Measuring Volume

So im doing a science fair project for my school and i decided to be different from all the projects. im connecting a 2 channel amp to some old speakers and i was wondering how to measure volume or loudness coming from the speakers when i increase the watts of the amp. my teacher told me theres a specific unit for this and and specific way to measure volume. but so far i cant find much. so i ask you guys for help. please and thanks.

Posted by gpiejai 11 years ago  |  last reply 11 years ago


Measuring audio

I have a project where I need to be able to measure 3 or 4 microphones and decide which one is getting in the loudest input volume. In other words to know who is talking around a four persons table. Does anyone have any idea how to solve this problem? I'm using arduino (http://www.arduino.cc/) for the rest of the project so I'm able to use the arduino to measure dc voltage but how do I transfer the sound wave into a measurable dc voltage? thx in advance / david

Posted by ZrvZ 12 years ago  |  last reply 12 years ago


Measuring an explosion

While this may not be the best instructable I believe it would be helpful for many people doing science fairs (ie: ME). So here is the question said instructable would answer: How do you measure the force of an explosion, specifically of gases or liquids used in fuels? I have been racking my brain on this but everything i have come up with seems like it would be inaccurate. Thanks for any help

Posted by durp123 9 years ago  |  last reply 9 years ago



laser measuring of atrifiact? Answered

I have a friend that needs to make a duplicate of a fragile archeological artifact for further examination. He only needs the face, a single surface, measured and duplicated. I thought of a two technologies project. First a 3D measuring of the surface then a 3D printing of the results. Have we done such a project?  

Asked by kbs2244 6 years ago  |  last reply 6 years ago


How to measure capacitance?

What is the most inexpensive way that I can measure capacitance? I have some photoflash capacitors that aren't marked with their capacitance. I went to radio shack, and the cheapest multimeter that measured it was around 60 dollars. Is there a cheap way that I can find out the rating of my capacitors?

Asked by daa5849 9 years ago  |  last reply 6 years ago


Measuring LED Voltage

Greetings... I have quite a few "salvaged" LED's, none of which have I the slightest clue as to their voltage. I have attempted to measure them using the diode setting on my voltmeter with dubious/mixed/questionable results. Although the measurements are momentary (the reading is barely of sufficient length to note), I can usually arrive at a value. Unfortunately, when I repeat the measurement on the same LED the reading is invariably different. For example, I just measured the value of a random LED (green) and came up with the following: 1.3. 1.4, 1.8, 1.6. I've rounded the values to the nearest decimal point. Are these values through voltage? Are the differences between the readings significant or should I use the minimum when calculating resistor values? I'll, no doubt, have a few more question later on. I appreciate your elucidation on this matter... Best to all, hassi

Posted by hassi 10 years ago  |  last reply 5 years ago


Current measurement with arduino

Hey I try to measure current with hall-sensor amploc 25A, it sense magnetic-fields, offset voltage is 2.5V and I use arduino uno. I get 519 value from analog pin and 37mV/A is hall sensor sensitivity. My formula is outputValue = ((((sensorValue*5000.0)/1023.0)-2500)/37 multimeter shows 0.112amps when I put load but I dont gett correct value on LCD Is my formula OK?

Posted by mattilaniko 3 years ago  |  last reply 3 years ago


Sensor to measure weight.

Hi everyone, I am stuck. I am trying to find a method or sensor to do what I want. Basically, I am trying to make a cheap flat weigh scale- light weight , flexible and portable (carried in a brief case or lap top case); thinner than using load cell sensors. I was hoping for a flat compression fabric , foam or piezo resistive pressure sensor, but have not found what I was looking for. It needs to be able to measure 50 to 250 lbs & fit on a counter. Does something like this even exist? Any suggestions would be most welcome. Thank you Appl314  

Asked by appl314 7 years ago  |  last reply 7 years ago


Follow the bouncing ball!

An article in PhysicsWorld reports on a novel technique for measuring the acceleration due to gravity. The researches used a cloud of ultra-cold atoms and bounced them off a series of upward laser pulses. By measuring the timing of the bounces they could measure g with better than 1 per mil precision.

Posted by kelseymh 9 years ago  |  last reply 9 years ago


Slope Measuring

     I'm interested in making a yardage book for one of the golf courses i play at. The only problem is that i don't know an accurate way to measure the change in distance through elevation. For instance if a shot to a green with no change in elevation requires a 7-iron, then a shot of the same distance that is downhill should require a club that will hit the ball a shorter distance.       My question is, is there a formula of some type that i can enter the rate of change in slope and the distance, and get the actual distance needed for the shot.

