### Oscillator with AND and NOT gates? Answered

Hi, I've been recently working with logic gates and that's when this struck me.If an AND gate and an inverter are hooked up as per the attached schematic, can point A function as an oscillator?Assume that the gate inputs float high. If so 1)What would be the frequencies of the oscillations if the gates used are a)CMOS b)TTL ? 2)Would the frequency change with the input voltage ? 3)Is this implemented elsewhere? Thank you for reading my question.

### how do you make a sliding iron gate roll smoother? Answered

Have a heavy iron driveway gate that has two sets of brackets fitted with 2x3 inch grooved roller bearing wheels. I have oiled and cleaned them on a regular basis, but the gate is hard to start rolling. When you do get it rolling it can rapidly develop momentum. I would like to be able to open this gate with minimal effort. My wife struggles to make the gate to start rolling. A solution would be most welcomed and appreciated.

Question by phorton70   |  last reply

### project

Can anyone help me give a simple project using logic gates...

Topic by ferdel

### Logic gate set up with basic principal of "A is I: B is I for 1 click, then O//A is O: B is I for 1 click, then O"?

I've been looking about for awhile now for a solution to this little puzzle I've managed to get myself into. I know the question may have failed to be a proper logical statement, but basically, this is what I need: When input a is on, output b will toggle on for one second, then toggle off. When input a then goes off, output b will then toggle on for one second, then off. Basically, when the input state changes, the output will go on for a second, then off. I know the opposite can be done (that is, one second input toggles a on output, or visa vers) with flip-flops, but doing this is a bit outside my realm. Any help would be fantastic! Thanks in advance!

Question by DoctorWoo   |  last reply

### Engineering, automatic gate

Hi everyone i'm building an automatic swing gate (for my project) which uses a pneumatic actuator to open it but i'm struggling to determine how the gate is going to close, as the actuator does not have a longer stroke. i only have two and half weeks left for my due date, any help would greatly be appreciated. thanks

Topic by swazelafirenze   |  last reply

### High voltage NOT gate Answered

I am creating a circuit and I need a not gate to run 20 3v 20mA LEDs. The only problem is that to run all of those LEDs (4 series circuits in parallel, if that will help) I am using 18 volts (2 9v batteries in a series). My circuit is compact (,think fitting inside an Altoids container) so a relay wouldn't work. So I need a high voltage way to make a not gate. I can read schematics if that will help you explain it, but I do need you to mention the ohms of the resistor. Thanks a million!

Question by GenAap   |  last reply

### Logic gate help

I'm attempting to build an binary calculator out of an old iphone box using LED's and such and have a wiring system set up but i need to know how to make/buy some form of "if then else" gate (i.e. if A=1 then B=1 else C=1 and if A=0 then B=0 and C=1). I would love to know if there is some kind of way to do this using transistor logic but anything that works as an "if then else" gate is welcome.

Topic by cdarcy   |  last reply

### Gate opener with bluetooth

I wish to use a raspberry pi3 to detect when a paired smartphone in a vehicle comes in range to open a sliding gate. All the gate opening electronics is in situ.What are the pros and cons of such an idea and are there any instructables already using this method. I noted an in/out board using bluetooth detection here. Also how many devices can be paired to a RP3. I have not done any programing of a RP before.Thanks Paul Andrews

Question by illinbah

### Halloween graveyard gate

Hey guys, so I'm planning a halloween party this year, and came across this prop on one of the popular halloween store's websites : http://www.spirithalloween.com/product/cemetery-entrance-clmn-sign/ Looking at it, I thought \$150? The two columns would be more than easy enough to make like that for very cheap. I just dont know how I'd go about building the 'Cemetary' sign like that (or something similar). Anyone have any experience/ideas on how to go about doing that?

Topic by ianidas   |  last reply

### What do i use for an &quot;if then else&quot; gate? Transistor logic instrucions would be best but anything that works is fine. Answered

What do i use for an "if then else" gate? Transistor logic instrucions would be best but anything that works is fine.

