pulse strikes a denser material it returns to the sensor, the delay from the time of the pulse being sent to being received gives the depth. I anyone knows the components that would be needed, or ideally, a set of schematics could you be so kind as to help me out. Thank you.

Question by alkem 9 years ago  |  last reply 9 years ago

### how do I bridge a stereo car amplifier?

Http://www.drdetailshop.com/d2150.htm this source say that my amp is bridgeable and that it can run stereo and mono simultaniously. It is a 2 channel amp, however I only have one speaker.. I need both left and right channels running into the speaker. How can this be done? What would be the impeadance if the amp is running at 4ohms and the bridged subwoofer speaker is 4 ohms? what would be the overall wattage? how do i do this without causing damage toi my sub,amp, or radio? does this put excess strain and/or heat on the amp? if so how do I fix this? is there any wiring gauge problems that i should be concerned about? (18 gauge for input power, 18 gauge for speaker output, plan to lower the gauge of the speaker to somewhere around 12 or 14)

Question by fastcar123 7 years ago  |  last reply 5 years ago