Posted by wenpherd 7 years ago  |  last reply 7 years ago



How do I take a contour off my balcony railing and transfer it to a piece of wood?

I have a planter designed to fit over a piece of 2x4 railing, and a railing on my balcony that is smaller than 2x4, and curved, with a non-rectangular side profile. Please see the photos. I have annotated the first three photos. It's hard to see from the photo of the railing, so I drew a side profile of the railing shape and photographed my drawing. The planter has a groove in the bottom so that it'll rest securely on the 2x4. I want to make an adapter out of wood so that the planter will rest securely over my railing. I plan to cut some wood to fit perpendicular to and against the railing, countoured to fit over the railing, and seat a piece of wood over the top of the railing, running parallel to it, to seat the planter into.

Posted by Mr_Liss 4 years ago  |  last reply 4 years ago


How do I measure for getting chair rail molding level and straight on the wall ?

I am going to put up chair rail molding in my living room and I can't figure out how to make sure the molding around the room will look straight and level all the way around the room. Do I measure down from the ceiling every few feet around the room or do I measure up from the floor every few feet to get it even around the room. Its an old house so I'm sure the floors are not level or square. Help! Thanks, Donna :-)

Asked by donnadidit 9 years ago  |  last reply 9 years ago


Measure current and voltage with arduino? Answered

How would I measure the voltage and current of this circuit with an arduino?

Asked by flybye22 8 years ago  |  last reply 6 years ago


Measure Punch Force tool

Hi All, I do understand we all keep creating new electrnoic tools/gadgets everday. But anyone had tried to create a tool which can measure force / intensity of human punch. It is fun to measure your punch force among friends. also if help us to improve your boxing strength. Please share your thoughts on it. Thanks

Posted by VinitV 1 year ago


measure distance with raspberry pi?

How should i measure 10 meter distance very accurately with raspberry pi ?  if anyone knows any sensor that can measure distance of 10 meter accurately please tell me then i will manage ? thank you.

Asked by dharmik123456 2 years ago  |  last reply 1 year ago


electronically measure poundage of an impact?

I'm looking to make a training device that measures the pound force of impact from a strike. I'm sure the is a sensor out there that does this but I don't know what its called.  

Asked by wgriffith 1 year ago  |  last reply 1 year ago


how to measure frequency in this circuit?

i want to measure the frequency of this flasher circuit but i always get a frequency close to that of the mains. I am using a wall wart. i changed some of the components to speed up the flashing but the frequency reading stayed the same. to check my multimeter i tried measuring the frequency of mains and the joule thief circuit and it looks like my multimeter is good. how should i measure the frequency in this flasher circuit?

Asked by codestroy7 7 years ago  |  last reply 3 years ago


How to measure light wavelenght? Answered

Please, don't say 'with a waveleghtometer' . This is a Physics 'practical problem', and I'm thinking interference.

Asked by gruffalo child 8 years ago  |  last reply 8 years ago


How to measure electromagnet by Tesla?

I will be doing an experiment how powerful the magnetic field of an electromagnet, and my guess is the more you twist the wire the more power it generate. But i don't know how to measure the magnetic field by using the unit Tesla.

Asked by defineSCIENCE 2 years ago  |  last reply 6 weeks ago


How to Measure From a Picture

I am trying to make a table from a picture in a magazine, which has some intricate lathe work that I want to duplicate. The problem is the picture was taken at an unknown angle, and when I try to scale up from the picture my measurements come out screwed up. Is there something I can do that we allow me to find the right measurements?

Posted by Sedgewick17 10 years ago  |  last reply 2 years ago


Measuring the piezo transducer with oscilloscope

Hi, I am conecting a piezo disc as a microphone to pick up vibrations. .The problemm is when I measure the signal with osciloscope I am getting a messy and modified one with many noise  If I am measuring it with PC oscilloscope (threw the sound card mic input) I am gatting a clean desirable signal What is the true signal and what I am doing bad with the oscilloscope. Thanks! Anna

Posted by AnnaL3 3 years ago  |  last reply 3 years ago


Power supply amp measurement?

My power supply says it can supply 12 Volts @ 10 amps.  It used to power 2 linear actuators drawing max 4.6 amps each, but no longer does. It still supplies 12V measured by multimeter. Is there an easy way to figure out how many amps it now supplies?

