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0
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2answers
47 views

optoisolator triggered by arduino

I'm finding it difficult to understand how to read this optoisolator documentation. Here is the optoisolator: http://html.alldatasheet.com/html-pdf/92367/TOSHIBA/TLP222A-2/248/1/TLP222A-2.html The ...
0
votes
2answers
86 views

What should I expect the output of my line scanner to look like on an oscilloscope?

I'm trying to test my TSL1401R-LF line scan camera module by checking the reading on an oscilloscope. I've confirmed that my SI and CLK signal are running normally but the output looks very strange to ...
0
votes
1answer
46 views

Using a mobile phone power bank in place of AA batteries

I was looking for rechargeable batteries to power a device I was making, however the high costs of chargers and even the batteries themselves made me want to consider other alternatives. I came across ...
0
votes
0answers
17 views

nRF24L01 and ESP8266 with one Arduino Nano

I have a solid-running network using many Nano and nRF24L01 using the RF24network Library of maniacbug and TMRH20, thanks guys. Currently I am using USB-Serial to interface In/Out with PC software I ...
0
votes
2answers
31 views

Wiring up the SRD-05VDC-SL-C to an Arduino or Arduino-like microcontroller

I'm trying to wire up the SRD-05VDC-SL-C mechanical relay to a Particle Photon and/or Arduino (not the version that is on a breadboard), and am a bit confused by the datasheet. I device I am ...
1
vote
1answer
120 views

Why does the Oscilloscope show a longer period of time than my code sets?

So I'm programming a TSL1401R-LF line scan camera module that reads in a a 1 X 128 array of pixels. I've run into a problem with the accuracy of the output. Basically the camera becomes less accurate ...
2
votes
3answers
178 views

What design decisions must I make to select a suitable P-Channel MOSFET

I need a PFET with a logic level gate to trigger a power connection to a hobby servo that pulls more current than my MCU pin can handle. The requirement is simple but I'm trying to understand how to ...
1
vote
1answer
33 views

ADXL345 GY-291 weird measures

currently I am trying to connect several ADXL345 to an Arduino Nano. I followed the Sparkfun Tutorial on how to do this (https://www.sparkfun.com/tutorials/240). Long story short, I connected two ...
0
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0answers
7 views

Can I connect and control 12 Arduino's over USB/serial to my laptop? [migrated]

I have 12 arduinos, each of them controlling some simple hardware peripherals. I want to interact with all of them over 1 USB connection to my laptop, where I have a python program communicating over ...
0
votes
0answers
33 views

Using modulation/demodulation to read analog infrared signal

I try to build a rain sensor with my kid to add to our home made weather station (temperature, pressure, humidity, PM10 pollution), using IR transmitter/receiver to provide total reflection within a 5 ...
0
votes
2answers
92 views

Arduino project LCD displays gibberish when water pump is activated? [on hold]

The setup is I have connected 9v battery to motor and I have tried using mosfet and but both works fine . I used cap between vas and V can pins of LCD it solved but the values are 20 percent high than ...
0
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0answers
40 views

Populating a list of connected ATMEGAs

I'm building some switchgear. Currently building a GUI to control an unknown number of PCBs based around the infamous ATMEGA328P, via a FT232R to the UART of the MCU. The current way of populating a ...
0
votes
2answers
82 views

Battery voltage drops when connected to a motor

I was recently working on a quadcopter so I bought a pair of coreless DC motor. My intention was to use an Arduino (DIP chip) to control the speed of the DC motor (rated 3.7 V) through a transistor. ...
0
votes
5answers
116 views

Appropriate relay for water heater rated for 220VAC/1500W

I've created a complete hardware platform using a Raspberry Pi as master/controller, an Arduino nano and two RF24l01 transceivers, which should control some household electrical appliances. The ...
0
votes
1answer
40 views

How many DS18B20 temperature sensors can I connect to one bus arduino?

