Questions about relays

I am building a robot with a specific purpose and I have hit a snag. My remote controls on the receiver end are 4.5v and the motors I want to run are 12v all of it is DC. The relays I have don't pull in a 4.5v so I need another way to doing this. I either need another way of pulling in the relays; I need relays that pull in at 4.5, or some other intelligent solution that I cannot think of. Please help!

Posted by kendallickes 9 years ago

Looking for relay

I have been looking for a relay that will switch with .3 vdc.  The other side is just a 9vdc source but the trigger has to be .3vdc or lower. thanks

Posted by zuben 8 years ago

Relay Schematic

I have a 1 volt signal that I need to latch open a 12 volt circuit for about a minute. Does anyone have a schematic?  

Posted by Divet 6 years ago

Arduino Uno Relay circuit

I am currently involved in a project that requires me to run a fan heater through coding in an arduino. I have decided to use a relay to act as a switch, to maintain the time period of heater running. I am using a DOAT 5V 20mA relay. I was wondering if anyone could help me with the circuit needed using a n-p-n transistor to power it while maintaining switch function. I know a circuit similar to the one below is needed, but im not sure about the capacitor and resistance values needed for a 5v, 20mA relay.

Posted by RoshanC1 3 years ago

5v relay module with tv usb

Hello there! I'm sorry if someone already asked this question but I can't find it! I would like to connect 2m led strip to my tv usb so it turns on and off with tv. Can I use this kind of relay (;=item5b016763a7 ) to do it?  Thank you in advance!

Posted by tosho82 4 years ago

switch to control dc when ac is turned on?

Hi i've got a arduino project on the go and when my arduino switches on a relay to operate a 240v ac motor, i also want it to turn on 24vdc motor. I know i could just use another relay but i'm not wanting to power the relays separately, just want to power the aurduino, and yes the board might be able to power two relays but it's pushing the limits i think.  I'm not to sure if this is called a reed switch or even if there is something like what i am after available?  

Posted by JonathanM221 2 years ago

relay from USB to turn on exrernal HDD

I found this very interesting forum yesterday, while searching for a way to jump a PSU, to work without the motherboard. I found the answer, then I spent the rest of the night, browsing the forum. I have an idea, but my knowledge of electricity, is very limited. I recently bought an old iMac G3, to tinker with. I have a 160 Gb sata HDD, connected with USB, powered with a PSU, from a dead Dell PC. I want to have the external PSU switched on, using the PS_ON# (green wire) to the COM (black wire), with a USB from the iMac, with a 5 volt relay. I'm looking for any advice, before I do this. I have a little understanding on how relays work (from automotive), but advice about resistors, if any are needed, please be very specific. I did a search, and didn't see any instructable that has been written on this. If this works out, I might try.

Posted by stroked 7 years ago

Consistent output with arduino

Hi guys! I have a little project that i could use some help with. I am quite new to the arduino, and not that steady in the code, but im hoping on getting there! The project im building is a litte controller that drives a relay output. The controller is connected to a photo-cell that has a two pin output. This output is shorted at various times depending on the movement in front of the photocell. What i need is for the arduino to close the relay for the same period (say 0,5s) each time the photocell circut is closed. And maybe block a repeating signal from the photocell within 0,5s Is this possible in some way? Any help much appreciated!

Posted by maceide 5 years ago

computer controlled relay

I want to build a SIMPLE computer controlled relay. Not where u have the relay that is on when the computer is on, the kind where u have a program that has little buttons that u click to activate a relay. Please help me!!!!!

Posted by sci4me 8 years ago

Transistor relay with NO and NC?

Does anyone know how to make a solid state relay with a NO contact and a NC?Does anyone have a schematic?Thanks.

