My project X My Car = Lumber

Not sure where to post this but figured I'd at least got the right website. I drive a Scion xB (aka the angry toaster) so I know what lumber I can carry. I'm looking for a calculator that I can tell the number of pieces, their dimensions and what the max of my car is capable of and receive the number of different pieces of lumber I can should buy to complete the project. Does such a thing exist? The math and algorithm is relatively simple. I'm just to drunk to work it out at present and it'd be a site well worth having in my bookmarks. If you know of a site this is a quick post, if not what would you like to see in such a site? Example: Building drawers for my small work space (13' x 6')  the structure I've come up with to support the drawers requires a frame of  2x4's: 3x sides: 2x56" 3x7" cross members: 4x 25" 2x 54.5 How many 2x4's should I buy if the max length of 2x4 I can fit is 8'? (I love my scion xB) 

Posted by MichaelD158 2 years ago


Ultimately Simple Calculator

Listed in the Built By Monkeys blog from Design News, comes the ultimately simplistic calculator that anyone can use. It can be found At this location

Posted by Goodhart 8 years ago


TI Calculator Help

I have the TI-84 Plus Silver Edition and I have some questions. First I need to know how to graph the equation (x is greater than or equal to y) Also I put the quadratic program on my calculator but it gives the answer in decimal form, how do I view it in fraction form or is that even possible??

Posted by thouse 10 years ago


Calculator Programs for Math

I've been working on some programs for my calculator recently and have decided to share them. I made these myself from scratch. If you want to modify go ahead just credit me. Don't sell them. And don't use them in math class if your teacher says not to. The programs are a follows: a quadratic formula solver, parabola solver, slope of a linear equation finder, and y-intercept finder. The programs work on TI-83's and TI-84's. If you have questions on how to use them or how to put them on your calculator please leave a comment!

Posted by sardines454 11 years ago


TI-connect for calculator

I'm having trouble loading "TI-connect" on my mac so that I can write programs for the ti-84 on the computer. After downloading ti-connect, I click on it, and it seems to want to install it again. I've done the complete loop, repeating the download process about 4 times.  Do any of you know what to do?

Posted by Toga_Dan 6 years ago


Stack Calculator (RPN)

Has any one made/have plans for making a stack calculator (reverse polish notation)? I kinda want to make one this summer so if no one else puts something up maybe I'll try to post something in the next couple months.Here is some info on RPN for anyone interested:http://en.wikipedia.org/wiki/Reverse_Polish_notation

Posted by hunt3131 9 years ago


Diode Calculator will not work

I've been working on a diode only (well, plus switches for input [numbers, yet there's only one pad! not one for each digit], resistors for various things, and LEDs for the display) calculator that could add two two digit numbers (xx+xx=xxx) for a while, putting countless hours into it.I have deemed it impossible.There's so many problems with a mass diode resistor network that is just won't work. As some and gates conduct then some other gate (like it's suppose to) conducts, and eventually causes a voltage divder (with the pull up/ pull down resistors) and the output gets wacky and there's no wway of amplifying the signal.The diode adder is dead

Posted by guyfrom7up 10 years ago


Personal electronics theft prevention

My daughter is going into high school and has had her scientific calculator stolen for three years in a row at school. These are pricey, running from $30-$40 each. Besides that, all the other things in her pencil bag, like compasses, triangles, pens, mechanical pencils. Frankly, I'm sick of my daughter not being prepared for class and spending money for the reprobates to just steal it.  Is there any way to tag her calculator economically to track it down?

Posted by hugabugs 5 years ago


Help with resistor calculator for LEDs

Hi everyone, I decided to try and build some LED lighting and found a few online resistor calculators but, I'm not exactly sure what to put for the voltage drop and the LED current (other than using the generic suggestions from the online calculators). So here are my questions... Is the "forward voltage" what you enter for the "voltage drop"? If so, do you use the lower or higher number? For the LED current, do I use the "max cont. foward current" or should I just put in the suggested 20mA? what kind of a difference would one be over the other? These are the specs given for the LED I'm going to be using (minus the unimportant stuff). Forward Voltage (V) : 3.2 ~ 3.8 Reverse Current (uA) : <=30 Absolute Maximum Ratings (Ta=25°C) Max Power Dissipation : 80mw Max Continuous Forward Current : 30mA Max Peak Forward Current : 75mA Reverse Voltage : 5~6V Thanks in advance.

