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  1. hevans1944

    Board to monitor power to 3 lines and transmit via Bluetooth for a stateful type configuration

    There is also a LOT of free help available on the web in other forums devoted to Arduino and Bluetooth. Lots of software, or "sketches" as software is called in the Arduinoverse, to get you up and running fast. I bought a couple of Arduino Uno μPs last year and added Bluetooth carriers made by...
  2. hevans1944

    Cheap coffee maker

    Sorry, I didn't thoroughly research this for you. And I also didn't realize that after the empty water reservoir of the coffee maker cools down, then the switch will close again and continuously cycle between on and off as it tries to heat up water in a dry reservoir... not a good feature. Yes...
  3. hevans1944

    Board to monitor power to 3 lines and transmit via Bluetooth for a stateful type configuration

    You could implement this with a pair of Arduino microprocessors equipped with Bluetooth shields. Some programming required, but all components are off-the-shelf and readily acquired. The Bluetooth signal would be a frame of data encoded with three bits representing your three channels and the...
  4. hevans1944

    Component getting too hot and I dont know why

    Do the math. You are dropping 9 V (13.8 V - 4.8 V) across the 7805 at 0.242 A, so it must dissipate over 2 W. I don't see a heat-sink attached in your photograph. Bolt a good heat sink to that puppy and see what its temperature rise is. Learn how to obey the laws of thermodynamics. Wishful...
  5. hevans1944

    AC current sensing circuit/relay

    A Hall Effect current sensor driving an analog input of a PIC microprocessor makes a nice solution. Some assembly required, both hardware and software. Interested? Send a private message to @chopnhack, who has a thread here on how he did this to control a dust collector when AC current in...
  6. hevans1944

    Cheap coffee maker

    Maybe you are looking for the wrong part number. An uxcell KSD301, 250V, 10A, N.C. Temperature Controlled Switch that opens at 135C should work fine in a cheap coffee maker. It will trip open when the water reservoir boils dry and the temperature rises from 100C to 135C. Available here at...
  7. hevans1944

    Most inexpensive method for detecting if some current is flowing in 120VAC or 240VAC PCB Trace

    An inexpensive Hall Effect sensor is probably your better alternative to a low-resistance current-sensing resistor. You can also measure the voltage drop along a length of PCB trace (will be in the low millivolts to microvolts range, depending on geometry of trace and current through it) without...
  8. hevans1944

    Thyristor controlled flash gun

    Well, probably you won't be able to find replacement parts without a schematic diagram and/or a BOM (Bill of Materials, aka parts list). Before packing it off to the "great flash graveyard," consider purchasing a used replacement at a reasonable cost. You can then use the replacement for A-B...
  9. hevans1944

    XR2206 DIY signal generator kit.

    It's good that you set a spending limit for your electronics instrumentation. I have no idea what a "good" signal generator goes for today, but I needed several over the course of some sixty-plus years futzing with electronics. I broadly divide them into two categories: audio-frequency-like and...
  10. hevans1944

    XR2206 DIY signal generator kit.

    New will usually get you the latest state-of-the-art, which is important with digital oscilloscopes and most other electronics instrumentation available today. But no matter when you buy, realize that it will be obsolete by the time you receive it, replaced by a newer model that is less...
  11. hevans1944

    What is your troubleshooting sequence?

    I agree, "dumbing down" is a proper description, but given the "pool" of talent available to industry and the military, there is only so much you can expect a "technician" to accomplish. Swapping out possibly bad components for "known good" components goes back to the days of vacuum tube...
  12. hevans1944

    Significance of CPOL and CPHA in SPI communciation

    There are four setting combinations of CPOL and CPHA, so depending on your hardware and software SPI interface, you may have to choose one of the four for the master device. All the slave devices synchronize to the master, so it isn't necessary to set these two parameters for the slaves. More...
  13. hevans1944

    Heathkit ET 3400

    As I said: Good Find! Some of my fellow technicians in the 1970s bought KIM-1 6502-based processors to learn with. I had better financing and support from management, so I was able to purchase an Intel Microprocessor Development System to develop 8080 software. Later, after I graduated in 1978...
  14. hevans1944

    Heathkit ET 3400

    Good find! Now go build a nice shadow-box, with a glass cover to keep the dust out, and mount this ancient treasure on a wall in your living room or man cave. Go buy some modern microprocessors and learn how to program and use them. You will learn nothing useful playing around with this ancient...
  15. hevans1944

    Reading value from Solar Panel Cell, current peak concern

    The solar hot water heating system I saw in Tucson, AZ, back about 1979 or thereabouts, wasn't terribly sophisticated. It did use vacuum-insulated, transparent, coaxial glass tubing to contain the water surrounded by vacuum, factors that probably jacked it's cost up beyond profitability...
  16. hevans1944

    Reading value from Solar Panel Cell, current peak concern

    I don't suppose you have access to the roof of your apartment building... roofs are good places to mount solar collectors.
  17. hevans1944

    I need help with the Logic Analyzer in MPLAB 8.92 please

    Certainly glad you got that sorted! Do the logic analyzer wave forms act according to your conception of what they should do? Is the logic analyzer of any help in debugging or testing your program?
  18. hevans1944

    Reading value from Solar Panel Cell, current peak concern

    270 Ω and 330 Ω are both standard values for resistors. Color code for 270 Ω is red-violet-brown. Color code for 330 Ω is orange-orange-brown. Use your multimeter to measure the parallel combination of your seven resistors instead of just one of them. That will tell you whether you have any cold...
  19. hevans1944

    I need help with the Logic Analyzer in MPLAB 8.92 please

    Well, except the logic analyzer doesn't appear to work properly. I've never tried to use the logic analyzer, so am totally unfamiliar with its idiosyncrasies. Apparently there are many, mainly because it is OLD and Microchip hasn't put forth any effort to support it. If I even get involved...
  20. hevans1944

    I need help with the Logic Analyzer in MPLAB 8.92 please

    Is there some reason you haven't upgraded to MPLAB X IDE instead of using MPLAB 8.92? If you upgrade (it's free of course!) then you might want to read this Microchip forum post. Ummm,,, you did visit the Microchip forums before posting here of course... riiiight? Word on the street is the logic...
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