Posted by thermoelectric 9 years ago

Build a 3v Relay Module

Would love a 3v relay module that can be drive by PIRs that output 3v signal.  Thought I finally found what I needed on Ebay, but discovered this is a bogus product that actually needs 5v to be driven. Buyer Beware. Advertised relay PCB as 3v relay. While the relay on the board may trigger independently with only 3 volts, the circuitry of the board demands a higher voltage to trigger the relay. Relay PCB has a EL817 opto-coupler for the input signal, it requires a 5V drive voltage on the Input in order to drive the onboard transistor which controls the relay coil current. With only a 3v drive, there is insufficient current to drive the opto and transistor. The module that the relay is mounted to is falsely advertised as 3.0V because the components on the board need more than 3 volts. In order to drive this relay with a 3v signal device, voltage level shifting needs to take place between 3v device and relay PCB.

Posted by DiyWaterDog 2 years ago

Need help finding a relay

My school's building a biodiesel-hybrid car. Is there something like a normally closed relay that can be opened when the voltage goes over 165V. What should I be looking at?

Posted by agent 7 years ago

What kinda relay do I use to close a circuit when a siren goes off?

I bought some of these and would like to wire up a usb gamepad to detect the siren as a button press. I'd assume this should be very simple the relay will connect to the siren speaker. I can then write an app to email/text message me if the sensor detects water on my kitchen floors.I'd like to know what kind of relay to use (how much power, an exact one would be nice), I just need a momentary circuit close (similar to pressing a key).I'm a programmer with a limited knowledge on circuits.

Posted by sylentmode 9 years ago

Home made energy saver

First of all sorry for my English Its just an idea, like that "Intelligent Power Strip" but on the cheap. Use a relay powered from the PC molex (5v yellow-black), so that when you turn off your computer, it turns off, for example, the sound system, modem... connected to this. I have no experience with relays or high voltage. Anybody interested?

Posted by javo. 10 years ago

Will a SSR work with a PWM signal?

Hey guys gotta quick question: I need to be able to cut a PWM signal from a motor for a project. I'm currently using mechanical relays but I'm curious, will a solid state relay work? I know there are easier ways to do this but for right now I'm on a clock and I just want to  know whether a SSR will work for cutting a PWM signal.  Thanks guys!

Posted by HavocRC 1 year ago

Bluetooth relay to control water pumps, lights, etc

Is there an inexpensive way to control a water pump or light or other device needing only to turn on and off by using bluetooth?  What I see in my either a computer or tablet having a bluetooth sender - either built in or a usb dongle...and, for example, an aquarium water pump with a 3.7 or 5 v relay to turn it on and off coupled with a bluetooth receiver.  The computer or tablet would have an app to control the device - with timer software.  I have seen bt dongles that can be purchased for as little as $2 in bulk...low voltage relays also for cheap.  I envision a "box" about 1cm by 3 cm by 3 cm that a pump or a light could be wired into and costing about $US 5 to make.

Posted by haopengyou 5 years ago

Can anyone identify this part for me...?

Can anyone identify this component for me?  I believe that it's a cradle relay and it is part of a really old lighting system.  I need to replace it but there are no part numbers or anything!  Thanks in advance!

Posted by mousetroy 7 years ago

DIY garage opener circuit

Hi, i was thinking of how to make my own garage door opener circuit. To make it simple, im just using a DC motor for my gates and powering using relay.. Any idea on the circuitries??

Posted by dck 7 years ago

Automotive Power Loss Annunciator

The photo shows what I'm dealing with: a sound module ($2.50 including shipping from China) and an automotive auxiliary power cord (cigarette lighter.) The sound module has a "play" button at the end of the yellow wires. The "black box" has two tasks:                 - detect loss of power on the 12V cord                 - momentarily connect the two yellow wires (as if the button switch had been pressed.) So far I’ve been told that some sort of relay and a timer could be involved, but since I’m not a Electrical Engineer, I don’t know the specifics. I know that in the automotive world, there are big, bulky relays, but I'm wondering if there are relays in the integrated circuit world? I really need specifics like part numbers and circuit diagrams. Thanking you in advance for your help.