Asked by thisisted 2 years ago  |  last reply 2 years ago


Measuring oscillation of a multi tool

I have a harbor freight oscillating multitool that is advertised as oscillating between 10k and 20k oscillations per minute. In reality to speed control goes from 0 opm to an unknown value. I’m trying to set the tool to oscillate at 35 Hz. What is the best way to measure the frequency of the tool and set it to 35 Hz?

Posted by rednax718 10 months ago  |  last reply 10 months ago


How to Identify or Measure Inductance?

I am gathering the parts for an ible, but I am short one part: a 12mH inductor.I can spot some inductors in electronic garbage - the wire coiled around a ferrite loop - but there are also solid state inductors. Plus, the inductors are not usually labelled with their values.How can I measure the inductance of an inductor with a volt-meter and an ammeter, but without access to a sine-wave generator?Is there some simple trick that would get me "close enough" to the true value? What would be really useful (but probably doesn't exist) is a chart or formula where you plug in the size of the core and the number of turns around it and out pops the inductance value. ?

Posted by Kiteman 10 years ago  |  last reply 5 years ago


measuring petrol/ethonol accurately

G'day All, If this has been done before, I apologise, but I have not found anything when I have searched. I am a team manager for a team of students who need to design, construct a three wheeled vehicle. The test is a 24 hour "trial" (more like a race ;-) ) We have been competing in a category for "Hybrid Vehicles" which an additional power source to asssist the rider.  In our case it is a 50cc engine using a friction drive arrangement so we can disengage it if required or if we desire.  The reason for this is that we only recieve 3 litres of petrol for the event............  This is my problem.  I have not been able to measure petrol in the tank accurately enough.  Over the last two years I have had one litre left or ran out after 21 hours.    I have been thinking of using a strain gauge or load cell to measure the weight of the tank.  I'm thinking it could be as simple as powering up the load cell with the appropriate voltage, and measuring voltage drop across it, maybe with an added resistor. Or it could be made more complex by using a circuit to drive a number of LED's giving an indication of the fuel in the tank. If anyone outhere has any ideas to do this simply and reliably, I would love to hear from you.  If it is more complex then so be it. Here is a link to the event to give you an idea of what it is about http://racvenergybreakthrough.net

Posted by coln72 7 years ago  |  last reply 6 years ago


Measuring a Bluetooth modules output? Answered

There is a serial Bluetooth module that I have used before on an Arduino project but now I'm trying to use in a project without the Arduino. Basically I need it to be an electronic trigger, I don't care really what the signal is just how long and the voltage and current. There are 4 pins on the module: Vcc, GND, Tx, and Rx. There are 2 open pads: Key and State. When I send a command from my phone the module sends a signal out the Tx pin, and it is this signal I would like to measure so I can pick a command with an appropriate signal and tailor the rest of the circuit accordingly. I tried a voltmeter between Tx and GND but saw no signal on any level measuring DC. Is there something I'm missing? Is the signal more complex or different, or is that test setup flawed? I tried other combinations, Rx-GND, Tx-Rx, RX-Tx, GND-Tx, GND-Rx but saw nothing.

Asked by bwrussell 6 years ago  |  last reply 6 years ago


Measuring Current of 24v dc motor

How to measure the max current of 24v dc motor.. please give me step by step guidance. many thanks

Posted by epple 7 years ago  |  last reply 7 years ago


12v DC battery amp measurement? Answered

HI, I have a 12v dc battery and I wanted to measure the amps. Can anyone show me how to hook up the multimeter? Thanks

Asked by amantux 7 years ago  |  last reply 2 years ago


is there any way to measure rpms cheaply?

We are making wind turbines in one of my classes and my team is making a tesla turbine as ours. we want a way to measure how fast the disks are spinning. please help.☺

Asked by DehLeprechaun 7 years ago  |  last reply 4 years ago


create "black body" and measure radiation

Hi i have been looking for some experiment about black body radiation how can i make a black body at home and how can i measure the black body radiation using inexpensive materials... i would like to measure plank's constant and so... i didn't find anything on the net any suggestions? thank you!

Posted by yitzik25 1 year ago  |  last reply 1 year ago


What are the measurements of the frets on a Mcnally Strumstick?

 I want to build my own strum stick, & can't find what the lengths in between each fret should be.

Asked by jclay422 9 years ago  |  last reply 7 years ago


High Current measurement using Arduino?

