15

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 done from a number of sources: The RESET button The DTR pin (through a 100nF capacitor) of the USB interface chip The 555 watchdog circuit above The critical ...


8

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 interconnections before/after the resistor). In the examples there is only one path. simulate this circuit – Schematic created using CircuitLab


6

They are what is known as Pull-Up resistors. The circuit will not work if you replace them with wires. Not only that but you will short circuit the power supply when you press a button. Why don't you want to use resistors? The value is not important - you could use the same value as you are using for the LED if you don't have the 10k resistors shown in ...


6

Without an image of the display, I'll have to guess. With 12 pins in total, what you most likely have is: 8 pins for 7 segments and the decimal point, and 4 COMMON anodes or cathodes, a detail you will have to discover yourself. This process requires a power source that can safely light LEDs. A multimeter in diode test mode will do since theres usually about ...


6

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 soldering with such a shaky picture. Just make sure none of the pins are connected. A visual inspection usually will do, but if you want to be sure, use your ...


6

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 Arduino Uno, i.e. an ATmega328P at 5 V and 16 MHz. I realize I can go look up the actual design itself [...] You should. There really isn't that ...


5

The thing to remember about electrons is they are a negative charge. That means that the direction of current flow (positive charge) is opposite to the direction of flow of the actual electrons (negative charge). Picture it like those "compression jams" you get on the motorway (freeway) where cars that are travelling too close together have to slam their ...


5

Fundamentally, because the systems they were designed for convert rotary motion to linear, typically with a range substantially less than 180 degrees (probably more like 120 degrees). Next, because the control scheme of PWM position pulses is not able to convey requests over an arbitrary range - the mapping of pulse width to position must be limited, and it ...


5

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. Once you program the chip the first time, if you configure it to use an external resonator/oscillator, then you do need to have that attached in order to reprogram ...


5

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), the clock stability and jitter would be so bad that it won't be usable but for simple sketches not requiring any timing accuracy. At that point, you would be ...


4

Sorry about the crudity of my image, but you don't always need those transistors. Peter has already said so, but I wanted to explain a bit further. The only thing is that you need to set a pin to LOW to light up the led, and HIGH to turn it off. Just use a ! to make your code more intuitive if your like. So e.g. digitalWrite(segmentA, !HIGH) Some ...


4

(1) A simple method BEST method is to use a proper charger - they are not high cost if you look around and doing it properly extends precious battery life. Next best in this context is my "better" method in 2. below. BUT, given the system you say you are using now, the following very simple method will greatly improve your result and ave your battery ...


4

It is not so easy to create a -5v power supply using a capacitor or transistor. A very easy way is to use an additional Wall wart power supply to create -5 volts (while still using your original +5 volt power supply). For the additional (new -5 volts power supply), use the two wires (positive and negative to create your -5 volts). The positive lead ...


4

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 motion sensors look for the presence of thermal radiation that moves between the individual parts of the sensor. On TV it is shown that you can fool PIR detectors ...


4

You don't need to reduce the current. 2000MA (2 amps) means the power supply is CAPABLE of supplying this (without overheating). Anything less than this, and your device will work perfectly. Your Arduino will DRAW a certain number of milliamps (amps), this is the amount of current that will ACTUALLY run through your circuit.


4

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 to both DQ from the DS18B20 and Port 2 on my Arduino (the two yellow cables). That means port 2 would always be high, right? According to Temperature Sensor ...


4

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 potential of something. This is typically used to read analog sensors. Analog outputs are not really analog at all on the Arduino. Instead, the Arduino uses ...


4

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 particularly, is that of stability. Using a crystal and capacitors you can get very accurate timing at high frequencies. Using a 555 you can get ballpark timing ...


3

Quite simply put, it's a little reservoir of energy for a chip or other device to dip into when it needs to get a little extra power. In Electronics nothing happens instantly. When a chip needs more power it has to get it from the power source. The power source then has to respond to that by providing more energy, and that then has to make its way down ...


3

You can use a single resistor on the common pin if you want. The problem is that lighting up multiple segments at the same time will substantially reduce the brightness of each one. You could work around that by lighting each segment one at a time in very quick succession though. It should be possible to control the display directly from the IO pins by ...


3

The arduino website states that the operating voltage of an arduino is 7-12V. That's when it goes through the voltage regulator. It's a linear regulator, meaning it wastes a lot of power as heat. The regulator outputs 5V that's given to the MCU. The USB voltage bypasses the regulator and goes to a fuse before going to the common 5V for the board. If less ...


3

There is an article by Atmel, talking exactly about this (not for homebrewing, though). They provide a link to a PDF file that describe in detail a project involving Arduino and a re-created washing machine. Note that it seems to be some kind of Bachelor graduation project, and that the students seem to build an entire washing machine. They control the ...


3

The problem here is that you lack the concept of speed with your motors. It's not enough to turn the motors on or off in the right direction, you have to control the speed of them. Your left/right control is fine as it is (without the delay in your loop), which is controlled by the inputs being either on or off to define the flow of current through the ...


3

These types of receivers are AC coupled so you will not be able to do what you are doing as you need to have regular transitions in the signal and not stay in one state for too long. They are also limited in the speed at which they will work, I expect 19200 bps is too fast. You need to use a modulation technique such as Manchester Encoding or other ...


3

No, it would not be correct to use a single resistor to replace a potentiometer. On an LCD the potentiometer is used to adjust the bias level of the LCD - that is the contrast. You need to use it to set a voltage between Vcc and Vee, which you feed into Vo. That is, a voltage somewhere between +5V and -5V. You can't do that with one resistor. You can, ...


3

Connecting the grounds together is required since without that there would be no circuit for the current to flow through. Take this simple block diagram for instance: In the top diagram there are two complete circuits - the green one (Arduino's 5V power) and the blue one (device's 12V power). The communication between the Arduino and the Device can't ...


3

How a PID controller works depends on the particular implementation. There is a algorithm/library for PID on the Arduino: http://playground.arduino.cc/Code/PIDLibrary and an excellent explanation of the all of functions within it at http://brettbeauregard.com/blog/2011/04/improving-the-beginners-pid-introduction/ Over on stackoverflow and electronics, ...


3

I, also, didn't get the idea behind PID from just reading Wikipedia. After some videos/tutorials, I believe the best way to explain it is: What is PID PID is an algorithm. It involves three factors which can be adjusted to tune a signal. It is often used in servo's (and things like thermostates, basic signal controllers) Imagine this The servo will be ...


3

1) it is probably something like A1, A2, Common, B1, B2. You could confirm this with an ohmmeter. Common to any of the others would be a certain resistance X, while between any of the others (A1-A2, B1-B2, A1-B1, A1-B2, B1 A2) would be 2X. 2) You can't. It is a unipolar stepper. The EasyDriver faq number 5.1 at http://www.schmalzhaus.com/EasyDriver/ ...


3

What I do in situations like that is get some of those breadboard hookup wires, like you have in your second photo, cut them in the middle (giving yourself two wires, each with a bare end, and a end with a plug on them). Strip the bare end, and then solder it to the servo motor wires. Before commencing soldering, slip some heat-shrink tubing onto the wire. ...


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