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  1. EdwardM

    Timed dimmer (ie "Dawn simulator")

    Hi Dan doesn't sound too difficult, essentially it's just an alarm clock (4, 7 segment LED displays or LCD display plus some means of setting time and an alarm time).  Thereafter it's just a dimmer circuit, fired from fully off to fully on for a programmable time (another 2 switches). I'm...
  2. EdwardM

    circuit design

    Hi don't know if it will help but I'd consider using 3 of the parallel port lines to clock 3, 4-bit serial/parallel converters, each of which would be attached to a motor driver chip.  This will leave you a minimum of 5 parallel port lines available for your obstacle circuit (which could also...
  3. EdwardM

    Magnectic Sensor

    Hi u from what I understand, a magnetic sensor actually senses current, therefore if your closed loop circuit is driven by a voltage then it should be possible to detect that current using a combination of X, Y and Z coils to determine an exact position,  it depends also on how far away you...
  4. EdwardM

    LM353N

    Hi Imcondor welcome. As far as I remember the LM353 has been superseded by the lower power LF353, which is pin for pin compatible. Best of Luck Ed
  5. EdwardM

    Voltage level shifting

    Hi Staigen don't think so... I shifted the input gradually from 2.5v to 5v and got a gradual change of output from 0v to 5v which was the original requirement, this led me to believe that my original equation might be correct. Do let us know why you think that it's not linear. As you rightly...
  6. EdwardM

    Voltage level shifting

    Hi wk I now realize I was being a bit lazy about the circuit I described, I used an online opamp calculator to provide the starting values but they aren't quite correct. What I have done is obtained some AD8601 rail-rail single supply opamps and did a quick build using a 500K pot as the...
  7. EdwardM

    Voltage level shifting

    Hi Chaps R1 and R2 provide an offset voltage of about +2.5v (your minimum input), this means you need something more positive than that at the non-inverting input to make the output voltage rise above 0v. The value of all the resistors is almost immaterial provided that they maintain the same...
  8. EdwardM

    Problem Connecting to Site

    Hi Staigen I know what you mean, this site is much more personal than any of the others... Seems to be often on monday evenings UK time that I can't reach E-lab, maybe Mixos doesn't get out of jail until tuesdays?  ;D Ed
  9. EdwardM

    Multimeter Accuracy

    Hi anybody here, + or -  0.5% usually means that range of inaccuracy of full scale, there is also a residual potential error of + or - 1 digit. Is that any clearer? Ed
  10. EdwardM

    Voltage level shifting

    Hi wk with this sort of problem you have to start with the transfer function. In this case you are transferring an input of between 2.5 and 5v into an output of 0 to 5v and it should be linear, ie Vout = m*Vin+C. (The equation for a straight line). So m will equal the slope of the line...
  11. EdwardM

    caps

    Hi mettula Test for open circuit (which a capacitor should be) using high Ohms range, there may be an initial 'kick' of the meter display but it should become infinity. Test for short circuit, anything lower than infinity Ohms indicates leakage and the worst case being a short circuit (0...
  12. EdwardM

    Stepper motor controll

    Hi Gogo you could do worse than start where I did, after reading lots of contradictory material I bought a book called Easy Step'n, it's not high tech but down to earth practical advice on the care and feeding of stepper motors and how to get started with them and I highly recommend it. Best...
  13. EdwardM

    MSPS, kSPS ADC help

    Hi Adam, the short answer is a qualified yes.  1000kSPS = 1MSPS = 1 million samples per second thus 1 sample per microsecond.  Have a look at some ADC datasheets (Maxim, Analog Devices and others) to get some more detail. Best of Luck Ed
  14. EdwardM

    Need help with LCD displays....

    One of the best resources on the net for the HD44780 is http://ouwehand.net/~peter/lcd/lcd.shtml Best of Luck Ed
  15. EdwardM

    DVM??

    Hi All you could start your websearch at Analog Devices http://www.analog.com/en/cat/0,2878,760,00.html Best of Luck Ed
  16. EdwardM

    Making Life Easier

    Hi gogo I believe so, I think it is to prevent moisture interfering with components and the PC board and altering their electrical characteristics. Ed
  17. EdwardM

    Making Life Easier

    Thanks MP the conformal coating is a good idea and should enable the transition from prototype to 'production'.  The reason for posting this idea was mainly to pass on the results of a lot of frustration when designs didn't work, whether mine or someone elses'.  Many is the hour I've spent...
  18. EdwardM

    Making Life Easier

    Hi For some years now I've used a simple way of protoyping on 0.1in perforated boards which usually guarantees first time working.  I simply make an outline of each IC and pin name used as well as power supply terminals in a drawing program and then print them on paper.  Each outline is then...
  19. EdwardM

    +- power supplies

    Hi Ritmo2k I've tried to answer what I think is your question with a diagram... +5v means a positive supply relative to some common terminal and likewise -5v means a negative supply relative to some common terminal. Hope that helps Ed
  20. EdwardM

    Jammers

    Hi shiks Whilst I have no 'hands-on' experience of jammers, from what I've read, this is a big subject... If you are talking of radio reception jamming, this means making the reception of radio signals unintelligible or impossible in a particular region.  At least two and many other ways to do...
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