Posted by GSXR 8 years ago


How to make a calculator that divides by zero?

Hi New to the forum so not sure how it works here but basically asking a request for a instructable for any shop brought calculator that when asked to divide something by zero returns a number, maybe a  random number, but hopefully 42 everytime. Is this possible and if so could someone post the instructable? Cheers

Posted by blind oly 10 months ago


Interfacing With Glass Calculator LCD displays.

I have a bunch of those glass calculator LCD displays laying around at home and I was wondering if anyone had figured out a way to use them as regular LCDs. I have never been able to work with them in the past because they have all used the ribbon cable or foam thing to connect to the PCB. Is there another way that does not involve making a special PCB and enclosure to work with it, like with copper wires and some soldering?

Posted by awilson56 5 years ago


Calculator data into a PC

I have a Check and Correct Calculator with 120 steps, I need to upload the data stored on the memory of the calculator, I mean the 120 steps all together into a excel file, or to a text file. Any ideas on how to convert a calculator into a small pad?

Posted by lmarkez 7 years ago


Resistance calculator using flash

I just created a resistance calculator using liveswif (its like macromedia flash only not as good) and programmed it with actionscript.   I can't figure out how to get the numbers to line up properly, although the calculator still works.   If you have a resistor and need to find out how many ohms it is, the calculator will do it.   http://www.gamesfree4u.com/resistancecalculator.html

Posted by pennsteve 8 years ago


555 Timer Calculator

Hi everyone, I was looking around on the internet a while ago for a calculator for 555 timer circuits and couldn't find one that worked very well. Then I set about making my own in a Excel spreadsheet to calculate the frequency and duty cycle for me. I have decided to share it with everyone to help others. It is quite simple. Enter your vaules into the yellow boxes and get your frequency and/or duty cycle from the blue boxes.

Posted by qwertyboy 9 years ago


Budget Keeper Fridgemagnet, is this doable?

Howdy folks, I have an idea for a budget "keeper" and I'd like to know if it is doable. Here's my idea: Make a small (5"x7" maximum) lightweight budget calculator that goes on your fridge. It will keep "budget limits" for a few categories: Grocery, Fast-food, Non-Food, Car and "other". expenses. The intent is that at the beginning of the month you'd enter your budget limits for each category. Then when you get home each time after spending some money you'd enter in what category you spent in and how much. Then it would tell you how much you have left! This would be so useful to me! Maybe others? I'm not a circuitry/soldering kinda guy, but I am a C#/VB programmer, so I could write the logic on that level. Is this something that is doable from an "instructables" point of view? Thanks!

Posted by jimbox31 11 years ago


Resistor Voltage Drop

Is there any way to calculate the voltage drop of a resistor value? For example, if I had a 47 ohm resistor, would its voltage drop equal -30V, -857358V, or -0.5V?

Posted by puffyfluff 10 years ago


Interfacing to a TI Graph Calc

I was looking at how to interface an lcd screen to a microcontroller and learned they have a 14-16 pin interface. Guess what I found out? An old Texas Instruments calculator I tore apart has a 14 pin interface on the lcd screen, with the first two pins being power! Just like on a regular lcd screen! I am going to atempt to interface my OOPIC to it! If this works, I promise you there will be an ible!

Posted by gimmelotsarobots 10 years ago


Amazon's very expensive cable, and the comments for it.