Posted by willy41 4 years ago

help with a transistor circuit that acts like a latching relay

Hello all,, I just joined and this is my first post even though I have lurked here for some time. Now my question. I am trying to build a circuit that behaves like a latching relay. I can build a latching relay from ordinary spdt relays, however im working on a project that is going to require several of them and size is an issue. Im pretty sure a few transistors will do what I want and im sure I could figure it out on my own. I just figured I would ask here to see what kind of answers I get. I don't want any arduio stuff or microcontrollers.. My goal is to keep it as simple as possible and completely solid state and electromechanical.. basically I need it to be triggered by a negative pulse and stay on until a different negative pulse is sent to turn it off.. If possible I want to work into the circuit an adjustable output, either - or + so I can just set it to suite my purpose. It wont need to handle much current, I can add relays to the circuit to handle the higher current stuff.. I have basic to moderate experience and knowledge with electronics so I can understand some terms, but please keep it worded as plain as possible.   Thank You...

Posted by aclark32 4 years ago

dc motor with limit switches wireing help

I have a 1998 Trans am that has power windows. The problem is the doors are fiber glass and the motors create a lot of force on the doors creating problems. What I want to do is put a limit switch at the top and bottom of the window travel.        I'm using the factory switch that sends +12 volts in the up or down direction   I have a dc motor, limit switches and dpdt relays. I need to know how to wire it all together. If you could draw a picture that shows all wires from switch to relays to micro switches to motor that would be best. Thank you for your help     E mail

Posted by 123COOPER 3 years ago

300 AMP SCR for sale

I have a 300 amp 1KV SCR I am saleing it for $25 shpping is $6 for in the USA

Posted by inductionheat! 8 years ago

Use Arduino to switch AC load while using the same outlet to power the arduino

Hey guys, So basically I want to control an AC load about 3 amps at 120 VAC plugged into a regular outlet via an android phone.  So Im thinking of having a pass through outlet that I will switch with a relay and an Arduino, however I also need to power the Arduino with the same outlet, a battery isnt very viable because Im going to have a Bluetooth module also. My question is what is a safe way to do this, how do I avoid feedback voltage when the AC load when it turns on? Will having the AC/DC Arduino converter in parallel with the AC relay okay?  Thanks, I have done quite a few Arduino projects just not any with AC power. :)

Posted by dkoshkin 5 years ago

Motion Triggered Horns

I'm starting this one over, I made a mess of the last topic. Essentially what I'm starting with is a driveway wireless alert system (  and a car horn. The car horn is wired to a push button switch. ( What I'm trying to do is replace the [S] (switch) with this wireless trigger. The alarm speaker outputs at a very low voltage, ~0.08v: The alarm LED's output 1.75v (measured from + on the one LED and - on the other, there are three total, in series) What would be the best place to tap in to get voltage from to trigger the relay? I think from the previous post I'll need a transistor switch of some sort? This is the part I need help with. Usage: Tractor pulling hayrack riders over a bridge, I'll place the sensors ahead of the horns so by the time the tractor is at the sensor the hayrack is right at the horns. Hope I posted in the right spot. Thanks

Posted by jinstructr 4 years ago

How to add a 30 minute 110v timer into an existing wall heater?

My bathrooms are heated by in-wall electric heaters that are controlled by a rheostat type knob on the devices themselves.  I find that they often accidentally get left on for long periods of time (a safety and energy usage concern).  As such, I would like to add a timer into the existing devices that would cause them to shut off after 30 minutes (the timer would be reset by turning the heater off).  I know that they make wall switches which can accomplish this task, but due to limited wall space I would prefer to not have to wire a new switch to the heaters.  My goal is to find a small circuit board that I can add between the existing control knob and heater.  It would need to be small and heat resistant so that it could be placed inside the heater itself.  Anyway, I have been trying to find such a device online but haven't had any luck finding one that runs on 110v and can be added directly into the existing circuitry.  I was hoping someone on this site could point me in the right direction. The heaters are both tied to the same breaker and are the only things on that circuit so another option would be to place the timer near the electrical panel.  However, this seems less desirable to me as you wouldn't be able to turn on the 2nd heater if the 1st heater had been left on and already tripped the timer.  Please correct me if I'm wrong about this.