Question by cdarcy   |  last reply

### Transistor NAND Gate does not completely work.?

I have been trying out some logic gates using transistors and I am confused already. I have built a NAND gate using 3 2n3904 BJT's. The resistor values are aprox the values in the schematic. The Diodes are 1N4003. Vcc is 5v (~4.9v) The schematic can be found here https://www.instructables.com/id/Digital-Logic-Gates-Just-Using-Transistors/ I have everything hooked up like the schematic shows. The issue I am having is that it is not working as I would expect a nand gate to work. The truth table shows that if A and B are both Low then C is High.  If A is High and B is Low then C is High. If A and B are both High then C is Low Here is what really happens.  A Low: B Low: C High A Low: B High : C High A High: B Low : C Low (but still ON just very very dim) <=Shouldn't this still be a High state? A High: B High: C Low Does any one have any ideas as to why it is behaving like this. I have rebuilt this circuit about a dozen times now making sure I have things correct. I am stumped.

Question by atrumblood   |  last reply

### Kickstarting a card game! World Gates: TCG

Decided to do a Kickstarter for a card game I've had in mind for a few years. It was mainly just to be used as a character's ability in a comic I do but I'm like "What the hey..." and revised it a few times. I've made a demo set for myself with roughly 54 cards (currently I've made 155+ cards cause I have too much time on my hands). But it could be fun, I've posted a rulebook for the game that will be updated as time passes. Sometimes you just have to see what sticks X3 Link: World Gates: TCG

Topic by VaughnWG

### Bill Gates shared an Instructable!

Congratulations to Instructables author gallactronics for catching the attention of Bill Gates!  He posted the Solar Scare Mosquito Instructable to his facebook page!  Mosquitos are a nuisance, and they also carry deadly diseases that kill over a million people every year.  The device works by creating ripples on the surface of still water to prevent mosquitos from laying eggs, and killing larvae that has already hatched.   Go check it out and leave a comment, or build one yourself!

Topic by Danger is my middle name   |  last reply

### Plastic Baby Gate Screen

Any known source for the sturdy plastic webbing or netting typically used on baby gates ?

Topic by trueheart7a3   |  last reply

### rfid and arduin for barrier gate

I want to create a project using arduino barrier gate and RFID , as well as make use of the dc motor for driving the gate . please help me to complete this project , I have not been able to create a code arduino with RFID Thank you

### I sense... a disturbance in the Force...

Oh yeah. Bill Gates didn't go to work today.He doesn't work for Microsoft anymore....Even if you're not a Microsoft fan, you have to admit, without Mr. Gates, where would the computer industry be? Where would we be?Flash back time:Ah, yes, I remember my very first personal computer... It was a Hewlett-Packard (not an "hp" ;-) with a MONSTER-sized monitor that took up a good 3/4 of my desk, a clunky keyboard and a "ball" mouse. It was running the latest OS: Windows 95. And get this: we were the first people on our street to get this new thing called the "World Wide Web" - whatever that meant. Our Service Provider? MSN, of course! Man, with my new computer (okay, in truth, it was a hand-me-down from Dad), I was the coolest 6-year-old in kindergarten. I had it made.Yeah, MS has made a a few mistakes...*cough*Vista*cough* (doesn't that go without being said?), but Gates and his company really did shift the industry into gear, and they aren't stopping any time soon.So, gentlemen, I ask you to join me as I tip my hat to Mr. Gates. Without him, I don't know who I would be.

Topic by Labot2001   |  last reply

### gate driver for power mosfet

I am strobing columns of LEDs at high currents very quickly (100mA for each LED, for 100us) with p-channel mosfets and LED drivers. The p-channel fets that can handle that sort of current (100mA * 24 LEDs) have gate capacitances of 1000pF and up. My microcontroller can't push too much current to the gate too quickly, which would result in the mosfet losing power to slow switch (and ghosting in the LEDs). I KNOW that some sort of gate driver buffer ic exists, i just can't seem to find one. Everything I am finding is for high-voltage or high-current applications and motor-driving. I just need something that will drive my gates at 200-400mA, and since i need 9 of them, i'd like them to be cheap. I dont need any of these motor-driver ICs or 3A gate driver chips... Can anyone help me out?

Topic by samurai1200

### Logic Gate Help Needed Answered

I am building a Binary to Decimal converter and i need help making a flawless AND gate from bipolar-junction transistors. If someone could Send me a link or email me some schematics, I would greatly appreciate it. If you do email the schematics please make sure they are compatible with Eagle. I don't want to use a converter chip because it takes away the fun of the project for me. I have tried all of the common types of AND gate configurations using NPN's (C-fwd B-in E-collect, C-in B-fwd E-Base, Etc.).

