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0
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0answers
29 views

cost efficient BOM for total 10x12 16 segment (1920 led) display

I've already built a few test prototype for a large(ish) 16-segment display board. I want to use a Arduino of ESP8266 to run it, with external power, and ICs for the Characters. So far, I've been ...
2
votes
0answers
10 views

Way of powering Arduino+GSM Modem+Cam off 5V powerbank

I'm trying to build a circuit, that would turn the Arduino on by a PIR sensor, take the picture by ArduCam, then transfer it onto a webserver. I got the SW site covered by now, so that is not a big ...
-6
votes
1answer
45 views

mosfet circuit without get supply mosfet on, why? [on hold]

in ckt i not give gate supply and vd=12v than vs=12v in this condition mosfet not work as switch. why this?
1
vote
3answers
135 views

Why are my relays dying?

I am using a SainSmart 5V 2-Channel Relay Module for Arduino to drive a hot plate (110V, 1000W). I plugged my Arduino VCC and GND to the VCC and GND pins of the relay board and I drive both relays ...
0
votes
1answer
66 views

How to flicker high-power LEDs with precise square or sine wave?

I need some advice regarding a setup with high-power LEDs I am currently working on. My aim: I have a set of 6 high power LEDs (http://www.roithner-laser.com/datasheets/led_highsingle/apg2c3-530.pdf) ...
0
votes
2answers
58 views

Is a relay stressed by a partial activation of the trigger?

I'm using a relay like the one in the picture, controlled by an Arduino. I basically use it for turning mechanically on/off a circuit, when i have 0 as constant output from a series of values that ...
0
votes
1answer
63 views

Controlling an Array of Motors

I am trying to measure the state of a switch on a vending machine motor (model # BC-D27/28). It has a micro switch on it that has a lead going from COM1 to NC2 when engaged and COM1 to NO3 when ...
0
votes
1answer
47 views

Is there some way to measure mains voltage with the ACS712 sensor?

Last year I went to a maker event where some guys used an ACS712 sensor with an Arduino to monitor the mains voltage and current to monitor the energy cost in the house. One thing I saw there is that ...
-3
votes
0answers
72 views

Pull-up / Pull-down resistor

I need to read a voltage from ic (like 7408 - output of the and gate) using digitalRead function. But it can not read properly. So I want to use a pull-up or pull-down resistor. IC output is sometimes ...
1
vote
1answer
42 views

Control 24VAC solenoid with arduino using a octocopuler and a Triac

Following a previous question I implemented the following schematic on my PCB. The schematic : My PCB: I have been unable to make it work, if I measure the voltage on j13 it's allways 25v, i know ...
0
votes
1answer
28 views

Charging SLA Battery

I currently have a project requiring the use of a battery. My project has to be able to run off the battery power, but when an outside source is connected, the battery should be able to charge off ...
2
votes
1answer
55 views

I2C & SPI - share clock lines?

I know mixing SPI and I2C is a bad idea, but, when using a microcontroller short on pins, is it safe to share clocks between both buses, provided both are running at bus-tolerable frequencies? In my ...
0
votes
0answers
8 views

Arduino Uno 2 I2C devices problem [migrated]

I have two I2C devices connected to an Arduino Uno: an RTC and an OBD interface (see links below). The SCL/SDA of both devices connect parallel to SCL/SDA (respectively) of the Uno. My problem: when I ...
0
votes
0answers
9 views

Arduino Fails to Program Custom NRF52, But Has Worked In Past

Background: I have a custom board that consists of two PCBs connected via a 100mm Picoblade connector. The "Aux" board has a USB port, and CP2102N Serial=>USB converter. The "Main" board has an NRF52 ...
3
votes
1answer
122 views

How To Reassign The MISO Pin?