I need to measure Current from a welding machine to make a alarm if it goes down below some level for ensuring better quality.The current normally set is of the order of 200A max with around 100V DC.Not sure if i could use some clamp-on meters and decode the values. Shunt resistors may be a better option. But to make a signal conditioner to convert the ma output will be a problem i guess..is there something i can do with Arduino.. any ideas guys....?

Asked by chuppandi 6 years ago  |  last reply 6 years ago


how to measure inductance using a bridge?

My LCR meter can only read inductances of mH to a few Henries. I need to make a 470uH inductor, since in my place inductors are not so common. How can i measure inductances at microhenries if my LCR meter's reading capability only ranges from millihenries to henries? Someone told me to use bridges like wheatstone bridge or maxwell bridge to have an accurate reading, but i don't know how to do it. Can you suggest any reference? I prefer doing wheatstone. Thank you in advance :)

Asked by codestroy7 7 years ago  |  last reply 7 years ago


Measure RPM and MPH on motorcylce with Arduino

Hi all, I have an idea for an Arduino based instrument cluster for my cafe racer (1980 xs400). My question is what kind of rotary encoder I should use to measure the rotation from the cables coming from the engine block and front wheel that went to the original cluster (shown in pictures). I want something that won't break at higher RPMs and is more or less water proof. I have an idea of how to code this on the software level as well, but I'm not to experienced with C/C++ so any help there would also be appreciated. The end goal for this part of the cluster is to output the RPM and MPH to respective WS2812B 5050 LED strips, and possibly a small oLED later down the line. If something could be made more clear on this post let me know and I'll try to elaborate. Thanks again

Asked by AedanGraves 6 days ago  |  last reply 5 days ago


Circuit to measure internal resistance of a battery?

Dear All I know very little about electronics! So please pardon potentially dumb questions! My objective is to know when to (properly) discard a rechargeable battery and buy a new one. I want to be able to read the voltage of a rechargeable battery when freshly charged. Then I want to be able place the battery under load and measure the voltage as well as amperage again in order to compute the internal resistance. I intend keeping track of these results for this (and other batteries) over time (and also comparing the data to other similar batteries I have). I have created a simple schematic of what I think I aught to do (attached to this post). Known parameters are: - Battery voltages vary from 3.2 to 4.2 V depending on model and age - Battery capacities vary from 700 mAh to 1,200 mAh depending on model and age What I would like to do is: - Have one circuit where I can measure the unloaded voltage (and amperage) - Change a switch and then place the battery under load - with an LED indicating when this circuit is on permitting me to measure the loaded voltage and amperage. What I don't know is: - What size fuse do I use (do I need one?) - What size / voltage LED should I use considering the different voltages of the batteries? - What resistor should I use for this LED? - What resistor should I use to place the batteries under load?  How large should this load be to sufficiently stress the battery but not damaging it? (The 3 Ohm in the diagram is a total guess!) I know I can go and read up on this on various websites - but, being honest - its so much easier to ask! Your advice would be most appreciated.

Asked by Farawayman 4 years ago  |  last reply 4 years ago


Having trouble measuring voltage with arduino.

I have posted this question before but I’ve made a few changes with my circuit with no luck. I’m trying to make a variable lab bench power supply with an lcd screen to read voltage and current while adjusting them. I’m using TL431 to have a 2.5v Vref and  a op amp in voltage follower configuration with 10M and 1M trimmer (Divider) on the input to finely calibrate 38v down to 2.5. The op amp is acting like a buffer. This is the code I've come up with: float volt; int sum = 0;                   unsigned char sample_count = 0; #define NUM_SAMPLES 10 void setup() {   analogReference(EXTERNAL);   Serial.begin(9600); } void loop() {   while (sample_count < NUM_SAMPLES) {    sum += analogRead(A0);    sample_count++;    delay(10);     }    volt = ((float)sum / (float)NUM_SAMPLES * 2.5) / 1023.0;     Serial.println(volt * 15.2 ,3);     sample_count = 0;     sum = 0; } Parts list: LM358 (for now, will upgrade to a unity gain stable op amp) 10M 5% resistor 1M trimmer Arduino Mega (Will use a pro mini in the final circuit) Breadboard (Will this effect my readings?) TL431 (2.5v Vref) Yes I now the LM358 is not suited for this application but I don’t think this will affect my readings by much, about 5% maybe. Will it? This code is gives me OK values at start but when I start to decrease/Increase the voltage. It lags behind and offsets by 1-2 volts on the reading. My goal with this project is to read (LIVE, meaning while changing voltage with buttons and see it change without any offset/lag) Voltage with a resolution of +-5/10mv accuracy and also read current (But thats for a later day). One last thing, I’m 16 so a lot of electronic terms tend to go over my head so please while giving an answer keep it simple if possible. Thanks :D

Asked by faraz ahmed khan 1 year ago  |  last reply 12 months ago


Laser cut ruler? Answered

I was thinking about a laser cut ruler. Is it really pointless? It will be made out of blue light-gathering acrylic. I was just wandering if it was going to be useless...

