jippie

Eindhoven, Netherlands

wirespeed.xs4all.nl/mediawiki

Age: 45

Do you love your Pets as much as I do? Check the Q&A proposal!

I'm into:

  • Linux;
  • Networking;
  • IT Security;
  • Perl;
  • System integration;
  • Arduino;
  • ATtiny & ATmega Microcontrollers;
  • Analog electronics;
14h
comment Arduino water solar heater pump control
@user28324 I believe you are right about the 40 mA, but total package current is like 200 mA and the GPIO pin output voltage will drop to maybe 2.5 or 3 volts at best, again those details are all in the datasheet. Every relay that respects itself has basic ratings printed on it. Those are maximum ratings and it is bad design practice to use a device close to those ratings. Like the ATmega, a relay has a datasheet too.
1d
comment Arduino water solar heater pump control
If the relay works with less than 20mA and a substantially lower voltage than 5V (check the datasheet for the microcontroller!) then it would work but still requires a diode. @user28324
1d
comment Are there any embedded Intel CPUs that can be soldered?
Why would you want to? Usually understanding the problem is half the answer.
1d
comment Arduino water solar heater pump control
freewheel, flyback
1d
comment Sepic converter
and the standard formulas, test circumstances, timing specifics, ...
1d
comment Misleading specification on an EEPROM chip?
The write protected memory contains a factory programmed abd globally unique address. "PRE-PROGRAMMED EUI-48™ OR EUI-64™ NODE ADDRESS. The 24AA02XEXX is programmed at the factory with a globally unique node address stored in the upper half of the array and permanently write-protected. The remaining 1,024 bits are available for application use."
2d
comment Electrical Machines based on Electric Fields
It's been ages for me since I've looked into things like this, but my first hunch would be to investigate the formula's around \$\varepsilon _0\approx 9 \cdot 10 ^{ -12 }\ \text{F/m}\$ and \$\mu _0 \approx 1 \cdot 10 ^{-6}\ \text{H/m}\$. Notice the difference in -12 and -6.
2d
comment Led Strip Heating Up
Stop tormenting your Arduino and start using current limiting resistors and/or MOSFET's.
2d
comment Why does output voltage increase when pwm input frequency to output enable increase?
You could probably interpret it as "kind of open", but you'll have to carefully look at what circuitry is attached to the output. It might be possible to fix or at least improve behavior. Add a circuit diagram to your question. Something as simple as a pull down resistor might fix it.
2d
answered Why does output voltage increase when pwm input frequency to output enable increase?
Jan
21
revised PWM Red LED on Stellaris Launchpad
edited body
Jan
21
comment Connecting a galvanometer directly to a microcontroller's PWM output
@NickAlexeev the diode in that circuit is used to clamp the voltage to a given maximum. If you over-power a galvanometer, the needle smashes itself into one of the corners which is suboptimal. As the PWM frequency is high enough, the needle moves really nice and steady. Only thing is not to set PWM over 6%.
Jan
21
comment Connecting a galvanometer directly to a microcontroller's PWM output
@NickAlexeev (1) Don't need the resistor for resolution, I have a 500 counts full scale on a 4 cm span ;o) (2) The impedance is about 1.8k, so maximum current would be in the order of 2mA at 100% PWM, but averages at 100 µA as that is the full scale.
Jan
21
comment Connecting a galvanometer directly to a microcontroller's PWM output
@EugeneSh. I want an analog read out of a digital value. I works just fine, I just want to know if it is a bad idea to do it without flyback diodes. The difference between need for a PCB with a couple headers and diodes, or two straight wires.
Jan
21
asked Connecting a galvanometer directly to a microcontroller's PWM output
Jan
21
answered PWM Red LED on Stellaris Launchpad
Jan
21
comment PWM Red LED on Stellaris Launchpad
Solved it. I was writing to GPTMTAMR where I should be writing to GPTMTAMR.
Jan
21
revised PWM Red LED on Stellaris Launchpad
added 353 characters in body
Jan
21
comment PWM Red LED on Stellaris Launchpad
Tracked the problem to an extra ROM_TimerConfigure(TIMER0_BASE, TIMER_CFG_SPLIT_PAIR | TIMER_CFG_B_PWM); at bullet 2, but unsure what the ROM call does different.
Jan
21
comment Advanced Microcontroller Lesson book?
Check out this little beast on a development board, priced very reasonable at $12.99(USD).
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