Question by toast5678   |  last reply

### Gate latch/opener design?

I'm building a fence and having trouble figuring out how to do the latch for a walking/utility gate. I want the fence to be almost seamless from the outside, so with a quick glance you couldn't tell there is a gate right there; however, the gate needs to be able to be opened from the outside with a key. The problem I'm having is that all the hardware I've found for gates use padlocks, so you could only open it from one side if it's locked, and the gate won't be thick enough to use a normal door handle or deadbolt. The parameters are: Opens from inside while locked from outside Outer hardware is minimally intrusive (doesn't stand out much, preferably nothing more than a key hole.) Actual latch can be surface mounted So far the only thing I've been able to come up with is to frankenstein the key half of a deadbolt with half of a turn handle latch I found that forks like a regular door knob but can be surface mounted. The problem is that I am afraid that the spring in the handle will be too much tor just the key to turn and it will wear out quickly. I would appreciate any ideas, and will try to clarify if there's anything someone doesn't understand. Thanks, -rob

Question by siamonsez   |  last reply

### Arduino baby gate (Newbie)

Hey guys, I'm trying to learn the Arduino Uno. Actually it will show up via fed ex in 2 days. I was thinking about using it to build a an electric baby gate for the stairs. One that slides vertically and maybe opens via PIR sensor when people come downstairs. It would probably stop using some kind of switch and have a failsafe in case it closes and someone is in the way. Any kind of help would be appreciated. Thanks. P.S. I am still learning the Arduino code

Topic by troyl101   |  last reply

### How to make an electric gate?

Hi, so an office building near my work changed from physical record keeping to electronic record keeping. so they got rid of those big sliding records cabinets that were so heavy that they had to be powered by electric motors. - which I grabbed from the dumpster. the motor has a cogged wheel thing that will suit a bicycle chain perfectly, anyway moved in to a house and would like to build a sliding electric gate utilising one of these motors and this remote control unit from ebay- http://tinyurl.com/6zmm99p any one got any ideas? for safety I need to have a safety stopper thing so it doesn't crush a child when it is closing. I have limited area where I park my car so i can't have hinged gates. they have to slide along parallel behind the front fence. yeah. my house is very close to the front frence (about 7 meters) so connecting 240 volts (I'm in OzStraYa) is not a drama. The gate will be a metal frame about 1.8 meters tall and about 3 meters wide. running on a track. ideas please. or links to other DIY electric gates. thanks

Topic by altomic   |  last reply

### Problems with logic(NAND) gates? Answered

I MADE a circuit that basically detects when an IR beam  is cut using a LM741 opamp .AS shown in the schematic i've connected the output of the opamp to the  two transistors (which is a nand gate) ,so when the beam is cut the output of the transistors should be high but instead the led at the collecter of the transistor glows only brighter. should i use a nand gate in a DIP package ?also when i individually measured the output of the opamp it showed that there was constantly 1.5 v coming out i tried measuring it with both opposite polarity leads of the multimeter  ,still  it showed a 1.5 v output,why does this  happen?PLS help.i need it fast.

Question by Strontium   |  last reply

### Ideas for powering a sliding gate?

Hi All, For three years now I have been driving in and out of this gate, and each time I do I rack my brain to come up with a clever way to power it. It would be great to have it open without getting out of the car. It's pretty heavy and I have to lean on it to get it moving, but then it rolls along its track nicely. In my work I have access to water pumps, pressure tanks and plumbing fittings, so I have been leaning toward powering it hydraulically. I don't know if this would be possible using town water pressure - if at all. If anyone has any clever ideas or suggestions I would love to hear them. Cheers, cammers.

Topic by cammers   |  last reply

### Relay Logic

Topic by bart245   |  last reply

### how to make a wood fence gate?

Null

Question by arleens6

### Would this work as an XOR logic gate? Answered

Hi, I'm new to logic gates and I am wondering if this would work as (or is) a XOR logic gate.