Posted by jenkins3333 4 years ago

3v Relay Module and PIR sensor circuit troubleshoot

​Looking for help on my project.  See image.  Testing before connecting to high voltage device.  Using a 3v relay triiggered by the PIR signal.  As you see wired now, There is no ground wire coming from PIR.  The circuit would not trigger relay with a ground wire to the PIR.  When this does trigger I noticed on the relay that the LED would not go completely off.  So I check to find that when relay turns "off"  the PIR is still sending 2.8 volts to the relay.  Not enough to trigger the relay, but enough to show power through the LED.  Obviously something wrong here where the PIR or Relay are still drawing power.  Can you help?

Posted by DiyWaterDog 2 years ago

Undercurrent relay

Hi, Does anyone know how to make one of these Cheers

Posted by eddcole 9 years ago

Relay Timer

I am currently engaged in a project where i need to create a count down timer relay controller. i was thinking of using a digital alarm clock as part of my goal is to have the display visually counting down, but i don't know of any that have a count down feature. i want the timer to power a relay to turn a string of IR emitters on for several seconds. i have a digital kitchen timer that counts down, but im not sure if it will work. i would like to use the power to the buzzer to activate the relay but there is no stable current there, it only Emits several beeps in quick succession(when i meter it, it comes out to about . volts). this is why the alarm clock would be better. i was hoping to use an electromechanical relay but i don't think it will work. does anyone know of another relay that will trigger with this kind of input?

Posted by gedion4000 9 years ago

Multiple Relays controlled by clock Arduino

A friend has a project in mind that involves an arduino controlling multiple relays with the use of a clock. He would like to be able to control each individual relay, and would like to be able to have a different time schedule every day of the week. There would be times where more than one relay is activated, and times when none are. How could this be done?  Could someone direct me in the direction I should be looking? Not sure what to look for here (Most of what i found only works on 24 hour loops)

Posted by RocketPenguin 2 years ago

Wireless control of a NC relay?

I'm sort of a newbie when it comes to this stuff. Originally I planned on just putting in a NC momentary switch. Now my idea has evolved, I would like a momentary switch to wirelessly control a relay. How would I go about setting up a wireless transmitter/reciever. Whether it be IR or something else.

Posted by Spamwich 7 years ago

Trying to turn on and off leds with tv usb

I have LED lights in the back of my tv ( ambilight ), but they stay on when the tv turns off . What I am trying to do is to turn off with the USB on the tv with a relay . I'm thinking if it is possible to use the 5v from the tv usb to power the relay so when the tv stars it gives power to the usb , starts the relay, that is connected to the "+" of the leds and makes the connection to turn on the lights. My question is i'm not a electronic guy and I don't know if it will damage the tv or the lights . should i use something else like a diode? This is the relay i'm using;=8-2&keywords;=songle+srd-05vdc-sl-c

Posted by pastos 8 months ago

Schematics for a one way RF Relay/Switch?

So my plan is to have a small remote with a single pushbutton that when pressed will close a relay on the reciver, I would like it to have a pretty good range of at least 1000 Meters. I thought of using XBees and Arduinos but i only need the signal one way and only a single channel. Any ideas?

Posted by tomtortoise 6 years ago

LED relay switch... maybe?

First off thanks for looking and helping if you decide to. I have only been working with computer electronic in a DIY since for about a year. My question is, do I need a relay for what I am trying accomplish and if so what kind? What I am trying to accomplish is: I have two push buttons (momentary contract switches). And I want it so that when I press the first button (orange) the first LED turns on. And when I hit the second button (blue) the first LED turns off and the second one turns on. Kind of like a toggle but only with the LEDs. The buttons are also connected to a board that is connected to my computer via USB. Which is where the power is coming from for the LEDs. I can use another source if necessary. I drew a little picture to help describe what I am trying to describe.