Asked by knektek 8 years ago  |  last reply 8 years ago


Export Google SketchUp as just the faces and measurements?

I made a simple chair in Google SkecthUp and wanted to make it out of cardboard(lot of time on my hands). I was wondering if their was a simple way to export all the faces and measurements in the .skp file?

Asked by Chromatica 8 years ago  |  last reply 8 years ago


HELP measure resonant frequency on induction heating. ? Answered

Dear  All..... In this circuit and formula  on (GOOGLE). Please could you help me to know 3 questions: -How  I can measure resonant frequency  of this circuit, because it has   2 L and 2 C on this circuit?. - where I  must to put the probes in this circuit for measures frequency? - If I want to used less power(less heating) I must change L  or C  or both?  Thank you so much in advance  for your time.

Asked by lam 6 years ago  |  last reply 6 years ago


How to measure the distance up to 200m (with arduino)??? Answered

Hi ... how would you measure the distance up to 200m using the arduino ??? 1. What would you use ??? 2. Is it possible to modify the PING))) sensor to be able to measure such distance ??? 3. Do you think, that this radar kit www.hobbytron.com/r-sg7.html could me modified to do the job ??? There is a 'pdf' file for more information. 4. Or would you use laser - how ??? Thank you in advance for you answers/suggestions. zholy

Asked by zholy 9 years ago  |  last reply 6 years ago


Push button duration measurement inside FPGA

Hello, I need to measure the time between press and release a button in an FPGA (time between rising and faling edge) and dispaly the time result the seven segment dispaly of the FPGA , I do somethink but it doesn t work , can any one help please or give a program ,????

Posted by mirabelle275 11 days ago


How to measure max output current of transformer ?

Asked by Rendydevara 7 years ago  |  last reply 7 years ago


Having trouble measuring accurate voltage with arduino.

For a week now I’m trying to get very precise voltage readings with no luck so far. I’m using a voltage shunt regulator (LM431) for reference but still. My goal is to read values low as a 1mv change. I’m using a voltage divider to convert 38 volts to 4v (According to my vref). I've read that 10 bit ADC in atmega328 is enough for this job. Is it or am I doing something wrong? Thanks P.S i have made a lot on changes to my circuit so please go over to my new link to get up to date. Ive read all of your feedback and tried to implement it. Thanks a lot for all your answers.  LINK: https://www.instructables.com/answers/Having-trouble-measuring-voltage-with-arduino/

Asked by faraz ahmed khan 1 year ago  |  last reply 1 year ago


How can I measure grams without a scale?

For those who have done the measurements for thermite..  I know you're supposed to measure the iron oxide and AL powder by weight but does anyone have the measurements like in teaspoons or whatever because I dont have a scale.. Thanks in advance for your answers.

Asked by jules15 8 years ago  |  last reply 8 years ago


how would you measure the force that something exerts?

Asked by kazpro 7 years ago  |  last reply 5 years ago


How Do I Measure Coefficient of Productivity (COP) ? Answered

I just recently ran into this term and cant find the definition on the internet.  Can some one please explain to me what Coefficient of Productivity is and how to measure it? Thanks, Kalrag

Asked by Kalrag 8 years ago  |  last reply 8 years ago


How to measure pre-shirred material for a summer dress?

I am new to making clothes and am self taught on my sewing machine. I bought this really cute cherry pre-shirred material, and am trying to figure out how to measure it to fit my body right. Is there a special way I need to do this, or is the answer right under my nose and its passing me by? Any adivce would be greatly appriciate. So, again, my question is, How to I measure the pre-shirred material to make my summer dress?

Asked by 9 years ago  |  last reply 8 years ago


Sensor to eventually measure weight ( up to 250 lbs)

Hi everyone, I am stuck trying to find a method or sensor to do what I want. Basically, I am trying to make a cheap flat weight scale- light weight and portable; thinner than using load cell sensors. I was hoping for a flat compression fabric or piezo resistive pressure sensor, but have not found what I was looking for. Does something like this exist?

Posted by appl314 7 years ago  |  last reply 3 years ago