Http://www.amazon.com/AudioQuest-K2-terminated-speaker-cable/dp/B000J36XR2/ref=pd_sim_sbs_e_18 I was flipping around on Kotaku, and came across a page talking about the MASSIVE rip-offs involving HDMI cables. I read the article and found this link in the comments. This is a $9,000 audio cable from Amazon. I went down to the comments (mostly to see if some idiot bought this), and found some interesting comments. And by interesting, I mean I fell out of my chair laughing.  -------------------------------------------------- Some comments: " We live underground. We speak with our hands. We wear the earplugs all our lives. PLEASE! You must listen! We cannot maintain the link for long... I will type as fast as I can. DO NOT USE THE CABLES! We were fools, fools to develop such a thing! Sound was never meant to be this clear, this pure, this... accurate. For a few short days, we marveled. Then the... whispers... began. Were they Aramaic? Hyperborean? Some even more ancient tongue, first spoken by elder races under the red light of dying suns far from here? We do not know, but somehow, slowly... we began to UNDERSTAND. No, no, please! I don't want to remember! YOU WILL NOT MAKE ME REMEMBER! I saw brave men claw their own eyes out... oh, god, the screaming... the mobs of feral children feasting on corpses, the shadows MOVING, the fires burning in the air! The CHANTING! WHY CAN'T I FORGET THE WORDS??? We live underground. We speak with our hands. We wear the earplugs all our lives. Do not use the cables!" - By Whisper ---------------------------------------------------------------------------------------------------- ---------------------------------------------------------------------------------------------------- "If there is one cable I would whole-heartedly trust to my Chimera-hunting needs, this would be the cable. No other cable has the tensile strength to properly and efficiently garrote a lycanthrope, asphyxiate an Esquilax or even gag a mermaid. Last week, using my trusty AudioQuest K2 (retrofitted with lead weights, bright orange latex paint and a generous coating of crushed glass stolen from the window of an abandoned church at midnight), I managed to snuff 3 golden unicorns in swift succession!  Pros: Quickly tears through scales, fur, bone, and adamantium with ease  Coils and uncoils from hip holster (optional) quickly and quietly  For a product fabricated from 1,000 Onyx Dragon fetuses, the price is unbelievably reasonable!  Cons: Shipping from the R'lyeh took far too long  Doesn't come in 10' lengths (which would be perfect for hydra, cerberii and other multi-headed creatures)  After every use, I can feel 6 ounces of my soul slipping from my core into the ether. But this may be due to the fact that I prefer to work without gloves. YMMV.  Overall, I would recommend that any hunter buy one, nay, two, of these immediately, and experience the difference that upgrading to the K2 will make in your next quest!" - By Valannin "Pantheon Outcast"

Posted by ry25920 7 years ago


How to calculate the percentage using cmd?

Heyyyyyyyyyy...how to calculate the percentage of two numbers using cmd?

Posted by Subhasis Biswas 4 years ago


WANTED: Your Ways to inscribe / label / letter plastic cases 'n stuff REWARD :)

Hi Folks Did you ever successfully apply a small lettering onto something? Your methods of making labeling/lettering on a quite small scale would be very appreciated!Maybe people from the miniature/model scence have some idea?I want to 'casemod' my TI-92 Plus and CBL-2 to look similar AND nicer. They are housed in some not that beautiful grey plastic. I thought of just applying some primer and paint, but that would make all the important small inscriptions disappear and since there are plenty of them, I can't have that. I bought some letraset lettering sheets on ebay, but those are only one color and a bit too big...WANTED:A method to apply small (<=0,1 inch) yet accurate lettering onto plastic/metal/paint. Durability is not important since I will apply about 5-10 layers of varnish. Some opacity/covering power would be good though. And I need to be able to do it in at least two colors.REWARD: I offer two (full) cases of Altoids for the person, whose technique I use in the process. (Of course an instructable will document the build!)This is kind of arbitrary but I want to spice up the deal a bit...Thank you!Maniacy

Posted by Maniacy 9 years ago


Customize CASIO® logo from Calculator [REQ]

I want to change/customize/replace the CASIO ® logo flashed while turning off my fx-991ES calculator to make it more cool . I want to replace it with a desired word/letter like for example my Name or some initials. So please make this COOL instructable . The image of that Calculator screen flashing logo is attached to make it more clear what i wanted to say. Thank You...