Question by josh1324   |  last reply

### What is the best way to build a trouble free gate?

Null

Question by beapainter

### Digital or analog clock with logic gates

Hi everyone I want to help you. Our teacher wants us to do digital or analog clock only through logic gates and we have no idea please need help thank you

Question by Mehmet Ömer Ceylan

### Bill Gates actually used Firefox!?

On wikipedia, specifically on the firefox article, response from microsoft section, the second sentence says that "Microsoft Chairman Bill Gates has used Firefox"this sentence proves that firefox is better than IE7 any daylink

Topic by coolz   |  last reply

### photoresistor + entrance gate(count people)

Hi,i would like to have something like a photoresistor (or photo cell) on entrance gates to count those passing through. i have so many gates,how do i connect so many sensors to one computer? can i recieve such signals from rj45(ethernet) ? regards

Topic by xploit   |  last reply

### SMPS failure, the Gates of the MOSFETs exploded?????? Answered

I've just build an SMPS using a TL494 chip using the power circuit from this circuit from uzzors2k, it's just a standard half bridge in my case using IRFP460's. The MOSFETs are driven through a small transformer that itself is driven with a H-bridge.  Yesterday I was trying it's first mains power test slowly ramping up the voltage with a variac when at about 180VAC i could hear some fizzling from the circuit and at 200V the GATE's of the MOSFET's exploded violently, at close inspection there was no shorts or flashovers and the gates were the only thing that was damaged at all. One thing i noticed later was the output waveform of the power transformer, unlike the signal waveform it didnt exhibit the same 96% duty cycle but a 100% with a lot of ringing on the rising peaks of the square wave, i know this can probably be fixed by reducing the duty cycle but i cant see how it could've blew up the gates. I've included some pictures so you can see what i mean by explode, as you can see on the left Fet the gate pin has completely blown off and the copper has melted slightly and the right image the same happened but i cracked the Fet open with a hammer to see if there were any clues inside. I really dont have a clue why this happened and would appreciate some help, thanks in advance.

### Automated Delivery Gate Image Capture

Hi everyone, I wanted to see if you guys can give me some advice or point me in the right direction (preferably towards an instructable) to achive my goal.  I am trying to improve upon an access gate. Currently It just opens with a remote controller. The improvements I want to implement are the following: 1. Place cameras to automatically take pictures of the vehicle as soon as it arrives from all angels     I was thinking maybe with an IR sensor of some sort 2. send those images to an email or to a database. 3. have the driver be able to scan documents and upload them to the database or send to an email, and be alerted when they have done so.  I want something like they have at the border checkpoints with those cameras, and also with the document upload. Any feedback is welcome. thank you!

Topic by glomb   |  last reply

### prizefight: bill gates vs. steve jobs

They made bill gates and steve jobs fight in this videothe cut scenes are funny and the rounds are double that of the regulars

Topic by coolz

### I need to find a way to on/off a motor automatically after about 5-7 seconds. Is it possible to do this ? help needed !

Question by rukesh   |  last reply

### Learning Redstone

I'm here today to teach you how to have fun with Redstone, now if you don't, you may just jump into a Minecraft sand well and drown. Okay, first thing is first, the BASICS. You may already know that there are what we call 'Logic Gates' in all forms of machines from a computer to a simple on and off switch. We are going to be talking about the main logic gates for now. So let's get started. The NOT Gate: The NOT Gate is what I think is the easiest logic gate to comprehend in Minecraft. It is basically an inverter. It inverts the input. For example, if I were to take an input of Redstone that is on, it would invert it and give an output of Redstone that is off.If it were off, it would be an output of on. This is one of the most used Redstone logic gates. The OR Gate: The OR Gate is also VERY simple to understand, and is also called a Universal Logic Gate, this is because you can use this gate to make any other gate existent. OR basically means 'One input OR the other input  OR both will give us an output'. This is like saying 'Jeff's dog will get a treat if he jumps in the air OR he rolls over, OR does both'. This is also easy to comprehend. (The NOR Gate is the same as the OR Gate except its output is inverted) The AND Gate: The AND Gate reciprocates the OR gate except for one major difference. Instead of 'If one OR the other is on the output is on', it is 'If one AND the other are on the output is on, otherwise it is off'. So what this is saying is that you need to have BOTH inputs on in order to have the output on. This is like saying 'Jeff needs to turn the handle AND push the door to open it'. (The NAND Gate is the same as an AND Gate except its output is inverted, the NAND Gate is also a universal gate) The XOR Gate: The XOR Gate is also very similar to the OR gate but instead of 'One or the other or both', it is 'One or the other'. XOR means 'Exclusive OR', meaning only one of the inputs can be on or else I wont turn on. This is very important when dealing with Redstone calculators or ALUs. It is one of the main functions of a Redstone Adder or Subtractor. (The XNOR Gate is the same as an XOR Gate but its output is inverted) Those are all of the main basic logic gates I'm going to take you through today! These ones are the most important ones to be used and can help people a lot. There are PLENTY more to go through but that would be a bit much documentation for me to handle. If you need any help or need some easy visuals, you can go to StephennJF's YouTube page, or you can also go to bennyscube's YouTube page for help too.