Posted by Foreverhex 9 years ago

how to convert negative pulse to positive

Hello.. I built a transistor scr to turn on leds in my car from my remote.. my remote uses negative pulses to turn on and off... now the problem is that the scr needs a positive pulse to turn on but it uses negative to turn off,, so turning it off isn't a problem.. Im pretty sure I can just use a transistor to do this.. here is the schematic I used to build the scr...  ... fig 75b... is there a way to modify this circuit to make the turn-on negative or just a way to use another transistor to make my negative pulse positive? I could easily use an automotive relay to do this but im trying to make this as small as possible and its still on the breadboard.. I want to get this figured out before I put it on pcb.. thanks for your help

Posted by aclark32 4 years ago

Controlling a DC motor to only do one rotation and to be triggered using limit switch.

Hi, I'm designing a mini golf hole for a festival in 3 weeks. The idea is to putt the ball in one hole and another ball to be released on another hole. I'm going to use a limit switch to as the trigger signal, but not sure how to get only one rotation on a dc motor and then to reset the trigger. I have to run the whole circuit off 12v battery's. Any and all help would be greatly appreciated. Thanks!

Posted by cmc graphics 6 years ago

need help on 555 110v timer.

Hey guys w up? i`m asking for help, i`m trying to develop (i have one, similar) a 110 v timer based on the 555 (or any other) i have seen many timers on the web but they run on 9v batt and i do not have room for the transformer , can u help me ??? all (just nothing) all i need is the electronic diagram . i need the timer to work on 110v and run two different cycles a: 90 seconds b: 180 seconds and cut the power. (untill you press the push button again) i have an electric diagram. tx so much. if you need help w something (i`ll try to help you if i can) even if you can`t help me ..ask e have nothing to loose.

Posted by scopevisions 10 years ago

Relay Logic

I have a fetish for antiquated technology. Stuff like vacuum tubes, transistors, electro mechanical devices, and of course relays used to run things. I did a few searches here on Instructables on relay logic and found nothing so I thought I'd start a forum on it.  Most of the earliest computers ran using relays. I love how they sound, clickity - clack. In a way they seem more alive to me than todays silent electronics, and dead boxes, There's just something cool about a machine that you can hear working instead of dead silence, maybe I'm just a old fashioned.  Anyway, I have a limited knowledge using relays for adders, if, and, or, gates, etc. but I'd like to learn more. I did however make a clock circuit using only relays and capacitors, and I have a video of it here... I based that circuit (after lots of pondering and experimentation) on the clock in this relay computer here. My relay clock was really unstable and would stop by itself quite a bit. I'd like to figure out how to make it more stable. Also, I'd like to do some more experiments... Anybody else have any interest in this subject? Or have any experience making small bit relay computers, or relay control systems for robots, etc? By the way here's some other cool relay run computers and stuff. Another Relay computer;=related Relay counter thing. Mechanical pong game - run on relays

Posted by bart245 8 years ago

What kind of relay do I need?

How do I find out which kind of relay switch I need for my alarm clock project (connecting an alarm clock to a motorized water gun). What information do you need? Thanks.

Posted by hthnc-student 5 years ago

solid state relays

I have four, 5A, 280V solid state relays. They are activated by 3-8V. I need to tie them together so that I end up with a total of 20A. Do I tie them in series, or parallel? Also, do I tie the inputs in series or parallel so that there is one input? Thanks.

Posted by gimmelotsarobots 8 years ago

WANTED: Bluetooth Bee to Unlock car (or anything for that matter)

I have an Arduino uno, A  relay shield with both 4 onboard relays and an Xbee socket with a Bluetooth Bee plugged in. I need the code to: What I want is to be a able to pair my phone with the Arduino, and after that whenever it detects my phone (or whatever, just a device that has been paired previously) it will do 2 things. 1 is send a low voltage, low amperage momentary ground via relay 1, and 2 send the same via relay 2 to another device (this one would be 12v) Now when it becomes Unpaired it will wait a variable amount of time (Say 20 seconds) and then send another low voltage low amperage ground pulse via relay 3, and repeat the 12V ground pulse via relay 2 again. After that it will repeat the process from the beginning.  Im willing to Pay a Modest fee for this, and afterwards Im going to make an Instructable for anyone wanting to do the same..... and the code will be made freely available for all. Thank you for your consideration.

