The Raspberry Pi is a credit-card sized computer that plugs into your TV and a keyboard. It’s a capable little PC which can be used for many of the things that your desktop PC does, like spreadsheets, word-processing and games. It also plays high-definition video. The design is based around a ...

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34 views

Reading analogue input using digital GPIO

I'm using soil hygrometer to measure soil moisture. Since I don't have adc I'm using This method. Please tell me how to connect resistor and capacitor along with amount of resistance and capacitance. ...
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1answer
64 views

Why are corresponding USB datalines connected to each other in this USB hub?

Background: this is (I think) effectively a USB hub, with built in ethernet. This is the circuit as it is being used in the Raspberry Pi B rev. 2 The USB+ from the upstream port (0) is connected to ...
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12 views

Reprogrammable Remote Power Supply Raspberry Pi Monitor and Control

I currently have a reprogrammable power supply (HCS-3400) hooked up to be controlled remotely from an control/monitor app provided by the power supply company, Manson. The supply is connected via USB ...
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0answers
24 views

Fuse header for GPIO pins?

I have recently gained interest in electronics & tinker with Arduino & Raspberry Pi. But I made some big mistakes & ended up frying my board with mains AC supplied to the GPIO :( (yes, I ...
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1answer
23 views

L293ne wireing help

First real project in many years so please accept my apologies of this is a silly question. I want to use the L293 to drive a motor (or 2). Using a raspberry pi which I have done using the add on ...
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2answers
46 views

GPIO Input fluctuating between high and low when no input is received

I posted this on the Raspberry Pi StackExchange but I feel as though it might be better suited for here, as the SE is pretty inactive anyway. I've got a fairly simple circuit that I've made where a ...
0
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1answer
29 views

Acquiring and fusing data from different controllers

TL;DR: What are some options to fuse data acquired with separate controllers? I'm developing my own IMU for a quadrotor. My inputs are an accelerometer, gyro, magnetometer, and barometer all via I2C ...
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3answers
53 views

Brown Out Problem in Raspberry Pi Over Power Tether Cable

I am in the middle of making my own ROV with six DC motors as the thrusters. The main controller inside the ROV is a microcontroller that is connected to Raspberry Pi that can send and receive ...
0
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1answer
103 views

RPI with power supply alternating between Li-ion battery pack and DC 5V

I have a Raspberry Pi model B+ and I've been trying to design a solution so that I can switch power supply without having to shutdown. The idea is this: I have 2 li-ion 18650 batteries with ...
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1answer
54 views

rasperry pi with i2c arduino leonardo

I'd like to connect a Raspberry Pi A+ with an Arduino leonardo. I'd like the rapsi to be able to upload HID sketches on the arduino.Then I'd like the arduino to run the sketch over the USB interface ...
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1answer
43 views

433Mhz Receiver Low Range Only on Raspberry Pi

I have an Arduino mini pro with a 433mhz receiver attached. I connected this to my computer via a usb to serial cable. I've tried it on two laptops ans it works fine with it (>15 metres), but when ...
0
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1answer
40 views

DIY Photobooth: LED puck lights potentiometer suggestions

I'm building a Raspberry Pi powered photobooth, and want to add some lighting. I purchased this set of led puck lights, and would love to control their intensity from the Raspberry Pi, instead of the ...
2
votes
1answer
193 views

Magic number in ADC Pi code

Im trying to measure temperature using PT100. Im using ADC Pi board for that. ADC Pi uses MCP3424(pdf datasheet) A/D converters, and in datasheet I found how to calculate voltage - it is pretty simple ...
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votes
2answers
326 views

Industrial equivalent of rapid prototyping hardware

If I want to automate something at home, I can use a Raspberry Pi or Arduino to hookup some sensors and put the business logic on the chip. Internet-of-Things-style, I can even read those sensors on ...
3
votes
3answers
678 views

how to increase the voltage of a digital signal?

I'd like my Raspberry Pi GPIO port to communicate with a digital circuit that works at 2x the GPIO voltage. The communication will be at a relatively high frequency (up to 500kHz). The main question ...
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0answers
19 views

raspberry pi A+ boot from usb [migrated]

Can RasPi A+ boot from usb? All the articles I could find only speak about booting from an SD card. Thanks, Daniel.
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0answers
15 views

Delay between bytes using py-spidev for SPI communication on Raspberry Pi [migrated]

I am attempting to read/transfer data between an instrument and Raspberry pi 2, using the RPi as the Master and instrument as the slave. The data sheet states I must have a 9 ms delay between sending ...
2
votes
2answers
72 views

Is this the behavior of a broken mosfet?

