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  1. Fish4Fun

    Drone flasher

    Hey Jack, Welcome to the Forum! As I mentioned, my vote is for a uC....cheap, quick and easy with an upgrade path for design changes....But, you are old and set in your ways, so let's answer AK's questions and see where this goes... @AK, Jack is a buddy of mine from the CNC forums...I...
  2. Fish4Fun

    Hovering Drone....W/Kg Calculation.....

    Hey Martin.....Actually I don't even have a quad, lol, I was just using the specifications from a DJi-550 to attempt to get a "real number" for Joules/Kg requisite for hovering....that part went exceptionally well....then I went and calculated the Relativistic answer.....it turns out if I could...
  3. Fish4Fun

    Hovering Drone....W/Kg Calculation.....

    Thanks For All The Responses! I at least feel a little better about having failed to find a "simple formula" .... I guess intuitively I "knew" the answer was in F = 1/2 mV^2.....I just couldn't think of a good way to work it out....If one thinks of a drone in water rather than air it is easy to...
  4. Fish4Fun

    Hovering Drone....W/Kg Calculation.....

    While not strictly electronics, the physics of a "hovering quad-copter" is a modern manifestation of a problem that has plagued me since high school physics.....the definition of work is Force x Distance and since "hovering" by definition is not moving.....there is a tad of a SNAFU calculating...
  5. Fish4Fun

    Replacing a 9Vdc relay with a transistor switch

    Hey Tim! Sure, anything that can be done with a relay can be done with semiconductors.....but sometimes it requires a great deal of effort to "make the switch" (all puns intended ;-) ) First thing to know is the voltages and currents being switched.....one would think the "sensor" might be...
  6. Fish4Fun

    Resistances of different lamps

    E = iR P = iE Therfore: P = E^2/R or P = R * i^2 So..... a 120W Bulb Nominally Rated for 12Vdc ==>> 120W/12Vdc = 10A ==>> 12V = 10A * R ==> R = 1.2ohms A 12W Bulb Nominally Rated for 12Vdc ==>> 12W / 12Vdcc = 1A ==>> 12V = 1A * R ==> R = 12ohms These are laws, not suggestions :-)...
  7. Fish4Fun

    How can I build a sine wave generator with variable phase?

    Openplanet, As I mentioned I think the easiest approach is to use a PC, there is no stand-alone piece of bench equipment even close in comparison wrt versatility, processing power and ease-of-use; however, if you are determined to try a wave form generator, then I would urge you to search e-bay...
  8. Fish4Fun

    How can I build a sine wave generator with variable phase?

    Openplanet, A good first-order attempt would, at the very least, involve a pair of microphones to "capture" the sound that you are going to attempt to actively cancel.....A "cheap and easy" place to get started would be with a PC...any PC built in the last decade has everything you...
  9. Fish4Fun

    How can I build a sine wave generator with variable phase?

    Hrmmmmm....I think we need to clarify the OP's problem.....My take on it is that the sub-station is creating sound waves that are bothering the OP.....several of the responses address problems associated with improper grounding of an audio amplifier.....I am not 100% sure my take is correct, but...
  10. Fish4Fun

    How can I build a sine wave generator with variable phase?

    Hey Openplanet, Welcome to the Forum! I understand what you are asking, but I am going to begin by correcting your syntax and a few other minor details.... Second, unless your local power sub-station is some specialized facility the "hum" you are referring to is likely 50hz or 60hz. What...
  11. Fish4Fun

    misc idea: small (3-phase BLDC) motors with built-in drivers.

    Hey Minder! I have to say that my experience with BLDC motors (not servos) contradicts this: with maximum torque at zero rpm for both ....in my experience with the hobby type BLDC motors there is virtually no torque in the lower RPM range, though I think in theory you may be correct....this...
  12. Fish4Fun

    misc idea: small (3-phase BLDC) motors with built-in drivers.

    Hey BGB! Hrmmm, I think we are still on different pages.... IF your goal is to drive NEMA17 motors inexpensively then DIY drivers are NOT the right way to go...have a look-see @ these...
  13. Fish4Fun

    Sensorless BLDC motor driven synchronously.....hrmmm...

    I have changed the code a bit to include acceleration into the synchronous drive firmware....this vastly improves starting reliability and "top speed"....The smallest motor now ramps up to over 600Hz, but I haven't connected an RPM sensor to it so I don't yet know what 600Hz translates to in...
  14. Fish4Fun

    misc idea: small (3-phase BLDC) motors with built-in drivers.

    Hey BGB! I thought I would let you and Minder hash out servos for a bit.....he certainly has worked with them a lot more than I have.... (all I know is a bit of theory.....and that I want to play with them, LOL) but at the end of the day if one wants to use a BLDC for precision movement one...
  15. Fish4Fun

    misc idea: small (3-phase BLDC) motors with built-in drivers.

    Hey BGB! ....Sleep + Caffeine have vastly improved my mental faculties....Let's see if I can get on your page :-) I concede I was thinking of "toy" robotics, not 10kg+ "monsters", but perhaps I am just looking at the wrong side of the page rather than the wrong chapter (to extend the...
  16. Fish4Fun

    misc idea: small (3-phase BLDC) motors with built-in drivers.

    BGB, First, I must confess i have not read your entire post....I read slowly, it is late and I am beat....so just ignore me if I am too far off-mark..... First....50W or 100W is not really "small".....assuming a 12Vdc nominal supply, you are talking about 5A to 10A....that is a lot of power...
  17. Fish4Fun

    GRBL + Arduino + CNC Plotter need help!

    Hey Giorgos! Have you read this: https://github.com/grbl/grbl/wiki ? After being generally fascinated with CNC machines since the 1980's, in the last decade I have actually built several CNC machines, and am currently building a 3D printer.....In my opinion the most difficult part of CNC has...
  18. Fish4Fun

    Sensorless BLDC motor driven synchronously.....hrmmm...

    Soooooo....it is nearly four months since my last post in this thread....not for lack of working on the project, but for a complete lack of progress.....I built several prototype triple-half-H-bridge circuits using the IR2110 Mosfet Drivers with dismal success until I finally had an epiphany...
  19. Fish4Fun

    PWM solenoid use

    Hey Randy! No worries.....there is absolutely NOTHING wrong with an analog circuit using a 555, Inverters, comparators, flip-flops or even discrete components....literally hundreds of ways to go, but .....if you plan on adding an Arduino board later on for other functions, then I think you...
  20. Fish4Fun

    PWM solenoid use

    On an Arduino.....Connect something like this to one of the ADC inputs.... ..... Obviously Set up//Enable the ADC in 10-Bit Free-Running Mode and a 16 bit timer with OCCRxA and OCCRxB IRQs Enabled.....Divider = 1 Assuming: .....Clock = 16Mhz ==> 292.5Hz = 57400 MCU Clocks .....5% = 171uS...
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