So I have a PCB with an LCD hooked up along with a 595 shift register. Unfortunately, when I designed the board I didn't realize that the LCD library used SPI, which on the Arduino Uno is pins 13-10. ...
0
votes
1answer
39 views

Simulate Automotive Speedometer Sender

I am working on a project and I have run into a little bit of a problem. I have a speedometer gauge that I am trying to send a signal to on a bench (out of car). The way in wich the it works is ...
-4
votes
0answers
43 views

What ic an i2c or spi device use? [on hold]

What ic an i2c or spi device use?Not microcontroller.Like spi temperature sensor etc.What an SPI or i2ctemperature sensor uses a separate SPI or i2c IC inside it?I want to make some thermocouples and ...
0
votes
1answer
23 views

Mega2560 master on RS485 bus stops communicating with VFD when I add another RS485 module

I’m doing a project where I’m building a control panel for a VFD (inverter/variable frequency drive). I’m connecting the two over half duplex RS485 and use Modbus RTU. As a master I use a Arduino Mega ...
0
votes
0answers
48 views

Run Stepper motor with more torque and smoothly

I have a stepper motor and its torque curve is below. I am trying to get more torque from the motor. Therefore, I decided to setup my driver to half step. I am using an Arduino for generate the ...
0
votes
1answer
67 views

Which kind of motor is best recommended for a curtain opener?

The general idea is to build a curtain opener, using some kind of motor connected to my arduino. Which will cause the pulling-functionality... So the following options are : 1. DC motor I feel like ...
0
votes
1answer
61 views

How to detect mains outage for 12V SLA battery charger

I'm wanting to use a 12V SLA battery and off the shelf mains charger as an uninterruptible power supply for an Arduino or similar device (via an appropriate 12->5V regulator) as also described here ...
-1
votes
0answers
43 views

Very low power BLE concepts? [closed]

I'm looking to build a mast-mounted wind speed sensor. It would need to read the DCV sensor every 1/10th of a second or so. A separate device, my iPad, would connect to it over BT and read out the ...
0
votes
0answers
33 views

SIM800C not responding during call and few seconds after call

I have this board from ebay https://www.ebay.com/itm/SIM800C-Development-Board-Quad-band-GSM-GPRS-Bluetooth-Module-w-Antenna-inm/401394684387?epid=10013775885&hash=item5d74fcd1e3%3Ag%...
0
votes
0answers
14 views

Flux(or maybe soldering paste) seems to be conductive [closed]

I bought Arduino proto shield rev3 and soldered pins to the board. As i connected arduino to laptop, I saw smoke comes out underneath the pins. One pin is connected to 5V and another is to GND. ...
0
votes
1answer
38 views

Using potentiometer in two separate circuits [on hold]

I am building a circuit with Arduino to control the motion of a stepper motor. I want to use my guitar amp potentiometers to feed voltages back into the Arduino without disassembling the original ...
0
votes
2answers
73 views

Implement 7 DPDT-switches with Arduino

OK, so my problem is the following: I have a commercial box with mechanical DPDT-switches for controlling valves by changing the polarity of 2 wires per valve. The box has 7 relevant switches, which I ...
0
votes
2answers
94 views

Emulating an SD-Card with a microcontroller (or Raspberry Pi)

some background to my story to begin with: I went to a store and asked for a bluetooth fm transmitter for my car and the guy sold me something that only plays from an SD card and I didn't even bother ...
0
votes
2answers
56 views

Arduino Nano disconnecting from PC on plugging in 3.3v NRF24L01 into PCB

I've built this PCB which includes two I2C port expanders, an Arduino nano, inputs for buttons and encoders, and headers to plug in an NRF24L01 board. Currently, I just have code running to read two ...
0
votes
1answer
33 views

Can I control/read an RFID reader with an Android device or do I have to put an Arduino board between the two?

I want to develop and Android app the reads RFID tags. I am wondering if I can control the RFID reader directly with an Android device or do I have to put an Arduino board between the two. The RFID ...
0
votes
1answer
40 views

MCP23017 with NODEMCU v3 (lolin) i2c doesn't work

I want to use NodeMCU v3 with MCP23017 that has MAX6675 at the end. Everything is on circuit please see the image. MAX6675 (U3) doesn't want to work with MCP23017. First MAX6675 (U4) works perfectly ...
-1
votes
0answers
28 views

Question Regarding Arduino PID Library

I've been looking to implement a PID controller on my Arduino. I've taken a control systems class, so my first instinct was to generate a step response and approximate the system in MATLAB/Simulink ...
0
votes
1answer
37 views

Ultrasonic cleaner control with Arduino

I'm trying to build a small sized ultrasonic cleaner. I bought a couple ultrasonic transducers (ranging between 40kHz - 102kHZ and 15 - 35 watt) which I want to play around with. There are already ...
-1
votes
0answers
30 views
0
votes
1answer
71 views

Using phone camera modules to build custom cameras [on hold]