Topic by knexpert1700   |  last reply

### can anyone think of a way of making a automatic farm gate opener?

The gate must be practical for a working farm, the gate needs to be remote controlled but switched off at night this can be done  manual. a barrel would work but there are some electricity lines close to the gate. the gate needs to be wide enough for articulated lorries to maneuver.

Question by willow20   |  last reply

### hi does anybody know how to make an automatic gate motor

im looking to make them for the gates of my house like the ones you see built into the ground and work by a ram and can be used with a fob i would love a set but there very expensive

Question by daithi55   |  last reply

### What is the simplest yet reliable inverter (NOT) gate setup?

What is the simplest yet reliable inverter (NOT) gate setup, in your opinion, for feeding its output to a 555 timer's trigger input?

Question by raftor   |  last reply

### Need help to design mechanical mechanism

Hello everyone, I want to create feeder cart with seperate section, that will be hangin on rails.  Feeder cart will have four positions: First one (First load) will be bottom gates closed, middle gates open to the top. Second (Second load) will  be bottom gates closed, middle gates have to be locked in horizontal position. Third  position (First unload) bottom gates open, middle gates have stay locked. Fourth position (Second unload) bottom gates open and middle gates also open, that stuff drops out. I want ask you advice how to design bottom and middle gates open, closing and locking mechanical mechanism (without any electronical parts). This feeder cart will be operating by one man.  I have created middle gates mechanism, but maybe you have better solution.  I really appreciate for any ideas. Sorry for my english mistakes. English is not my native language. Link to my feeder cart design:  https://cad.onshape.com/documents/9bf2057d221de0e07143093b/w/42b5cff40a9a1fb3bed3cb14/e/cbc213062709ad380b4cb17b

Topic by DonatasD4   |  last reply

### DRIVEWAY OBSERVATION & SIGNAL plus GATE OPENER

We have a hidden driveway into our rental property, blocked by a large electronic gate.  Need something to detect a vehicle in the drive (either a motion sensor or a touchpad type thing?) that will make, for example, a doorbell ring in the house, and a viewing camera that can handle tropical rains, that will show up on something like a baby monitor inside the home.  The gate has two remotes, rather cumbersome and easily misplaced.  We would prefer to keep these in the two vehicles and have a button or three in the house and garage, to enable us to activate the gate opening without having to go get the remote from the car.  I would like some ideas, plans etc as although I have some electronics knowledge I need someone who has perhaps already built something like this. Any ideas, anyone?

Topic by Island-itis   |  last reply

### Mechanical Logic Gates, got some of your own design?

ADHD version at the bottom =========================================== I've been fascinated by logic gates and how they're used for quite a while now, and then I thought, "why not mechanical logic gates?". After a few brief searches on trusty ol' Google, there aren't exactly "a lot" of sources from which to draw from. I've designed a few (rudimentary) mechanical logic components myself, such as an AND gate and an OR gate (I was gonna do a negated IMPLIES gate, but I came up with the idea during Biology class, so that's pretty much gone now). The thing with electronic logic gates is that they are standardized (kinda), which makes building logic circuits easy, because you wouldn't have to build hundreds of different designs of the same logic gate just for that circuit, alone. Maybe some of you have some logic gate designs to share? Maybe we could standardize some mechanical logic gates and someone might just make a cardboard computer out of 'em :D Just to add, I am aware of the usage of weights, balls, gears, linkages, and lever-type systems for mechanical logic. We can come up with a few for each type, I guess. (this excludes fluidics, the use of water and/or air for logical computation) Yes, I have searched instructables, but even then, not a lot of sources (though some are quite fantastic, might I add). ============================================= ADHD version: Got some ideas for mechanical logic gates? Maybe we can standardize them, somehow :D

