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  1. hevans1944

    Is this switch safe? Dual 26650

    My wife and I are supposed to quit smoking (again) this weekend. I considered trying e-cigs, but those just facilitate a nicotine addiction without ashes. I too have "an addictive personality" and cigarettes are the hardest addiction to break. I quit drinking in 1989 after twenty-something...
  2. hevans1944

    AC power generation and transformers

    Not too deep, maybe ten feet or so, and bonded to buried-in-concrete rebar grid. Good question, but I don't have a definitive answer. Some folks believe it is unsafe to live under or near high-voltage power lines, even if no immediate physical effects are apparent. It is probably safe to walk...
  3. hevans1944

    Is this switch safe? Dual 26650

    And what is "a mechanical box mod ecig" pray tell?
  4. hevans1944

    Generic RasPi talk

    The lack of deterministic behavior is just one of the things you give up when programs are loaded by a multi-tasking OS like Linux or Windows. The OS also has to manage the I/O to prevent conflicts among other programs executing in other threads. A real-time OS is a solution to the problem. In...
  5. hevans1944

    Controlling High Currents with Microcontroller

    Let me get back to you on that... after I do some homework. And... "a little coding"? Ain't no such thing. Coding always grows to fit the available execution space. :D
  6. hevans1944

    Controlling High Currents with Microcontroller

    Whoa! Program a Pi with C? And probably have to learn to use Linux too, eh? Does anyone remember Scotty, in Startrek IV: The Voyage Home, picking up a computer mouse and trying to give it voice commands? This movie was made in 1986! Surely a Raspberry Pi can understand my spoken instructions by...
  7. hevans1944

    Relationship between Frequency, Inductance and Resistance

    The author of the article stated, "The frequency of oscillation depends on the L/R time constant comprising the inductance under test and resistors RL and RR." I don't think using precision resistors would help much with accuracy. In a reply to the article, someone noted that the frequency...
  8. hevans1944

    Controlling High Currents with Microcontroller

    So, I guess we are all agreed that a PWM, driven from a boost switching supply to provide 15 volts across a 5 ohm load or 3 A output current, would provide the OP with a solution that could be implemented with a simple Arduino Mega controller... anybody here actually done this? I have both an...
  9. hevans1944

    Newb Needs Some Guidance

    I don't think it requires "four figures" to replace or re-program an inoperative key fob. See this website for example of an on-line service.
  10. hevans1944

    Controlling High Currents with Microcontroller

    I was thinking that with a fixed PRF the pulse-widths could never be zero-width, but you are correct that comparing a ramp against a setpoint to generate the pulses would do the job. Thanks for the tip. I should have remembered this.
  11. hevans1944

    3-Phase VFD Supply Pre-Filter

    Many years ago my boss decided to purchase a PCB manufacturing device for our electronics lab. I had been making PCBs the traditional way using photo-etching for quite some time, but my boss didn't much care for the messy chemistry. So, he bought this lathe-like contraption that rotated a thin...
  12. hevans1944

    Newb Needs Some Guidance

    If your automobile does in fact use the Texas Instruments encoder/decoder, there are way more than 999 codes. The key fob transmits a 40-bit code, which is something north of one trillion different codes. Since you have access to the fob and the car, there should be a way to pair the two of...
  13. hevans1944

    3-Phase VFD Supply Pre-Filter

    I am glad you have it working! On my to-do list is a CNC router table for woodworking. I just have to remember where I misplaced my round tuit to get it moving along. Are you using your spindle for metal working, or something else? Does it have a z-axis drive? I think probably not so much the...
  14. hevans1944

    Controlling High Currents with Microcontroller

    Don't forget that the OP, @user112358, wants a continuously variable range of current from zero to about 3 A to his 5 Ω load. How about a pulse width modulator connected to a boost supply that delivers 15 V? It could vary both the duty cycle and the pulse repetition rate, charging an output...
  15. hevans1944

    Help! Question about a pressure sensitive switch

    A CdS photoresistor is a good idea. Their resistance decrease from total darkness to even moderate illumination is huge, but probably not enough to serve as a switch for a string of LED lamps. You will probably need to add a transistor switch. If you can find a small, inexpensive, microswitch...
  16. hevans1944

    Capacitors in parallel effects on frequency

    I really do not like, and mostly avoid, circuits where potentiometers are used "backwards" and behave mostly like rheostats. I like to take the signal from the wiper of a potentiometer, not inject a signal into the wiper. But that's just the way I learned to use potentiometers. Your Mileage May...
  17. hevans1944

    Help! Question about a pressure sensitive switch

    I would buy some brass shim stock (it comes in a roll) so you can solder wires to it. You will need to cut with scissors two small brass strips and insulate them from each other with cardboard. Form a "J" hook in the bottom piece so that it will contact the top piece and complete the circuit...
  18. hevans1944

    How do energy plants safely measure power

    Folks, I think we are picking nits here. The OP @Agriias has a rudimentary understanding of electricity but neither he nor I work in the field of electrical power transmission. I cannot give specifics about which particular voltage transformers or current transformers are used, but these and...
  19. hevans1944

    suffleboard scoreboard help

    Save that transformer! It appears that it takes line power and steps it up to the voltage needed by the steppers. It may (probably does) have a lower voltage winding connected to a bridge rectifier to operate the 24 V DC coils of the relays. You could use those relays as electrically-controlled...
  20. hevans1944

    Newb Needs Some Guidance

    I provided a link to the Texas Instruments TRC1300 and TRC1315 MARCSTAR I E/D remote control encoder/decoders datasheet. Are you not using this particular IC in your key fob transmitter? TI realized that it is sometimes necessary to pair these devices in the field after they are paired by the...
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