Posted by SïÐdhèshS 2 years ago


Calculator IM

At my school we are required to have these TI-83 plus calculators for math. Of course we have classic games and stuff that we put on there, but we want to try to put an infrared emitter and detector on it so we could send IM's within the room to each other. Kinda like texting. Could anyone help us by suggesting ways to do this?

Posted by Jordo 10 years ago


How do I calculate what resistor I would need?

Ok, so I'm working on a project. I need to know how I can reduce 18volts down to 12volts. If someone would explain how to calculate this myself I can figure out what resistor (or series of resistors) I need.

Posted by the.texas.trucker 10 years ago


Best IC Calculator Question

I am looking for a chip just like the ones used in any calculator that does multiplication addition and subtraction. THe device i am looking to build has to be as thin as a credit card have a 8 character segment lcd and only be able to do addition and subtraction. so i need to be able to have buttons" 1 to 0 + - and = and . "nothing more. i looked at some attiny ics but they require a another ic to drive the lcd. also the the data entered need to stay in if the power of the ic goes out. most calculators have only one ic, any idea what the best ic for this application will be? thank you in advance. i need something this small. http://www.logopremiums.com/calculator-ballpoint-pen-HWK922LP.jpg Thank you

Posted by virgiltu 5 years ago


Lithium ion battery capacity calculations?

     I'm working on a project that uses lithium ion batteries as the power source and cannot figure out how to calculate how long it will run for.  I have four 2.6Ah batteries connected in parallel, giving me a total of 10.4Ah of capacity.  They're lithium ion so the nominal voltage is 4.2v and the minimum I want to bring them to is 3v.  My project draws a constant 2.85W of power, regardless of the voltage put into it.  What I want to know is, is there any way to calculate or even just approximate how long these batteries will power my project before they run out (the voltage drops below 3v)?  The batteries are high quality, so the 2.6Ah rating is pretty reliable.  Let me know if there are more specifications needed or something.   Thanks ~Dudes

Posted by dudes 2 years ago


need some way /someone to calculate pressure downwards VS. inwards on ball?

I´m building an automatic toolchanger for my cnc mill. i need some help to calculate how strong a spring needs to be, for a ball to be pressed strong enough inwards to hold a cone (tool holder) I need some fomulas thx, hope you get what i need :)

Posted by lordl9999 5 years ago


Magnetic spec

I was wondering how big a cylinderical grade N42 NIB magnet i would need to pull a copper weight of 20 grams from 3inches? I dont know how to calculate so... If you could, that'd be great

Posted by lifelong-newbie 10 years ago


resistors and watts

I know how to use ohms law to calculate what size resistor I need but what I really need to know is how to tell/calculate what watt rating I need to use whether it be 1/4, 1/2, 1/8, 1,10 and so on.

Posted by pattyshaw 6 years ago


LED calculator

Is there an easy formula or an online calculator to figure out what type of resistor I would need to hook up to an LED to keep from blowing it? I know you can also have a string of LEDs and the more you use you won't need resistors. I'm just trying to figure out for different projects with different batteries, what the most efficient circuit would be. Also what does T1 3/4 mean? I noticed that on the 5mm LEDs. How does it differ from ones without a designation?

Posted by mrshow555 11 years ago


Cheap calculator hacking

I put together a Solarbiotics Magbot Pendulum and it has a period of one second. I measured this by using a stopwatch and counting the swings for five minutes. . What I would like to do is count the number of times it swings back and forth over an extended period of time, for example 24 hours.   I came across an article showing how to use a cheap calculator to count the number of turns a shaft makes. A cam attached to the shaft presses the "+" key each time the shaft turns one full turn. to use it, you clear the calculator and press the "1" button. Then every turn the cam presses the "+" button and 1 is added to the sum being displayed. Every cycle of the pendulum causes the LED to flash (pulse)  once. I'd like to use these pulses to do the electronic equivalent of pressing the "+" button.  It might be possible to count these pulses using electronic circuitry (decade counters) but electronic calculators only cost about a dollar of two and I'd like to give that a try. Any suggestions would be appreciated.

