Tagged Questions

2
votes
6answers
98 views

Switch transistor with a low voltage and current

I'm designing a circuit that will use a combination of switches and resistors to allow a microcontroller to identify which switch was pressed based on the voltage read and perform a switch-specific ...
3
votes
4answers
108 views

Is this arduino motor driving circuit correct?

I got an Arduino Pro Micro and some parts to play with. I want to control a little 5v motor from an external power supply by using the Arduino to trigger a transistor. Like this: Is that at all ...
3
votes
2answers
121 views

arduino pulse to transistor power maximum

Hello I want to get a confirmation that what I am doing is not going to fry my Arduino Mega. The sketch I am using to send a pulse out on pin 8 to a 2n3055 that is switching 12 volts is this: ...
4
votes
2answers
108 views

what transistor should i use?

My arduino UNO can provide max 40mA and 5V and what i need to control is 2.2V 60mA. I will use 4 shift registers (74hc595) connected to arduino and each shift register output will have a transistor ...
3
votes
3answers
162 views

Turning on multiple leds with arduino using transistor

I want to be able to turn on 50 red LEDs with one pin of an Arduino. I don't want individual control, I just want to be able to turn them all on or all off. I found this example. It uses a 2N3904 ...
2
votes
2answers
198 views

leds in parallel, switched with NPN transistors

I have the following circuit designed to drive 3 PWM pins off a 3v3 Arduino Pro Mini -- one pin for each of R, G, B in this set of 5 RGB LEDs. simulate this circuit – Schematic created ...
1
vote
1answer
146 views

Having difficulties using a darlington (BD681) to drive a 12V fan from an Arduino

I'm trying to power a 12v fan using a darlington so I can control the speed from an Arduino. When I wire up as below nothing happens, even though I'm sending a PWM signal: Have I wired up the ...
1
vote
1answer
123 views

Hooking up multiple RGB LEDs while using a minimal number of PWM pins on an Arduino?

I currently have an anode RGB connected to the 11, 10, & 9 PWM pins on my arduino. However I would like to add 3 more LED's to my project, but I don't want to necessarily take up every single PWM ...
0
votes
1answer
236 views

Using a PNP transistor with Arduino to close a circuit

I have teared down a radio controller of an RC car. I'm trying to control the car with a PC through Arduino Mega 2560 Rev 3. The controller is very simple. It takes 9 V in. There is six wires to ...
0
votes
2answers
179 views

Is it possible to use an NPN transistor to control a 5V power supply from Arduino?

I am new to EE and have a question. I have an Arduino that I want to control a 5v power supply on and off. Can I use a General NPN Transistor? Requirements: The collector is supplied by 5v dc at ...
5
votes
2answers
171 views

How to process voice commands using ATmega or Arduino?

For a project I need to start my PC using voice command. I thought to made up an voice controlled system to turn on my PC. As far as I know, when I press the turn on button-2 pin's on the motherboard ...
4
votes
1answer
125 views

Voltage regulation on the high side of a Darlington array?

I'm looking to build an 3.3V Arduino Pro Mini based LED driver that drives 3 (possibly 6) super bright 10mm LEDs (R, G and B). I intend to use this 3.7V LiPo battery and these LEDs. The LEDs have the ...
1
vote
1answer
130 views

What NPN transistor should I use?

I need to control a 12v 5A (or 3A if need be) with an Arduino UNO which has 5v and 40mA. I, unfortunately don't know how to read transistor data sheets. What NPN transistor should I get for this ...
4
votes
1answer
374 views

Arduino Uno with 12V pump: transistor or optocoupler+12V relay?

I'm not a real expert in electronics but I'm going to start a new project that has completely captured me. I need to drive a 12V pump with my Arduino Uno. The pump is "Dp0102" (12V, 0.7A). To power ...
-2
votes
1answer
148 views

Design of a system to measure the speed of a falling simulated raindrop

I would like to know if using an IR emitter and a photo-transistor would do the job. Here are the specs of the photo-transistor. Also I'm using the Arduino Uno board; any tips on how to program it ...
3
votes
1answer
519 views

Using a TIP122 to control a motor

How do I control a hobbyist DC motor with a TIP122 transistor? I want to control it with the Arduino PWM pins, the power supply is 4 1.5V AA batteries connected in series giving 6v. Also, what steps ...
1
vote
1answer
164 views

Accelerometer and Transistor

Here is my program, I want to: The microcontroller, Arduino UNO R3 sends 3.3V to the sensor, Accelerometer, MMA7361 The sensor turns on and send signal to the microcontroller. When I move the sensor ...
2
votes
2answers
649 views

Driving a Fan using TIP120 to PWM from Arduino

So I have recently started my first group project, which is to design an autonomous hovercraft. We decided to drive the propulsion fans (which are rated at ~7 V and our battery runs at 12 V) using a ...
1
vote
1answer
257 views

