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Electro Tech is an online community (with over 170,000 members) who enjoy talking about and building electronic circuits, projects and gadgets. To participate you need to register. Registration is free. Click here to register now.

  • Welcome to our site! Electro Tech is an online community (with over 170,000 members) who enjoy talking about and building electronic circuits, projects and gadgets. To participate you need to register. Registration is free. Click here to register now.


  1. J

    Is it possible to add a dimmer switch to a USB LED lamp?

    I bought a USB desk lamp. It has a power switch + 2 switches to increase/decrease brightness. But these buttons are hard to press, very slow to operate, and even the darkest setting is still very bright. I'd love to add a true dimmer switch, so I can quickly turn it on and set the brightness in...
  2. R

    Help! Beginner in CodeVision AVR - How Turning On LED Based On Sensor Value?

    Hello guys, I'm a student that really new to this codevision. Today I am here to ask some problem to a professional in this field. Yesterday our teacher give us a proteus project and the code in codevision about ultrasonic sensor. and showing the sensor value on the LCD on the right. And now...
  3. A

    Second Pair of Eyes

    Hello all, this is one of my first electronic schematics and I'm trying to make sure everything looks good (electrically) before I order board and components. Another set of eyes on this to criticize and give constructive feedback would be great and point out any issues or mistakes my circuit...
  4. daniedp76

    Single Led Flasher Circuit.

    need a simple single Led flasher circuit that can operate from a 9v and 12v source. Thanks in advance.
  5. J

    How to make a tiny, thin LED flashlight?

    I'd like to stick a tiny LED onto a strip of card to make a flashlight that doubles as a bookmark, allowing me to read wherever I am! The LED can be white or red, but must be nice and bright (I may use more than one). Plus it all has to be light and thin. My electronics knowledge is poor and...
  6. B

    Will this code work propertly?

    I have 4 switches and 4 LEDs. I want to turn off the first LED with the first switch, the second one with the second switch, and so on. When I turn off the switch, LED should turn on. All switches connected to PORTA, all LEDs to PORTB. Initially, all LEDs are on. Will this code do the job...
  7. R

    LED it's not blinking at the expected rate

    Hello guys, I'm trying to make a led blink at 3 different frequencies, upon successive keypresses. My problem right now it's that it's only blinking 2 times and I don't understand why. D6 is LED, D4 is the test output. Here it's my main function: /*********************************************...
  8. D

    Advise needed for running LED lights from a powerbank

    Hello, I want to build a smartphone camera rig that has LED lights built in that run from a USB power bank. I’ve attached a basic design to give an idea of what I’m trying to achieve. I’ve got no experience with electronics, but can (and have) follow instructions for personal projects. Can...
  9. C

    Building a Rechargeable LED Lamp

    Hello Sparkies of the Internet, I am just a simple man of wood, with absolutely no experience in anything electric. I am however building a lamp for a project that I am doing as part of my course in Furniture Design and Manufacture, and I fear that I have made it slightly too complicated for...
  10. T

    Can anyone help me circuit a Tricorder?

    Hi there! I have 12x 3mm LED's: - 6x flashing - 6x static To this I have a standard slide switch and cell battery holder. My issue is this: how do I link these 14 components to one another and ensure the flashing LEDs stay flashing and the static, static? I believe that a 6V battery will...
  11. N

    Motion triggered battery powered dimmable COB LED light

    My view on life, in any field, is not to produce more but to consume less. Everybody told me this is a very eccentric weird mentality. Perhaps they are right. Nevertheless I have to build my project to make a highly efficient, extremely low drain, motion triggered 12V battery powered dimmable...
  12. 1

    Arduino ON led lights up with no USB, no Vin and no 5V power

    Hello, I am using an Arduino Uno for a soldering station project. I am powering the Arduino through USB port using a L7805 regulator and I saw that if I remove the USB power, the ON led still lights up when I am powering the soldering station. Also, the other led's are semi light up. The Vin and...
  13. K

    Circuit of the switch 12v. led-lighting

    One Bit Switcher I offer my own version of the circuit of the switch 12v. led-lighting for the kitchen based on the dual trigger of the hc74 chip. Created with EasyEDA.
  14. G

    Need build a circuit that flashes 4x

    Guys, I need some help. I need to build a circuit, that flashes a LED 4 times (only 4x, in a short time, like less than 1/2 second), every time that i click a bottom (click switch). If you can draw me a circuit that may work, I'll be grateful (cuz I'm still learning circuits).
  15. R

    Arduino gps speedometer

    Hello, I would like to build a battery powered arduino gps speedometer. In this arduino based project I would like to include a few features. -I would like it to turn on some lights when It detects that the speed is going down (if the speedometer is going at 10km per hour and slowing down I...
  16. sr13579

    How to make Grow Light with LED?

    I made a LED setup with blue and red LED that is supposed to help me with indoor planting. I used total 4 LEDs (2 Red and 2 Blue) for one pot of Portolaca flowers. But I think it is not simulating the sunlight properly. How many LEDs am I supposed to use? How should I make the connection?
  17. J

    Changing flashing LED on module to stay on - use a capacitor? Any help please?

    I'm coming from a programming background and although I'm doing more electronics recently I'm still very much learning. I'm using a bluetooth module (this one **broken link removed**) It has an LED function but it's really annoying. It blinks quickly when bluetooth is not connected, and blinks...
  18. W

    LED Drivers capacity

    Hello All, Thanks for having me in your group. Up front I am a disabled senior with no electronics experience at all and to old to learn much. I have always wanted to learn electronics design, repair, build ect. but never got the chance, I envy you guys and have a world of respect for your...
  19. V

    LED + Battery without fading

    Hello everyone, I'm searching for help since electronics are not my field of study... I'm trying to build a simple project that requires an LED with a constant light output (the LED must be wired to a coin battery cell i.e. CR2032). When reading the LUX from the LED I can see the LUX decreasing...
  20. P

    Need Help with LED power supoply and dimmer

    We are converting legacy lighted display boxes from fluorescent to LED. We have had inconsistent results depending on the power supply/dimmer and LEDs used. Our long time electrical engineer consultant sadly passed away and we are left scratching our heads. I know some LEDs require constant...
  21. O

    Need help with alterations

    This is a circuit board for an LED head light flashlight. It has a hi, low, and stobe feature. I would like to disable the strobe feature. I am an amature, please help.
  22. sr13579

    What is wrong with my transformer output?

    The thing is, I was trying to regulate a 220V-9V to 5 volt. I did it though. Everything was right.I was trying to make a dark sensor with NOT gate () The settings are good. But it wasn't working fine with the AC to DC adapter.( It is working fine with a battery like the video). The thing is...
  23. Lord_Nikon

    Help Please! 8x8 RGB LED Matrix with MAX 7219 and Arduino

    Hello all, I'm in the beginning stages of a project and am just learning how to use an Arduino Uno with a MAX7219 driver with an 8x8 LED RGB Matrix. I'm using someone's source code to just get a basic understanding of how to put all these pieces together and will then modify it as I need to...
  24. D

    Photodiode current measurements

    I am trying to build transconductance amplifier circuit to obtain values of the reverse biased photodiode (PD) current in order to estimate some of the LED characteristics. At first, I have used the scheme named “Recommended Zero Biased Circuit” from page **broken link removed** (placed at the...
  25. C

    But can an an LED do THIS?

    Non-technical guy, here. Trying to learn for a project I'm doing... A kids' nightlight. Need a low-power, surface-mount LED with three color settings and a fourth setting that cycles smoothly through the color spectrum. I ALSO need to be able to dim and brighten. Can anyone point me in the...

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