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21
General Electronics / Re: Controlling High Voltage i...
Last post by Sylvek - Today at 10:07 pm
Hi
With this 400V it was my bad. This is max voltage as you say. Low voltage impulse is around 0.5-2.0V so I can easily check this parameter with arduino. So thyristor will be fine option?
22
General Electronics / Re: WCS1700 Noise problem
Last post by Wawa - Today at 10:04 pm
Hall sensors are always noisy, your only recourse is low-pass filtering to average the
readings over a longer time period, or use a better technology.

Note that that device has no accuracy specification at all in the datasheet!  Not very
encouraging.  Its sensitivity depends strongly on supply voltage too.
Datasheet mentions a 10-100n cap across the analogue input.
And yes, snoothing code could improve noise.
There could be another problem. We don't know what OP is measuring.

Looks like someone took a standard C-core, put a standard hall sensor in the gap, and encapsulted it in plastic.
I think one hall sensor is much the same as another.

The ratiometric code I posted compensates for that varying sensitivity.
Leo..
23
Generale / Re: informazioni su codice att...
Last post by SukkoPera - Today at 10:04 pm
Il codice lo scrivi tu, mica un'entità superiore... Ergo decidi TU cosa fare!
24
Quote
How to use an LCD without liquid crystal library.
Often ridiculous requirements like this are part of an assignment. Is it homework or course work?

If not why this silly restriction?
25
That is the usual way to use an nRF24 module. The I/O pins are 5v tolerant but it needs 3.3v on the power pin.
This only means one can send data to the nRF24. The ATmega328P datasheet states that Vih must be .7 VCC minimum. If running at 5 volts, this means logic high must be 3.5 volts or greater.
26
By following movement I am simply assuming you want the head to turn to where-ever there was most recently a movement of an object. I am assuming you don't want it to try to track people in the room via any kind of image recognition, this latter would need a camera connected to something like a raspberry pi to run image recognition software then send commands down to and arduino to control a servo. The former could perhaps be done by mounting a distance measuring range-finder sensor such as a HC-SR04 or a laser equivalent VL53L0X (both with ranges a bit over a metre) on some kind of rotating turret, this turret would rotate fairly fast (perhaps once a second or so) and would take a range reading every (for example) 5 degrees. It would probably be best to measure those 5 degree positions by having the rotating turret trip a microswitch and the arduino consult the rangefinder for a distance every time the switch was tripped, the alternative would be trying to have the arduino consult the sensor a known time apart, but the motor driving the turret might not have a reliable enough rotation speed for such a time triggered sensing method to consistently take readings in the same places. To avoid needing slip-rings for connection to the rangefinder you'd probably want the turret to swing to +170 degrees then -170, then back to +170 via 0. The arduino would know how many readings would be taken during each sweep and would detect whether the readings changed between subsequent sweeps of the turret. It would store the readings in an array of however many different angles it had readings at (68 positions for my 5 degree measurements, -170 to +170 sweep example), best to keep the readings as byte values rather than ints and definitely not as floats hence ensuring plenty of memeory space to store the 68 readings in. When the program on the arduino saw that a distance reading had changed by, say, more than 20% it would turn the doll's head (which would be on a separate turret to the rangefinder and would be controleld by a separate servo) to face the direction where there had been a change in reading. If there had been changes of more than 20% in more than 1 of the 68 readings then you would have to decide whether to turn the head to face the one which had changed by the greatest percentage or the one which had the closest range reading. Good luck.
27
Microcontrollers / Re: cannot compile for Adafrui...
Last post by westfw - Today at 09:53 pm
Quote
even uninstall and reinstall the Adafruit package didn't help, same error.
uninstall leaves a bunch of staging files around, I think, so it doesn't do as good a job at cleaning as you might expect.
Quote
as it seems, deleting the Adafruit folder in "portable\packages\"
That would have been my advice (assuming you have "portable."  Otherwise, you need to go digging in the Arduino15 directory...
28
You could always use the code in the datasheet:
Code: [Select]
/* The following code examples show how to initialize the SPI as a Master and how to perform a simple transmission. DDR_SPI in the examples must be replaced by the actual Data Direction Register controlling the SPI pins. DD_MOSI, DD_MISO and DD_SCK must be replaced by the actual data direction bits for these pins. E.g. if MOSI is placed on pin PB5, replace DD_MOSI with DDB5 and DDR_SPI with DDRB. */


void SPI_MasterInit(void)
{
  /* Set MOSI and SCK output, all others input */
  DDR_SPI = (1 << DD_MOSI) | (1 << DD_SCK);
  /* Enable SPI, Master, set clock rate fck/16 */
  SPCR = (1 << SPE) | (1 << MSTR) | (1 << SPR0);
}
void SPI_MasterTransmit(char cData)
{
  /* Start transmission */
  SPDR = cData;
  /* Wait for transmission complete */ 
  while (!(SPSR & (1 << SPIF)))
    ;

}
29
Quote
I have tried using an Opto-coupler to detect the individual voltages but the coupler cannot measure variations in the battery voltage drop.
It can if it uses the right sort of optical isolator and operational amplifier.
30
Deutsch / Re: LED leuchtet nicht dauerha...
Last post by gregorss - Today at 09:51 pm
Da bin ich mir nicht so sicher. Das 2. Foto vom Versuchsaufbau sah ja (fast) genauso schlimm aus.
Naja ... vielleicht ist das, was die dann in die Hose geht, worüber dann andere Witze reißen. Der Zusammenhang zwischen Naturgas und Genialität ist manchmal jedenfalls offensichtlich.

Gruß

Gregor
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