How many temperature sensors can I connect to one bus without losing accuracy.Can I use for example 50 sensors to one bus? Should I change the resistor when I connect too many sensors? Here is the ...
-2
votes
1answer
34 views

Input and output relation of ACS712 Hall effect current Sensor

ACS712 works by the use of the hall effect principle. When i went through the datasheet, i found out that the relation between input current and output voltage is varied largely ie. 66 mv/A to 185 mv/...
0
votes
0answers
31 views

Sensing a light object on a plane [on hold]

I'm attempting to complete a project involving a microcontroller and some sensors. I want to detect that a very light object (20 grams) is touching a place at four different points of contact. Some ...
1
vote
1answer
105 views

A question on PWM frequency of a DC motor

I'm planning to pwm-control four of the following motors by a single ArduinoUno: http://uk.rs-online.com/web/p/axial-fans/8179151/ For some reason the nearest pwm frequency I can set is 31kHz. The ...
0
votes
0answers
21 views

How to prevent Arduino Uno to change USB port [migrated]

I have an Arduino Uno connected through USB to my Ubuntu PC (one USB hub in between). I run a program that communicate through serial and use then the port ...
0
votes
0answers
23 views

How to communicate from Python to Arduino Softserial [migrated]

That is driving me nuts so I need your help. Master : PC with Ubuntu, a USB to serial converter (chipset CP2102), connected to Arduino Uno Pin 10, 11 and GND. The Arduino Uno is plugged in the same ...
0
votes
2answers
63 views

Arduino - Pulses get unstable when updating PWM duty-cycle

I'm trying to obtain stable pulse trains when adjusting the duty cycles wth an Arduino Uno board. In my actual project I need to use 4 adjustable PWM output pins at a fixed 25kHz frequency to control ...
0
votes
0answers
29 views

Bluetooth Socket connection with HM-10 [migrated]

I'm using HM-10 4.0 Bluetooth module. I have written an android app. Upon starting the app it will discover nearby bluetooth devices. If it finds my HM-10 Bluetooth module then it pairs with HM-10 ...
0
votes
3answers
65 views

my arduino is working slowly in this function [closed]

my project is designing an ECU (engine control unit ) for a formuala car with my team , and I'm using arduino , arduino is connected to 6 sensors attached to the car such as o2 sensor map , this 6 ...
-1
votes
0answers
25 views

Mirroring display content of SSD1306 OLED using Adafruit library for Arduino [closed]

I am using Adafruit Library for SSD1306 and wanted to mirror the content displayed to use the device as Heads Up Display (HUD). I tried searching online to see if I can tweak the library for ...
0
votes
2answers
108 views

Attiny85, reading analog values from PIN3, reports 654 on idle?

At first, I am not a hardware professional (starter) so be kind please. I try to reuse a DENON operation board of a DVD-player with 9 buttons with a Attiny85 Digispark clone connected to PIN3 (see ...
3
votes
2answers
117 views

A visible light communication question concerning a preamble sequence

I have a question about preamble and preamble breaker. I am implementing a simple visible light communication using arduino. I have used a Manchester encoding scheme. While I have understood that a ...
1
vote
2answers
123 views

Why does the accuracy of my camera drop when I start using no-ops as delays?

I'm using an Arduino Mega to run three TSL1401R-LF Linear Scan Cameras in parallel. I got everything working and the camera were giving me different results based on how much light was hitting them (i....
-1
votes
1answer
45 views

Connecting Cathod Commond RGB Leds in parallel with arduino

I'm just starting with arduino, and want to light up 2 RGB leds (common cathode), and just think that the only thing I nedd was connecting them in parallel, no extra parts (my mistake), then I read ...
-1
votes
0answers
31 views

Is there an open source wlan router supporting dd-wrt [closed]

My router is not working anymore and I'have two options either to buy a new one, which is not very fancy or use my PCB designing skill and to make one by myself. Is there an open source wlan router ...
-3
votes
0answers
31 views

Arduino BLE Receiver [closed]

I'm trying to develop a solution for an outdoor fair with no access to electricity. I will give each attendant an ID with an Estimote Sticker. What I'm trying to do is add a device that costs less ...
-3
votes
1answer
77 views

What are all these pins on the DS1307 RTC for?

