15
votes
Why connect a diode between the reset pin of Arduino and 555 timer?
It's called a "Wired Or" arrangement.
The Arduino's RESET pin has a pullup resistor in it (10KΩ). That keeps the RESET pin normally HIGH. To invoke a reset that pin needs pulling low, and that is ...
- 105k
8
votes
Accepted
Why would the resistor be after the LED in this project?
It does not matter if a resistor is before or after a component, see the circuits below.
The resistor reduces the current, and this is true for the path where the resistor is in (until the ...
- 13k
6
votes
Voltage changes but digitalRead always HIGH
The problem is that when the button isn't pressed, the voltage at pin D3 is just floating. Since there is nothing attached, the voltage at the pin can be anything. To prevent this, you use a pull-down ...
- 11.3k
6
votes
Logic level converter not working?
Based on your schematic, you need to provide a 3.3v power source to the 3.3v side of the logic level converter. You can use the 3.3v pin on the Arduino.
Also, it's really hard to evaluate your ...
- 1,149
5
votes
Accepted
What is difference between analog and digital input and output, and when should i use anlog or digital (input or output)?
You will use digital pin modes when dealing with signals that are either "on" or "off", such as an LED, a switch, or another digital IC.
Analog inputs are used when you want to read the voltage ...
- 101
5
votes
Programming standalone Atmega328p-PU with NE555N timer IC
No, you won't be able to build a 16 MHz clock signal using a 555 timer. That's far beyond the 555 capabilities (see N.B.).
If you could squeeze out of the 555 a mere 1 MHz (which I seriously doubt), ...
- 2,114
5
votes
Accepted
What's in an Arduino?
You did not specify what Arduino board you are talking about. It would
have been useful to tag the question with the appropriate board name. In
the following, I assume you want something similar to an ...
- 43.9k
5
votes
Accepted
5V pin output on arduino
Time for a crash course in electronics and power:
The 5V pin only ever provides 5V. That's why it's the "5V" pin. (assuming, of course, that you give the board more than 5V).
In simple linear ...
- 105k
4
votes
Moving motion sensor?
OP didn't really specify the actual requirements other than detecting movement and wanting to use PIR while in motion.
PIR (Passive Infrared) implies looking for warm bodies. In general, PIR ...
- 1,165
4
votes
Accepted
Getting the DS18B20 detected and temperature read
Vdd on the DS18B20 is not connected to anything.
According to the datasheet:
When the DS18B20 is used in parasite power mode, the VDD pin must be connected to ground
Connect 5V from the Arduino ...
- 38.6k
4
votes
Programming standalone Atmega328p-PU with NE555N timer IC
Yes, you could use a 555. You can also go even simpler and use an RC network. Even simpler still is to use the 1MHz RC network built in to the chip.
The main drawback of these methods, and the 555 ...
- 105k
4
votes
Programming standalone Atmega328p-PU with NE555N timer IC
The default configuration of these chips, as they come from the factory,
is to use their internal 8 MHz RC oscillator downscaled at 1 MHz. So you
do not need any extra oscillator to program them.
...
- 43.9k
4
votes
Can you use an input pin instead of ground in Arduino circuitry?
An input pin can only sense the voltage that is applied to it - whether it is above or below a pair of thresholds.
In your existing circuit when the button is not pressed the voltage sensed by the ...
- 105k
4
votes
Accepted
Is it possible to increase the voltage on 3.3v output to 5v on an ESP board to power a DC motor?
You should not power a motor from a micro-controller, period, regardless if that is an ATmega or an ESP32.
Instead, you need to use a motor driver circuit - this isn't really so much about voltage ...
- 5,401
4
votes
Accepted
Does AWG size affect signal from sensors?
A signal is just a varying voltage. A wire is just a (very long) small resistor. The device reading the signal is just a current sink.
That's three terms there: voltage, resistance, and current. ...
- 105k
4
votes
Accepted
How do I know if I need to use a resistor in a circuit?
From the specifications of the sensor, you know the maximum current the sensor should be allowed to draw. Suppose you need to put 5v across the sensor.
Then write down Ohm's law: E = IR (the voltage ...
- 15.3k
4
votes
Accepted
Is this circuit risky for an Arduino Uno?
That circuit is fine as long as the input signals don't go above 12.5V. You can protect it further by adding a 5.2V zener diode across each of the signals as they enter the Arduino:
simulate this ...
- 105k
4
votes
What exactly does the return type do in a function?
It returns it to whatever the function is being assigned to.
Take the function:
int plus(int a, int b) {
return a + b;
}
That function takes two integers, adds them together, and "returns&...
- 105k
4
votes
Accepted
Best way to add external power supply when main PSU is a solar charge controller?
Should I power the Arduino with the buck converter parallel to the same PSU (the 12V 20A Solar Charge Controller) I'm using for the pumps
Yes. However I wouldn't use a 9V buck regulator, but a 5V one ...
- 105k
4
votes
Accepted
How to calculate required amperage of multiple motors?
I don't know if the amperage is additive with each additional motor
Yes, amperage is additive.
the Arduino cannot handle over one amp but 0.24*5>1
That is correct. But the stepper motors should ...
- 16.5k
4
votes
As a novice, how do I program my Atmega328p?
Are the ATMEGA and STM32 programmers not universal?
They are not the same. As far as I know their programming arrangements are completely distinct.
What programming methods can this chip support?
...
- 1,182
3
votes
Making three led's blink at different times in Arduino
Using a 220k Ohm resistor will lead to approximatively 20µA to light the LED. This is not enough to light the LED, you should replace the resitor by one of value 330Ohm (220 to 470 could be OK ...
- 201
3
votes
Programming standalone Atmega328p-PU with NE555N timer IC
It depends on how you're programming it.
If you're using a bootloader to accept programming commands via a serial connection then you will need to use the clock method specified by the fuses ...
- 17.7k
3
votes
Accepted
In the AnalogRead example, would the thing work if I remove or short the A0 and the ground pin?
I think you are confused because the ADC input measures voltage, not resistance.
To convert from resistance to voltage you need to pull in the opposite direction on the variable resistance with a ...
- 7,435
3
votes
Accepted
Powering on the PC
The two pins aren't +5V power and ground.
One of them will be what you think, the other will be a signal wire with a pull up/down.
So if the ground wire really is ground then the other wire is the ...
- 1,050
3
votes
What not to do to an Arduino
it is okay to use for simple experiments directly. But while you choose to opt for a complex tasks read the details about all the components and their wiring techniques.
specifically try to check ...
- 443
3
votes
Accepted
ESP8266 as wifi Card?
No, you can't. All you have is a UART interface through a USB to UART adaptor. It can only ever be a UART.
The best you could get would be to write a program to run on the NodeMCU that did the ...
- 105k
3
votes
Why would the resistor be after the LED in this project?
It doesn't matter where the resistor is located (before and after are meaningless concepts). What is important is that the resistor is in series with the LED.
This produces an approximation to a ...
- 1,645
3
votes
Newbie question - Biltong Box Project
Is my idea sensible and achievable (technically)?
Yep, sure is. It's not really much different to a DIY Reflow Toaster Oven.
I know that I will need a 240V relay to control the heater. Is this ...
- 105k
3
votes
For what is used an ESC with a PWM?
An ESC is an Electronic Speed Controller. It's purpose is to control the speed and direction of a Brushless DC Motor.
A Bushless DC Motor ("BLDM") is not like other motors. You can't just provide ...
- 105k
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