Topic by nutsandbolts_64   |  last reply

### Need Advise on Building Large Arch Gate

I am trying to make a large arch-like gate out of foam. It would be about 8' high, it would have to stand on its own, it would have to be able to be broken apart into pieces and needs to be able to last in the elements. I was thinking of buying wet foam blocks (foam used by florists) and binding sets of them together and using spray foam to cover the outsides and paint it grey to make it look like rocks. It would be held together with dowels through each set of foam and have an anchor at the bottom using dowels hammered into the ground.  Inspiration for this design came from the vault from the Borderlands game series  http://i.imgur.com/DwMSsWb.jpg I wanted to know if anyone has seen guides for making a fake stone arch or if anyone had ideas for making this (Especially if the ideas aren't too expensive) Thanks

Topic by BenH18   |  last reply

### Hi Anyone out there recognise Dual Gate Mosfet E1819. I need the pinouts Answered

Question by RayRMBC   |  last reply

### Controlling two servos with one pin and a NOT-gate

Here's an interesting idea. It may be possible to control two servos independently with only one output pin and an inverter/NOT-gate. Normally, a servo is at its 'center' position when a pulse is 1.5 ms & its angle (or speed for continuous servos) is based on the difference between the length of time of the pulse it received & the base-time of 1.5ms. The servo itself does not react to the time BETWEEN pulses however. If the signal was inverted, the result would be a pulse with a time being that of the time between pulses of the initial signal. If the width of a pulse and the time between pulses can be independently controlled, then it would be possible to control one servo with the signal directly, and another servo using the inverted signal. I found something similar here [http://www.diyrc.com/reversers.htm] but it seems to be intended for 'reversing' the signal used to control one of the servos.

Topic by Michael_Everett_Feder   |  last reply

### Does this circuit work in reality?

I have a project (designed in CircuitMaker2000), i wanted to see if it works in real... (track the OUTPUT routes to the 3-inptut gate)

Question by ~CableGuy   |  last reply

### can a jfet be placed in series with a mosfet's gate and swicthed on to turn off the mosfet?

Can a jfet be placed in series with a mosfet's gate and swicthed on to turn off the mosfet? i'd like to know if this is possible because the mosfet's gate senses voltage instead of currnet. I'm working on a schematic and its for a charge controller

Question by josh1001   |  last reply

### hello Sir i need vpn server how i gate?

I need vpn server like this http://www.vpnsell.com/

Question by khrshimul   |  last reply

### We need to alter our chicken house gate to allow chickens to pass through but not wild birds. Answered

We have covered the whole structure with bird-netting to keep wild birds out of the chickens' food, with some of it draped over the gate opening to within about 30cm of the ground.  We need to be able to get in and out of the full-height gate easily ourselves, as well as allowing the chickens to go in and out freely.  The trick is how to do that without allowing wild birds to also pass through. I thought of leaving the netting draped over most of the open gateway (we shut the inwards opening door only at night time) and then having a smaller gate at the bottom that the chickens can push through at the bottom 30cm, perhaps made of a cafe-blind cut into strips and fixed to a rod attached across the lower part of the gate. Alternatively, we could cut out some of the lowest horizontal bars of the gate and replace them with a lockable flap, hinged at the top. Any ideas of what the flap could be made of that the chickens would be able to freely pass through and wouldn't be frightened of?  I made a doggy door in another gate out of the lid of a plastic storage container but the chickens don't go through this (and I don't want them to learn how). I would appreciate any suggestions. Cheers, Mandy

Question by mandyc1965   |  last reply

### How can I hack my "RFID Vehicle Gate Pass" to give it more antenna power?

This gate pass is used to get me into my community.  I am pretty sure its whats referred to as a "Passive RFID Vehicle Transponder".  It doesn't have batteries.. therefor passive.  But the read range of the transponder is very POOR so I wanted to figure out a way to make the PASSIVE tag.. ACTIVE.  Lets say with a battery and new antenna.

Question by mmrogge   |  last reply