Posted by koyescha 4 years ago


Cheap calculator hack

I put together a Solarbiotics Magbot Pendulum and it has a period of one second. I measured this by using a stopwatch and counting the swings for five minutes. . What I would like to do is count the number of times it swings back and forth over an extended period of time, for example 24 hours.   I came across an article showing how to use a cheap calculator to count the number of turns a shaft makes. A cam attached to the shaft presses the "+" key each time the shaft turns one full turn. to use it, you clear the calculator and press the "1" button. Then every turn the cam presses the "+" button and 1 is added to the sum being displayed. Every cycle of the pendulum causes the LED to flash (pulse)  once. I'd like to use these pulses to do the electronic equivalent of pressing the "+" button.  It might be possible to count these pulses using electronic circuitry (decade counters) but electronic calculators only cost about a dollar of two and I'd like to give that a try. Any suggestions would be appreciated.

Posted by dickb24 5 years ago


Please help to Calculate volume / weight of Alumium

I wish to make a mold that will take exactly 1kg (or whatever weight) by calculating the volume of the mold before construction. Therefore 1cc of aluminum will weigh? 1gram will occupy how much space? 1kg? I know 1 could take 1kg and use it to measure displaced water, but alas do not have even close to an accurate enough scale. Did try to figure it out from the data on wiki and other sites, but Double alas - it truly is Greek to me.

Posted by Karroo Oakey 8 years ago


K'Nex Computer & Calculators!

Check it out: some students Olin College have been building calculating devices entirely out of K'Nex! These are totally fantastic old-school devices, ball-powered. My inner geek is having fits of joy.Check out some pictures of their stuff here.Unfortunately they don't have complete instructions up! They should definitely post the whole thing on Instructables- I sent Matt a message earlier today. If you want to see his project on the site, drop Matt an email and tell him he should post the directions on Instructables! His contact info is here.

Posted by canida 11 years ago


Programming in TI Basic

Just wondering if anyone else here programs their TI calculators using the built in language.

Posted by sardines454 11 years ago


Gravity Lamp Calculations

Http://www.core77.com/competitions/greenergadgets/projects/4306/ some people might recognize this little invention a while ago.  Well I recently wanted to make one after a freak snow storm rocked central pennsylvania (didn't have power for 2 days, it sucked balls).  But, after doing the math, his claims seem impossible.  Someone check the math for me: Facts of the Gravity lamp (with data in favor of the lamp_: output: 600 lumens weight falling: 50 pounds distance falling: 58 inches (in reality it's a bit shorter, but i'm just putting everything in favor) for ease of calculation and in favor of the lamp, assuming 100% efficiency. lasts for 4 hours calculations: 600 lumens = 7542 candellas = 7542000 mcd the highest efficient LEDs i could find output 120,000mcd at 20mA (0.02 amps) with a drop of 3.2 volts 7542000mcd/120000mcd = 63 LEDs 1 LED = 3.2 volts * 0.02 amps = 0.064 watts 63 LEDs = 4 watts 50 pounds = 22.68 kg on earth: the force of the weight is 22.68*9.8 = 222.264 newtons 58 inches = 1.47 meters 1 joule = 1 watt * 1 second = 1 newton * 1 meter 222.264 newtons * 1.47 meters = 326.73 joules 326.73 joules / 4 watts = 81 seconds, NOT 4 hours looking back at it, I think i messed up the calculations at earth's gravity, because that part is just totally wrong :P.  I'm not far enough into my physics class to know how to properly calculate that, could someone else?