I designed this circuit to switch on/off 8 solenoid valves for a programmable dancing fountain that I am building. The GPIO is coming from a Raspberry Pi. VCC is coming from a 12V deep cycle car ...
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3answers
81 views

Power Circuit for Raspberry pi portable

I am building a hand held portable raspberry pi. I have just plugging the battery in and using the thing, but I want to make the battery completely part of the unit without the need to unplug it when ...
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2answers
240 views

How do I work out what resistor to use?

I am trying to work out what resistor to use in a circuit. The circuit is a series circuit. The power to the circuit is 5.5V, with a switch, which connects to a GPIO pin on the RasberryPi. I believe ...
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1answer
60 views

Raspberry Pi B+ with relay: Lights change but relays don't click

I am using an 8 Relay module, bought from dx.com. It has no instruction manual... This board has 8 inputs (IN1,...,IN8) to control each relay, 1 VCC pin that requires 5V and 1 GND pin. I connected ...
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1answer
26 views

Controlling an ESC for Brushless Motors with an RPi

Originally posted on Robotics, but guess it's not active enough. I'm looking to build a new (first) quadcopter without the conventional flight controller and radio, with an onboard RPi and applying ...
0
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1answer
45 views

PoE Lower Signal Voltage

I'm currently working on a little project using a Raspberry Pi and an Ag9000-S. I've got it working using Mode A (phantom power over the data pairs) and Mode B (direct power over unused pairs), but ...
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0answers
52 views

RFID race timing system using raspberry Pi?

I would like to build a race timing system using UHF RFID passive tags. I have seen self build systems described as per the following link which is being used in races with apparent success: ...
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1answer
32 views

ADC ic's for SPI protocol [closed]

I want to know what are the ADC Ic's is suitable for SPI protocol? because i cant find MCP3008 ic in shops? No one having this IC. Thanks.
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1answer
46 views

Darlington does not switch

I have a darlington Transistor circuit. Like in the schematic i attached. When i power up the 3V3 from my raspberry, the led is not on. When Doing Danke same with 12v instead of 5v, it Works ...
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1answer
58 views

DH-11 Sensor on a Raspberry Pi & Arduino

I am trying to make my DH-11 sensor work on my raspberry pi but I have not succeeded after several attempts. I followed the following tutorial from Adafruit: ...
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0answers
21 views

Creating a pulse when the circuit opened and closed [duplicate]

I would like to send wake up and halt signal to a linux board. I just want simulate the power button on the board so I will replace it with a circuit. So: When I the car's ignition line is on it has ...
0
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0answers
33 views

Can I connect my Innolux screen to Raspberry Pi 2 using TFP401 HDMI/DVI Decoder to 40-Pin TTL Breakout

Setup Raspberry Pi 2 TFP401 HDMI/DVI Decoder to 40-Pin TTL Breakout - Without Touch Innolux 5.6 LCM aSi TFT type LCD I am hoping to be able to connect the Pi2 to the Driver using a small HDMI ...
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1answer
63 views

Frequency Counting on a Raspberry PI

I am trying to count a square wave on a Raspberry PI. I tried a variety of approaches: http://abyz.co.uk/rpi/pigpio/examples.html (Freq counter 1 and 2) ...
1
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1answer
78 views

Voltage shift from 3.3V to 12V

I'd like to use MX-FS-03V 433MHz transmitter together with a Raspberry Pi (RPi). The Raspberry Pi's outputs have 3.3V, but the MX-FS-03V operates on 3.5-12V (the higher the voltage the higher the ...
0
votes
3answers
102 views

Voltage shift from 5V to 3.3V

I'd like to use MX-05V 433MHz receiver together with a Raspberry Pi. The MX-05V operates on 5V, but the Raspberry Pi's inputs only allow 3.3V. So i need to shift the RX data output level from 5V to ...
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2answers
62 views

Solderless headers?