I recently ordered a DS1307 RTC from ebay. Before, I did some research and found out that you only need 4 pins for it: Vcc, GND, SDA, and SCL. The one I got has many other pins like DS, BAT, SQ(I read ...
0
votes
2answers
64 views

Long range sensor readings in a star network with Arduino

I'm planning a project that requires me to have around a dozen temperature and humidity sensors placed around the house and the yard. These would connect to a central Arduino in the house that would ...
-6
votes
0answers
26 views

How to connect an arduino with sim300 and a seperate gps module? [migrated]

i am trying to connect an arduino with sim300 and gps module to upload data directly into a database on my localhost using gprs of the sim inserted.I am not able to interface the seperate gps and gsm ...
0
votes
0answers
38 views

Comparing PID_v1.h in Arduino to PID(z) in Simulink

I am trying to implement model-based controllers in Arduino. I have explored several control systems in Simulink and now I want to see if I can replicate those simulations in Arduino. For instance, ...
0
votes
1answer
59 views

Arduino solar panel watt meter values reading 0's

I've been building a Arduino Watt meter for the past few weeks for a solar panel, and have successfully measured voltage and current separately. However I need to know both to calculate watts but can'...
1
vote
0answers
39 views

Arduino - External Power not working properly [migrated]

I am a newbie to Arduino and created my first project. The project is using a Sharp short range sensor and a 7 seg LED board (http://embedded-lab.com/blog/new-version-of-max7219-based-4-digit-serial-...
0
votes
2answers
31 views

QRE1113 breakout with IR LED control

I'm interested in the following IR sensor breakout board with the QRE1113: https://www.sparkfun.com/products/9454 However, I would like to control the LED (on/off, PWM if possible). Should I ...
0
votes
0answers
27 views

Arduino Leonardo clone programming problem [migrated]

I have made my own Arduino Leonardo clone using the Atmega32u4 as per attached schematic. Board operates at 5V, 16MHz. Power rails are clean. I burned the Arduino bootloader onto the device as per ...
0
votes
1answer
99 views

Best way to get 5v or 12v or 0v from arduino pin [closed]

Concerning the answer to this question explained in the link "Best way to get +5V or +12V or 0V from arduino pin" I am at very basic level of electronics because I am in first semester of Electronics ...
11
votes
1answer
988 views

Weird behavior of 'soundcard' oscilloscope

This is what I did I expected a nice square wave on my soundcard oscilloscope software but I'm getting this What is happening ?
0
votes
1answer
62 views

How to connect a headphone jack to this lm386 [closed]

I would like to attach a headphone jack to this board but I'm a bit confused as to how since the jacks I find have 5 pins but this only has 2 places for the headphone cables. Thank you in advance ...
0
votes
0answers
9 views

Aruino pro mini not accepting new code [migrated]

I recently purchased an Arduino pro mini from Amazon, and a ch340g serial adaptor to program it. When I first used it, I only used the simple blink program, just editing the delays. This worked great, ...
-1
votes
2answers
110 views

Using an Arduino (If Needed) to Charge 18650 Battery [closed]

I am looking for a way to charge 18650 battery with an Arduino (If needed) as simple as possible. I have seen tutorials where you have to buy 10 diffident parts. I just want the simple (But wont ...
0
votes
3answers
77 views

Convert PWM to Analog using a DAC chip in order to emulate a Potentiometer for audio

I'm trying to control audio level/gain (from line or amplified signal) using an Arduino. I do not want to use SPI, for this project I can only use the PWM outputs, thus I do not want to use a digital ...
0
votes
0answers
39 views

Particle Electron to RS232 Serial gibberish [migrated]

I've spent all day trying to monitor serial console output of a router. I'm using an "ebay" MAX3232 RS232 to TTL converter connecting only GND, TX and RX to the Electron. Trying to simply monitor the ...
1
vote
2answers
83 views

Issues with NPN Transistors and RGB LEDs (Common Anode)

I have a question regarding the use of NPN transistors in an RGB LED (common anode) circuit connected to an Arduino Uno. I have spent the past several months developing LED color control software that ...
0
votes
2answers
132 views

Modifiying variable inside of Interrupt vector. AVR

My question is again about modifying variables inside the ISR. If the variable used only inside of ISR, I don't have to declare it as volatile, right? After some researching, I figured out that ...