Posted by guyfrom7up 9 years ago


Robot wheel torque to weight calculation help

It's been a while since I've had a physics class and I'm scratching my head to remember how to figure out the following problem.  If I have a pair of motors for a robot wheeled base that have a torque of 6 lb/in each and, lets say, a 5 inch wheel, how heavy of a robot can I build?  I'm starting to build a robot base that I would like to future proof so I can add extra electronics and hardware and start with a battery with plenty of power (which of course means more weight).  I'd like to avoid building the robot and find out later that the motors don't deliver enough force.  Any ideas?

Posted by Grosseinator 7 years ago


resistor Q

I'm building an LED circuit and I have the right ohm but the W is 1/2 when 1/4 was calculated out?

Posted by mrshow555 11 years ago


Button pressed

Hello guys this is a weird question but do you know a way that i can calculate the time while i press a button on my keyboard

Posted by OmarB8 2 years ago


Speed sensor

I have a 60 tooth ferromagnetic ring gear with a speed sensor attached. Each passing of a tooth creates a pulse in the sensor sending a signal to the ecu for calculation of attained rpms. It calculates the interval between the teeth to obtain the rpms, thus determining when to kick in the rev limiter on my 06 polaris ranger XP 4x4. Is it possible or even practical to eliminate every other tooth to "fool" the sensor into a lower rpm reading, and creating higher rpm levels within the motor?

Posted by hiatt65 11 years ago


Electromagnetic and Magnetic Levitation

Hi! I am setting up a levitation system and need to estimate the amount of voltage and current that is needed for a 2" dia. coil to produce 4800 Gauss. I don't have any restrictions/requirements on the core, number of turns, etc as long as it would produce 4800 Gauss with a 2" diameter. How can this be calculated? (I have spent a lot of time googling for such information, but I am pretty confused and didn't find how to calculate this) Thanks!

Posted by J50Nunlimited 9 years ago


Fake devices

I just took apart a cheap "solar" calculator that was actually powered by a small coin cell. The "Solar Panel" was colored cellophane. You ever find something like this?

Posted by Rotten194 9 years ago


Calculating Drag When Firing Potato Launcher and Design Specifications

I'm interested in making a pneumatic potato launcher, I've found plenty information on that but I want to hit a target 255 meters away at an angle of 45 degrees. I calculated that I would need an initial velocity of approximately 50 m/s without wind resistance. The object being launched is an average sized potato under normal weather conditions. With wind resistance, what initial velocity will be required to hit the target? Please explain the process by which you came to the answer so that I may use the same method in future endeavors with different angles and distances. Also, just how much pressure would be required to launch a potato and achieve that speed, and to what specifications would the launcher need to be built i.e. how large the gas chamber will need to be, length of barrel, etc...

Posted by mike714 9 years ago


What to do with metal tin?

So theres this broken (battery dead) executive calculator thing lying around my house. I'm not really interested in the calculator.(Anything worth salvaging?) But it was held in a nice thin silver metal box. Measurements are.. Length 9 cm Width 6 cm Depth 0.9 cm As you can see from images there is a hole where the battery would have been changed from on one side of the box. Can anyone think of anything fun I could do with this?

Posted by Turbo427 9 years ago


When do instructables appear in the search results

How long does it take for instructables to appear in the search results? Also how often are the 'views' calculated?

Posted by tim_n 8 years ago


Read others Mind!

Lets start quickly without taking much of your time.... 1. Keep a simple +ve and non-zero number in mind, example 3, 45, 79 or anything 2. Add 2 to that number, Feel free to use a pen, paper and computer calculator 3. multiply by two 4. add 10 5. add 20 6. devide by two 7. substract 15 8. substract the original number you had in step 1 9. add 6 10. multiply by 5 11. add 59 12. NOW THE RESULT OF all your calculation is 99, is that right?