Where can I find solderless headers suitable for a solderless breadboard.? This is for a raspberry pi project I'm working on which requires the mounting of an LCD screen. I have explored the ...
1
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2answers
165 views

Portable Batteries for the Raspberry Pi

I am building a project involving a Raspberry Pi. It is known that the RPi runs around an average of 700mA of current and my project would probably need a little over 1A of current due to attached ...
2
votes
2answers
185 views

Controlling 10 high power LED with a Raspberry Pi

I'm trying to figure out how to control 10 Luxeon Rebel LED (700mA) from a Raspberry Pi. I want to be able to turn them on and off from code, but I don't need to have two or more LEDs turned on at ...
0
votes
0answers
134 views

TC358743XBG HDMI to CSI-2 Board

I've got a project in which I have video output from a camera which I can have in either video out or HDMI out. This signal, then, is to be sent to a Raspberry Pi to be used in a computer vision ...
0
votes
1answer
75 views

Xbee Serial communication with RaspberryPi - In Lua

We are working with Mihini for an IoT project. Here we have to communicate via Xbee with sensor nodes and coordinator(RaspberryPi) . Mihini doesn't seem to have any modules particular for Xbee ...
0
votes
2answers
105 views

MCP3008 alternative

I have some analog devices like LDR, temperature sensors, and other sensors and I want to use the readings of these sensors in my raspberry pi B+ , for that I need an ADC , to convert the analog ...
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votes
1answer
71 views

Question about RFID Reader Frequency and RFID Tags

I'm researching about RFID Technology as i'm trying to build a RFID Reader using an Arduino and/or Raspberry Pi which i been trying to do so for a month however with no avail. So i been reading up as ...
2
votes
1answer
118 views

Understanding a SPI command sheet

I am interested in learning more about how SPI works in general, but with the raspberry pi and py-spidev library in mind. I am very technically savvy, although not so much on the EE side of things. I ...
3
votes
2answers
535 views

How long will a battery last based on these numbers

Hi I asked this question on SU but seemed to have gotten into a bit of trouble, I was referenced here. I am getting into doing hardware build based on things like microcontrollers and ...
0
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0answers
25 views

New Haven display On Raspberry Pi (NHD-C0220)

I'm here because I don't have experience connecting / wiring i2c devices to raspberry. I need to know how the correct way to wire this display to the gpio connector. Right now it's connected, but ...
0
votes
3answers
71 views

How does digital pullups work?

I have lame question. How does digital pullups work? I'm asking because I don't understand DHT11 driver code. Sample code: ...
1
vote
0answers
86 views

How do I connect a photodiode to a GPIO?

I'm trying to read serial data emitted through an IR led with a Raspberry Pi using an IR photodiode, but I'm not sure about the correct way to hook it up. Unfortunately I don't have a part number for ...
1
vote
1answer
80 views

Does Ground Voltage Need Lowered As Well?

I am dividing voltage of a 9V battery to 3V for a Rasperry Pi GPIO. I have the ground connected to the end of the resistors, so it is back to 9V when I connect it to the Pi's ground pin. Is it ok to ...
0
votes
0answers
83 views

Building a UPS for Raspberry-Pi

I am trying to build a 5V/2A uninterrupted power supply (UPS) for my rPi B+ using LM7805 and some phone batteries (3.8V/0.5A and 3.7V/2A) or any of the 6 pcs 18650 batteries (3.7V/2A) that I have ...
1
vote
1answer
56 views

problem with LED matrix and raspberry pi

I have a raspberry pi model B+ , and an 8x8 LED matrix(single colored) , so I connected 8 GPIO pins to the 8 row pins of the matrix and another 8 GPIO pins to the 8 colomn pins. Note that I am pretty ...
0
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3answers
88 views

(Beginner) Type of (NPN?) transistor to use for RasPi

I'm new to EE. I burned out a Raspberry Pi by running an electric motor directly from its GPIO pins, and then I learned about transistors. I now have another RasPi, but I'm not sure what transistors ...
0
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0answers
112 views

RFID card reader : wiegand 26 bits but UID tag 40 bits?

I am working on a project of access control with a Raspberry Pi. I want to buy a RFID card reader (125 khz) and tags. After a lot of research on the web, I found out that the most common connection ...
0
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0answers
30 views

What are the main differences between 4n25 and SFH6156-2T optocouplers?

I'm looking for a 4 pin surface mount equivalent to a 4n25 optocoupler. I'm really not sure what to look for when comparing the data sheets of each optocoupler and I want to try avoid purchasing the ...