Posted by wbarfels 6 years ago

How to find out a relay's "trigger" voltage

Hey there! I currently have several "old" (read: unused) relays laying around that I'd like to trigger using my Arduino Uno. The issue with all of them is that they've got no datasheets available or if they have, I can't tell from the sheets at what voltage the relay triggers. Since they're all quite small and perfectly fit on a standard breadboard, I don't assume they would consume more than the 5V my arduino could provide. I already checked the connections using my multimeter and there's definitely current flowing through the line it's supposed to run through when unenergized. The actual relay I'm talking about is an AZ8-1CH-24DE ( Attached is the wiring scheme that's printed onto the relay. And here's how I've wired the whole thing: 1 - +5V from Arduino (always on) 2 - LED1, which connects to arduino's GND 3 - LED2, which connects to arduino's GND 4 - arduino GND 5 - +5V from Arduino (control pulse) I've also tried switching 4 and 5 around, thinking I inverted the two pins, but whatever I do, I can't get the relay to switch from LED1 being on to LED2 being on. Would be glad if someone could help me out with this. I'm kinda new to the whole thing, but I though I understood how these things *should* work.. Also, if anyone comes to the conclusion that the relay will definitely need a higher (12V?) voltage to "trip", could you also tell me how I can control that relay from my arduino while only having my +5V pin from the arduino available? I thought about transistors, but maybe there's another way. Best regards, Philipp

Posted by Christoph680 7 years ago

Cooling Fan Timer Circuit

I'm tying to setup a 12 volt 2.5 amp injector cooling fan in a car and I want the fan to turn on for X minutes right after the ignition key is OFF. I was looking at this programmable relay -;_rd_i=B015Z2EQCU&pd;_rd_r=5202NNSP2PM3EE5DZVTA&pd;_rd_w=SKMnb&pd;_rd_wg=rJ4Td&psc;=1&refRID;=5202NNSP2PM3EE5DZVTA Here is the website for that relay with instruction manual - I'm not sure if I need another relay and hook to 87a or if there is a better circuit I can make.

Posted by pphantom 1 year ago

HELP for using SPDT relay to turn on toy

Hello All, I'm new to physical computing and have a question that's probably very easy and yet I can't figure it out. I have a doll that cries or laughs depending on which connection you make (if you press the left side it cries, right side it laughs). I want to hook it into a bread board and then control when it cries or laughs with arduino. My teacher said I need to do this using a relay (its the big black one, I believe it is a SPDT). He gave me the schematic that I've attached here. From what I know the relay has 8 pins. according to this sketch I need to connect the 2 pins furthest away (nothing near them) to a diode and 5Volts. But- what about those other 6 pins? What do they attach to? Any help would be great! Thanks

Posted by glittersauce 8 years ago

do I need to isolate a negative ion generator?

I am looking to build a negative ion generator based spark gap... I need to limit dielectric loss, and need to use 8" of small gauge wire to and from the switch to turn it on. do I need to isolate the switch electronically from the rest of the circuit? if so, would a reed relay do the trick? if I use a reed relay, could I run it from the same power source, in parallel, or do I need to isolate power sources as well? my setup will be slightly similar to the Electrifried shoe diagram below. (no, that's not the project)

Posted by gschoppe 9 years ago

Mp3 doorbell

I'm trying to hook up a relay to the wires leading to a broken door chime in a way that when the button is pressed it causes the mp3 player to play an audio clip. what I need help on is the speaker, what I would like, is to have the speaker turn on when the button is pressed and to stay on for 5 or so seconds after the button is released. How would I do that?