Posted by avinash 11 years ago


Calculating Pi using simple JavaScript

One day I was bored and wanted to calculate Pi for myself. After finding out the Leibniz formula for Pi. When it is solved for Pi one gets: Pi=4/1-4/3+4/5-4/7... And so on since it's an infinite series. Since one can see a pattern that can easily be defined I concluded that a simple program using a loop could be made. I decided on using JavaScript for its ease of use and use a for loop. The program I made at first was mainly: var Pi=0; var n=1; for (i=0;i<=1000;i++) { Pi=Pi+(4/n) n=n+2 Pi=Pi-(4/n) n=n+2 } Where the variable "Pi" is the value of Pi, "i" is the number of times the loop is repeated, and "n" is just a variable to help in the formula. This I however found could further simplified to: var Pi=0; var n=1; for (i=0;i<=1000;i++) { Pi=Pi+(4/n)-(4/(n+2)) n=n+4 } Of course the more times the loop is repeated, the more accurate your value of Pi gets, and while 1000 may seem like a large number, the value of Pi which it calculated is wrong after the 3rd decimal point. I've had it repeat over 100,000 times and it gets more accurate, however, remember that making the number of repeats can slow down and even crash your browser (I speak from experience). If you want some ready made scripting, then here's some scripting I've made which lets you easily control the amount of loop repeats. It is based as an HTML document: //Made by Masterdude var c=0; function Calculate() { var c=prompt("Enter number of cycles:","0"); if (c>0) { var Pi=0; var n=1; for (i=0;i<=c;i++) { Pi=Pi+(4/n)-(4/(n+2)) n=n+4 } alert(Pi); } else { alert("Canceled or Error in input: Input must be positive."); } }

Posted by Masterdude 7 years ago


Current Consumtion by a DC Motor?

 I am asking few questions EV related, more current related. Let a consider a dc motor rated 4hp at 24v and 2hp at 12v. So is there a way to calculate ampere draw of the motor at various loads.(like no load, full load, or any load). And if we know the full load current of the dc motor then can we calculate the max load for the dc motor. Next as the dc motor is 2hp at 12v then will this value be constant or will the motor be able to produce 4hp at 12v even rather than at 24v. And will a battery eg 50ah be able to supply more then 50amp.

Posted by flyingdutchmen1659 5 years ago


How to measure Velocity/Acceleration of bicycle

I want to measure velocity or acceleration of a moving body(E.g: Car,bicycle,etc) without using a GPS module. Is it possible to calculate coordinate acceleration or velocity using an IMU.

Posted by Jonathanrjpereira 2 years ago


Help with capacitors

Hello everyone. I've seen this instrucable (https://www.instructables.com/id/ETJBV68MFMEV2ZAU7T/?ALLSTEPS) that uses a charged capacitor to light up a LED.I found this very interesting, so I started investigating what a capacitor is.So far so good and my questions are:- Can capacitors be used as replacements for batteries? I'm thinking specifically to light 1, 2 or 3 LEDs.- If so, how can I calculate the specs of a capacitors for a determined amount of LEDs.- Is it possible to calculate how much time the capacitors will keep the LEDs lit?- How can I determine if the capacitors have enough charge to light the LEDs?- Would you be kind enough to suggest a circuit to achieve any of these?Thank you.

Posted by transistor 11 years ago


Calculate magnet repulsive force?

I'm looking to make a "floating" model by insetting NdFeB rare-earth magnets with same poles facing so they repel. Now, magnet selling places specify the "pull" a magnet might have, say 1.2kg. What I would like to know is if the repel is equal in magnitude as the pull if two similar magnets are placed with same poles facing, is the force exerted 1.2kg and so I could float 1.2kg of stuff? Also, does stacking magnets double the attractive or repelling force, i.e. do two 1.2kg magnets stuck together lift 2.4kg of stuff, negating the small difference in distance of one magnet from the object? Is there a way to calculate the distance between two opposing magnets with a force applied. Does it follow the inverse cube rule? And if the stacking does work, do I also need an equal number of magnets on the other side for repelling, i.e. a stack of two 1.2kg magnets repels 2.4kg with one 1.2kg on the other side, or not? Does the magnet on the other side have to be the same force? Lots of questions but hoping someone can shed some light on this as I've not been able to find anything about it :-(

Posted by chiok 9 years ago