12
votes
Accepted
Two batteries sharing ground?
Not only can you share the grounds - sharing the grounds is required for there to be any form of meaningful circuit for signals to get around the place.
To copy-and-paste a blog post I wrote some time ...
- 105k
11
votes
How to design and debug a custom I2C master-slave system?
This tutorial I gave at the Embedded Linux Conference tries to answer the questions, providing links to more detailed description of the topics addressed and using the practical example of driving a ...
- 2,125
10
votes
Is it possible to make normal pins act like ground pins?
No, it's not going to work - even worse, you risk frying your Arduino -, for the following reasons:
The Arduino data pins can't source (neither sink) enough current for that to work.
The inductive ...
- 2,114
9
votes
Accepted
What happens if I don't use a relay for 5V pump
You should put a resistor in series with the led to limit the current.
The IO pins cannot source enough current to run the pump without damaging themselves. That's why you need a buffer of some kind.
...
- 3,267
9
votes
Accepted
How do I (easily) power a 5 V 3-pin fan?
You are correct in your assumption that you can not power a fan from an Arduino directly.
Use a transistor, for example 2N2222 or BC548, which is switched by the Arduino, using a single pin, in order ...
- 2,880
9
votes
Accepted
Is there any better choice other than using delay() for a 6-hours delay?
Several options here, and a couple folks have pointed out some challenges.
"Best" answer -- probably to use a real-time clock (RTC) board to assist your timing, and effectively set a target ...
- 106
7
votes
Accepted
Controlling a 5V fan and ultrasonic fogger with an arduino - do I need an external power supply?
About the ultrasonic fogger:
The product description is misleading. This is a pure transducer. That means it does not generate its own ultrasonic frequency and is thus not DC. You need to provide an ...
- 15.8k
6
votes
Debugging my Stepper Motor Driver circuit
I had this same issue when setting up this circuit with this code and driver on an Arduino Uno. All else was fine, but the current for the motor was set WAY too high on the driver from the factory. ...
- 61
6
votes
Accepted
Transistor slows motor instead of turning it off
I can't make much sense of your diagram- but this is the correct way to do it:
simulate this circuit – Schematic created using CircuitLab
R1 is low enough that the base gets 10-15mA of drive,...
- 346
6
votes
How to define a SoftwareSerial object inside a class?
Personally I wouldn't go down this route. Instead I would pass a Stream object (as a pointer or a reference) to the constructor and use that. Then it is up to your sketch to define what that Stream ...
- 105k
6
votes
Newbie Arduino DC motor problem
I see a couple of issues here, which are related to your questions. I will use numbers here, but these do not necessarily correspond to the numbers you have used when asking.
The first thing you need ...
- 161
6
votes
Dshot implementation on Arduino (ESC protocol)
In short, I ended up creating a library capable to drive multiple DShot600 ESCs:
DShot-Arduino
It still need a lot more polish, but the bit-banging works really well.
SPI method
I tried the method ...
- 161
5
votes
Accepted
Arduino DC motor causes disturbance. What can cause it?
Thanks for the help everyone. I fixed it by using Capacitors. They suppress the noise that the dc motor produces. I found my information here
- 101
5
votes
Controlling a DC motor with an external power source
Seeing as you want to use a 12V battery, you should try an external motor controller. You would essentially connect the Arduino to the controller, then the external battery and motor to the controller....
- 240
5
votes
Accepted
Why is my Adafruit motor shield not spinning my motors?
A couple of things I see...
1.) Your motor leads may be shorting out of the housing of the motor. make sure they are not.
2.) You may have the motor on the wrong port for the given code:
On line 7 ...
- 66
5
votes
How to make servo rotate for angle bigger than 180°
No. The continuous rotation servo rotates continuously and you can not control where to stop. You can control the rotation direction and the speed at a little.
What you need is either a special 270 ...
- 771
5
votes
How to track revolution of DC motor?
You can Use wheel encoders. You can even make your own wheel encoders with general parts like photoTransistor and lasor or led light. you can make your encoder or print it out in paper. The use little ...
- 279
5
votes
Stopping / starting DC motor with Limit Switches and on/off button
Check your switches have pull-up resistors
It would be helpful if your question included a schematic. Do you have pullup resistors in line with your activation and limit switches? If not, you might ...
- 478
5
votes
Accepted
Why is Arduino resetting while driving motors?
The VIN pin goes to a 5V voltage regulator on the Arduino and needs at least about 7V minimum to work properly. If you want to supply 5V to an Arduino do it either on the 5V pin or via the USB ...
- 583
5
votes
declared variable inside void setup is forgotten in void loop
Yes, that is how C and C++ (and most other C-like languages) work. Variables have "scope". Any variable define inside a pair of curly braces (between a { and a }) is only visible inside those braces.
...
- 5,652
4
votes
Seeking to measure back EMF of an electric motor via Arduino
There is no need to measure the windings of the motor... please see the great write up for full details using an Arduino to sense the back EMF on a PWM driven motor to control the speed. This can be ...
- 41
4
votes
Accepted
How to eliminate noise from PWM controlled 12V fan at low speed
I had the same problem with a 5V fan. Something simple worked for me: To decrease the PWM frequency. You probably want to do this using pin 9 or 10 (for the Uno) as changing the frequencies of other ...
- 56
4
votes
Accepted
`servo.attach()` paralyzing (one) motor on L298N
The Servo library uses Timer 1 to create the servo control signal. That means it can run the servo on any pin or combination of pins, and at the 50Hz speed that a servo likes best.
However, pins 9 ...
- 105k
4
votes
Expected ')' before ';' token Error
Well, for example for doesn't have four parts but three
for (int i = 0; i ; 256; i++) // => for (int i = 0; i < 256; ++i)
Next one doesn't look much better:
for (int i = 255; i (>);= 0; ...
- 4,742
4
votes
Accepted
What are the unused pins in an Arduino L293D motor shield?
Check out this Link. Here, you can find this explanation in Code. I hope it will helpful for you.
Pin usage with the Motorshield
---------------------------------------
Analog pins: not used at all......
- 1,476
4
votes
Accepted
Why is one part of my code being executed over the part before it?
The problem is with your logic. You are saying:
If it's too close in front then move backwards
Otherwise stop all movement
If it's too close on the left then move forwards
Otherwise stop all movement....
- 105k
4
votes
Accepted
Should I use motor driver or Motor driver shield?
The right driver module or shield depends on the motor. Do you know the voltage and the stall current of the motors ?
The L293D uses bipolar transistors for the output stage inside the chip and can ...
- 3,216
4
votes
What happens if I don't use a relay for 5V pump
this is not an answer to the question you asked, but you need to understand this:
generic DC relay advice. Use commutating diodes. this is not a special kind of diode, it is a particular use of a ...
4
votes
State machine doesn't function
I don't know enough about how tapes work to comment on the sense of what you're doing, but some problems with the code:
You are reading the input and setting buttonstate once only in setup(). You ...
- 2,181
4
votes
Accepted
Motor shield leaves no pins accessible
According to tutorial, the shield uses almost all D pins. Free are pins 2 and 13. If servo is not used the pins 9 and 10 are free too. The pin 2 has the extra hole to solder a wire or a single pin ...
- 17.7k
Only top scored, non community-wiki answers of a minimum length are eligible