Posted by zx5u 6 years ago

remote actuator with momentry relay

Hi Firstly Im new to this and my electronic knowledge is very limited What im trying to do is make an actuator move up and down using a remote using a momantary action From what I understand I need and actuator (obviously), an ir remote and a power supply I have sourced a few parts (see below) just dont know how they will or if they can go together actuator: ir remote:;=item4aa6e750c8 So what i need to happen is that when i hold one of the buttons the actuator opens and when i hold the other button the actuator closes As i said im not sure how to or if these products will go together, so if not, please could you lead me to another website where i could get the products from, also not sure if i will need limit switches etc etc ps im in the uk, so a uk based site would be an advantage for me thanks pete

Posted by newbie308 7 years ago

Newby needs some help with arduino code for kids party

OK, I'm kinda new at the programming part for my projects. I was wondering if anyone can help me with (what I assume will be a simple code for a veteran) a code for arduino and maybe with a little explanation of the code. Project is simple. I have a toy laser gun shooting at a target with a photocell attached and connected to a relay. What I would like is that every time the relay switches, a counter adds the shot so I can keep score. It's for my son's 9th birthday party and I've already built the targeting range (with  Lego Movie theme) and even some servos to knock back guys down.  I just need a way to keep score.  I have some Arduino Uno's, some nanos, some trinkets, some LCDs (2X16 and 4X8) and 4X 7segment displays so I have some options for parts,but at the moment I do not have a lot of time to go through a self-learning curve to get the coding to work.  Can anyone please help?  It would be greatly appreciated. Thanks. .  

Posted by jedii72 4 years ago

Countdown Timer

Hey guys, first forum post. I have just gotten into the electronics field, and I have made a few circuits that I have read schematics from. There's something I want to make, and it's a countdown timer. This is want I want it to have: Be able to count down from at least 15 seconds and be able to change the amount of time Have some 7 segment displays Use the least amount of voltage possible (ie: not need to use the mains or some 12 volt power supply, id rather use a couple of AA's) Have a relay capable of turning on or off a light. And to be as simple as possible. Because I am rather new to this I would rather a schematic, rather than just some help on which components I need to use, because I don't know where they need to solder to where.  Thanks

Posted by ryanlg 7 years ago

Network ON/OFF Switch with Timer

Hello there, I am a network administrator and trying to create a simple device to test the alarms on our systems. Since I am not an electrician of any sort, I have an idea of what I need, but no idea of parts or names to order. Basically, I need to have a basic on/off switch with button that I can wire to a CAT5 cable. Simple enough, stops traffic at the push of a button but thats the obvious part. I also need to have some control over how long my connection times out, and after some research, I think a timer relay does that, but I can't be sure. It just needs to turn the activity back on after it goes off say between 1 second and 10 seconds off, the connection turns back on. If I can accomplish that, than I would also like to add a dimmer type device such as that of a light switch dimmer, but smaller and working with less voltage. So... Can this be done with all 3 electric devices? The closest thing I found in searching was some generic Lag Switch, but it did give me a starting idea of how to design it. I drew a simple draft of what I had in mind. Any help by some electric gooroo's would be most appreciated. Thanks! Jonathan

Posted by hannibalxlecter 10 years ago

Need an auto-off timer switch for my home-made electronic lock

Hello. I made my own (extremely basic) remote-controlled door lock a few weeks back. It consists of a couple of solenoids, a remote controlled pass-through plug socket and a shaver adapter (lol) The RF remote turns the plug socket on and the plugged-in shaver adapter carries current to the solenoids which causes them to retract so I can open the doors. I can also use the remote to turn-off the plug socket (thus releasing the solenoids, locking the door if the door is shut) But the problem is that sometimes I forget to turn the system off and the (still-retracted) solenoids get hot after 20-30 minutes, which is an obvious fire hazard. So I'm looking for a timer that will shut-off the system after a few minutes. I've seen plugs on eBay that are designed for hair straighteners and turn connected devices off after a set time, but they all operate at 30mins+ and most require you to push a button to set the countdown timer, which is just completely useless for me. I want a timer that starts as soon as it's powered-up and shuts down the solenoids after a couple of minutes if I forget to shut them down with the remote.  Any ideas where I could get such a thing? They're operating (via the shaver adapter) at 4.2VDC if that helps I've included a photo of the RC plug and shaver adapter in case I didn't explain it very well xx

Posted by daaabs 4 years ago