Arduino low power consumption and multiplexer

I've got a project that uses an Arduino with the LadyAda audio shield and a multiplexer to play sounds in response to button presses. I'm planning on using a MAX667 voltage regulator which has a low ...
1
vote
2answers
338 views

5-pole, double-throw relay

I am working on an electronics project where I need a two way switch, that can be controlled using an arduino and can be soldered by hand. I tried to Google for it, but without luck. Does anyone know ...
2
votes
2answers
90 views

Maximum effective range of RG-6/U in CCTV

How long RG-6u i can use in my cctv? what's is the effective range using RG-6u?
3
votes
2answers
995 views

Driving PWM lights with parallel darlington arrays

I am building some service light arrays, which I want to operate using the Arduino's PWM outputs. This lighting is going to be powered by 5V OR 12V with a nominal current of 700mA per array. There ...
0
votes
2answers
236 views

Logistical issue with power transistor and arduino

I have a transistor which will be triggered by an arduino digital pin. When the transistor switch is closed, ~5 A is going to flow from the collector to the emitter. However, I was under the ...
0
votes
1answer
65 views

NTE2013 base inputs

I have an NTE2013 which I want to use with an Arduino. I may be driving the base pins directly off of the Arduino or perhaps off of a 74HC595. Should I use resistors between the outputs and the base ...
1
vote
1answer
220 views

Backup battery tester circuit

I am attempting to read the voltage on a backup battery on an Arduino. To that end, I used the circuit Olin Lathrop offered in answer to this question. I am powering the Arduino with 5V, and the ...
12
votes
2answers
1k views

Selecting a MOSFET for driving load from logic

I'm looking to drive a magnetic door lock from an Arduino. I've found a question about driving a solenoid from an Arduino, which includes a circuit that looks perfect for this kind of situtation: ...
4
votes
2answers
1k views

Driving Solenoids from Arduino

I was wondering what the best way to run a solenoid would be from an Arduino board. I was thinking about using a MOSFET that runs into a relay to turn on the solenoid but am not sure how to go about ...
6
votes
1answer
628 views

Confused about transistor operation

I'm trying to use a BC108A (datasheet) transistor as a switch for a 12V power supply using the 5V digital out pins on an Arduino Uno board. I have connected the collector the 12V supply, the base to ...
1
vote
2answers
886 views

Controlling an electromagnet with Arduino

I'm just starting up with electronics and looking to control an electromagnet with the Arduino. I'm wondering what hardware setup will make the most sense to use to turn the electromagnet on and off ...
2
votes
2answers
914 views

read 12V logic pin from arduino using an NPN transistor

I have an inductance sensor on a CNC machine that goes 12V high when triggered (open collector when not) . I want to read that input on my arduino who uses 5V logic. I was thinking I could just use a ...
0
votes
2answers
521 views

RGB LEDs with arduino/transistor won't dim

Why doesn't this work? I have fifteen RGB LEDs wired up with this configuration. The transistor I'm using is the MJE3055T. Are the transistor's voltage ratings (collector-base, collector-emitter) ...
3
votes
5answers
2k views

What kind of transistor do I need to amplify an Arduino's PWM outputs?

I'm planning on having 30 incandescent lightbulbs be controlled by my arduino uno on 3 channels (10 bulbs to a channel in parallel). I've used the arduino before to control a number of red, green and ...
1
vote
1answer
286 views

AC and DC supply from Arduino?

Does the Arduino Uno supply AC or DC power when connected to the computer via USB? Can we specify is we want AC or DC? I am trying to build a circuit that has a transistor but I don't currently ...
2
votes
2answers
2k views

Best way to get +5V or +12V or 0V from arduino pin

I am working on an eeprom programmer as an Arduino shield. There are two pins on my eeprom that require a 12V signal as part of the programming process. One of them is an address pin that I am also ...
1
vote
1answer
372 views

What kind of resistors do I need to use in this Canon remote switch, if it is possible at all with the P2N2222A transistor I have?

I'm a total electronics n00b set out to create an intervalometer for my Canon EOS 350D camera which seemed super simple from the outset, but I got a bit blocked with creating a switch using a ...
0
votes
3answers
1k views

how to drive 5x5 IR LEDs with 100 mA, using Arduino

I am trying to do my first Arduino project, and I would like to drive a 5x5 matrix of IR leds. I would only like to have one switched on at a time. I understand that in an array I can do it with 5 ...
2
votes
3answers
1k views

Electronic circuit switch for arduino

Is there anything I can use to replace this circuit? Its a very simple electronic switch circuit, (transistor+zener diode+resistor) The circuit is connect to a remote control, the remote control is ...
4
votes
2answers
2k views

Connecting arduino and separate power supply grounds

I am working on an arduino project that uses transistor switches to power on high power leds that are powered by a separate 24 volt power supply. My issue is that I have two different grounds, making ...
5
votes
2answers
2k views

How do I connect a relay and transistor to an Arduino?

Ok, so this is what my relay looks like. I can't figure out what pins I hook the arduino and transistor to, and what pins to hook the the other device. Please help.