design help

  1. C

    What do I need to make this water-dispensing device work?

    I am trying to create a device that dispenses water. I want the device to be as cheap as possible, while still being able to dispense a specific volume of water. The amount it dispenses should be based on time if I use a 555 timer. I thought I could run a relay off of the timer so it could...
  2. I

    Design or Tools for Passthrought Voltage/Current Recorder for Batteries

    Okay so, currently wanting to set up a test for some rechargeable batteries, and developing a lower power mode for a system. The goal is to connect fully charged batteries to my devices to see how much current they actually drain. I have an estimate how long they should last, but its not exact...
  3. M

    Designing a functional function generator using op-amps

    Hello everyone, I'm currently having some trouble over a lab practice in which I was required to build an op-amp based function generator. The primary requirement is to generate square and triangle waves (varying their frequencies through potentiometers) using LM-741 IC's. Initially, our...
  4. J

    PCB Schematic design needed

    Hi, I have a PCB layout for which I need schematic design. Can someone create it?
  5. M

    MCU detect when USB is connected

    I wanted the MCU I'm using, samd21g, to detect when USB is connected on the board. The USB is used to power some other things on the board and currently isn't connected to the MCU. Also, the MCU can only handle 3.3V. I have a pin open on the MCU that I can connect the power of the USB to it...

    My first ESP32 Dev board design

    Hi everyone, I am relatively new to designing schematics and PCB's and have only ever done simple circuits up until now. I have tried my hand at designing my very first ESP32 based Dev board. I know that these can be bought for fairly cheap already, but wanted to have a go at actually designing...
  7. Swaysceptile

    How do I combine these circuits?

    We have a project coming up in my Engineering Drafting and Design class and I don't have much idea yet on how to accomplish it. We are tasked to combine different circuits to design one complete device. Then we need to of course make the Schematic (and simulate it), as well as creating the PCB...
  8. all_about_the_dip

    EMC improvements

    Greetings, I've been in a design for a while for my university. It's a security system based on sound(a glass break detector) but the point of the question is not the functionality of the circuit but the EMC issue. I've tried to reduce the EMI but I would like to ask to any expert any kind of...
  9. IgnacioMorac

    Crowbar Circuit To protect Sensor for overvoltage

    Hello partners I come to you to help me determine what resistance values or what other components I need to be able to design a crowbar circuit that protects my sensor against overvoltages. My intention is to take care of my sensor for voltages above 40V. So I started to design this crowbar...
  10. IgnacioMorac

    Protection Circuit Design for Sensor

    Hello partners The design that you are going to see next belongs to a sensor that I am building, this sensor will be capable of measuring voltages between 25-40 volts through the ADC of a microcontroller and at the same time feeding on these voltages. A fundamental part of every sensor is to...
  11. E

    Trying to design an audio circuit with a carbon single button microphone so that I can output the audio into a PC

    So I recently purchased a 285W western electric transmitter as I'm trying to more or less make a microphone that can plug into a computer which uses a carbon button microphone from the early 20th century. I have little education in circuit design, though I know enough to know I probably made...
  12. T

    Diode usage in SPI modules

    Hi All, Hoping that someone can put me out of my misery. I have been searching the internet for the past 5days for an answer to this question and feel like I am starting to lose my mind. Can anyone explain why the attached schematic has a 1N4148 on each of the SDI_5V, SCLK_5V and CS_5V lines...
  13. Y


    I need help with these questions especially the third one is a bit hard to understand for me. You don't need to solve it. Just a little explanation
  14. ThyristorWolf

    Design a Voltage Amplifier

    Hi guys.. I have to design a voltage amplifier.. The first task is to develop a voltage amplifier with an open loop voltage gain (with no attenuation due to source resistance and no loading effect) of about 10 to 15 V/mV where 1 V/mV = 1000 V/V gain. The input resistance of your amplifier should...
  15. Mooafwsa

    PCB design use with stepper motor

    I'm currently looking for a solution to a problem I have and I need to create a circuit to later develop into a PCB and these are my requirements: - I need a device to rotate a circle with 8 intervals one interval per day. - I also want a switch to reset the device once it has completed its 8...
  16. G

    Component choices and general advice for a sensor fusion device for soil quality measurement

    For a university project, I am designing and am further required to build a sensor fusion device for soil quality measurement in agricultural soil. The device will measure the volumetric water content (VWC) in the soil, the temperature of the soil and the light levels that the soil is exposed...
  17. S

    Attempting to design an automated car shade, need help with the circuitry.

    Hello! I am trying to design a car shade (the thing you put up in your windshield to block the sun) that is automatic with the press of a button. I have an idea of how it will work and the design, but I am struggling with the circuit. Here is some background: The automatic shade will be rolled...
  18. B

    Rail - to - rail opamp

    Hello, I've read something about a rail-to-rail opamp on the internet and I want to design one, just the soft part, and I am not sure if I get some things right. For example: Let's assume that my Supply Voltages are Vss = -5 V and Vdd=5 V In a rail-to-rail op amp I need my input to be anywhere...
  19. A

    Product Circuit Design

    Hi, I am currently completing a project and require assistance with the electrical circuit design. Not sure if this is where to ask but currently unsure where else i can ask and I am clueless. I have supplied information below but I may have made mistakes. The components required are: Power...
  20. Mally110

    Help, underwater 18v alarm

    Looking for some help and guidance on a personal project for my sport. I play underwater rugby, at international level, the referees in this use a cable operated buzzer system. Now this is a pain. I've designed a small(ish) remote buzzer that will remove all cables to the surface. My only issue...