I'm working on a project and I'm trying to keep the cost down a bit by building the camera. So I'm wondering if it is possible to use a phone camera module such as this one: https://www.witrigs.com/...
0
votes
1answer
12 views

connecting 1-Wire device powers off wemo d1 mini

I have a wemos D1 Mini (an ESP8266 chip) which I am trying to connect to a 1-Wire temperature sensor. However when I plug it in the 5v or ground it seems to power off the device, this happens with or ...
0
votes
0answers
16 views

How to use many separated A4899 for controling steppers

Basically, I was seeing the diagram for the A4899, in which mentions a logic power supply(image for reference), the thing is, how would it work if I needed more than two drivers? I was worried that ...
0
votes
2answers
111 views

High-Power Switching using MOSFETs

For a project, I need a means of switching a high-current circuit between two inductors. The purpose is, each inductor serves as an electromagnet, and they are switched every 15s or so in order for ...
0
votes
1answer
40 views

Operating a 12V electric lock with arduino

I have a similar electric lock-style solenoid like this one. If we trust the manufacturer it draws between 1.2A and 2A at 12V .I'm currently using a N-Channel MOSFET 60V 30A - FQP30N06L it works just ...
1
vote
0answers
132 views

Can anyone help me get this running? (ILI9806E TFT on a teensy 3.5)

I am at one of those points where I just can't seem to see the forest for the trees. My previous experience with TFTs has been pretty much 'plug and play' using adafruit's breakout board kit and ...
0
votes
2answers
78 views

Help figuring out the interface on this bill validator?

I would like to interface this bill validator to a microcontroller (Arduino Mega). The website says it supports RS232,RS485,Optoisolated RS232 and USB interface. The one I have is currently intefaced ...
0
votes
2answers
37 views

Regulate 12v flow with a mosfet

I have an electric lock that needs 12v to stay in a lock position. It opens on 0v. I was thinking about controlling this with a MOSFET (IRFZ44N). Currently I have the following setup: The 12v power ...
0
votes
1answer
66 views

AVR programming

This question might be asked somewhere, if so all references would be appreciated. Hello, I have programmed Atmel chip Atmega32U4 through USB. It is possible because it supports USB programming. I ...
0
votes
1answer
21 views

How to configure my xbee s2c modules for communicating with arduinos + sensors?

I have two xbee module (fixed on a development board), these boards does not have a individual access pins to access xbee pins (photo included), but rather a RS232 port. As for what I have searched, ...
0
votes
5answers
75 views

Photoresistor power switch for arduino, does this look correct

edit: uploaded schematic: I am a novice, this diagram may not be correct but should convey the attempt. I want to turn-on power to an arduino microcontroller when it is dark. I white-boarded an ...
0
votes
0answers
18 views

How to change the default Slave Select pin (Digital pin 10) on Arduino UNO R3 for SPI communication? [migrated]

Currently I am working on an Arduino based project. My project require interfacing 6 servo motors and an SD card module to my Arduino UNO. The problem is that I need all the six PWM pins for six ...
4
votes
1answer
245 views

YM2612 Circuit Audio Signal Offset Voltage

I've been working on a project messing around with the YM2612 soundchip and hooking it up to a microcontroller. I'm able to drive the chip, but I'm having a little trouble with the audio part of the ...
0
votes
1answer
33 views

Enabling and disabling serial device connected to the Arduino HardwareSerial by software

I want to use the hardware serial port (pin 0 RX and 1 TX) to connect a MAX485 IC. Internally these pins are also connected to the onboard USB to serial converter microcontroller which is used to ...
1
vote
2answers
84 views

Minimum components for BJT (edit: or FET) H-Bridge applied to a small 3-6V motor controlled by Arduino

First, why did he put R3 high--alone: H-Bridge Transistor Smoking? My real question is about the minimum number of parts. I believe the minimum components for a BJT H-Bridge applied to a small 3-6V ...
0
votes
2answers
35 views

fluctuating ADC Reading for 4-20mA Pressure transducer input

I am working on one project of water pressure measurement, in which i used pressure transducer which gives me output between 4-20mA Current form. I am using one 250 ohm resistance to convert current ...
0
votes
1answer
47 views

Adafruit 3G Module sends data but don't accept it

I'm having trouble sending commands to the GSM/GPS/3G module from Adafruit. It gives me status data at bootup without any issues (takes a few seconds). The product in use is this: https://learn....