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  1. hevans1944

    Motor identification

    Wow! That's a pretty nice telescope, although the supporting hardware has had some mixed reviews. Meade seems not at all inclined to help the amateur with repairs or modifications. So, assuming the electronics is toast or beyond cost-effective (or affordable) repair, your only hope is to drive...
  2. hevans1944

    why is this comparator triggering on falling edge?

    That doesn't sound like very good engineering practice. If you don't have time to do it right, where do you find the time to do it over? Shotgun engineering may be okay for amateurs pursuing a hobby interest, but it isn't real engineering. If you just read the parts of the data sheet you...
  3. hevans1944

    why is this comparator triggering on falling edge?

    I really do like BSH components, but in today's world of disposable electronics, hardly anyone uses them except by accident.
  4. hevans1944

    need source of inexpensive solenoids

    Have you looked on this Google results page?
  5. hevans1944

    problem sourcing capacitors please help

    You could attach insulated hook-up wires to the capacitors, insulate where the wires attach to the capacitors, and solder the other ends to the circuit board. Then stuff the capacitors where ever you can find space for them. Keep the wires as short as possible, but a few inches should be okay...
  6. hevans1944

    Motor identification

    This could be a really fun project to "reverse engineer" the motor control circuits for your alt-az mount. Can you provide a model number for the Meade telescope? I am sure there are Meade blogs and forums where you can also get a lot more help. I have been fascinated with optics and telescopes...
  7. hevans1944

    Motor identification

    It looks like a permanent-magnet (PM) DC motor with either an optical encoder or a tachometer attached to the end. Is there a gear-reduction box between the motor shaft and the telescope mount? Is this an alt-az mount or an equatorlial mount? You should be able to detach the blue and orange...
  8. hevans1944

    Need the Datasheet or specifications of NIC0K1L( ultrasonic transmitter receiver module.)

    I have had several ultrasound scans of my neck carotid arteries. The person who did the scans said that flow velocity is measured by the Doppler shift it creates in the reflected ultrasound. How they get a 2D image is beyond my current state of knowledge, but imaging wouldn't be necessary to...
  9. hevans1944

    Advice for temp controlled fan

    Yeah, I was intimidated for years by the prospect and pre-conceived difficulty of working with SMD. But once I actually got involved about two years ago, it did not appear impossible. Just different tools and techniques. Fortunately, there are lots of YouTube videos for training purposes. Some...
  10. hevans1944

    Advice for temp controlled fan

    That sounds reasonable. Glad you are making progress! You could put both comparators on the same board with the two relays and run wiring to the temperature sensing outputs of the existing two boards. But if you want to build two boards, each with a comparator and a relay, you would have a...
  11. hevans1944

    Advice for temp controlled fan

    Right, as usual, Kid. I assumed he just wants to drive a relay or an SSR from the comparator output, and size either one appropriate to whatever auxiliary fan he decides will work, but it would be possible to drive a small 5 V computer fan directly, or with a small transistor buffer. This is a...
  12. hevans1944

    Advice for temp controlled fan

    You get hysteresis in a comparator by using positive feedback from its output to the non-inverting input. This is typically implemented with a voltage divider between a reference potential and common to establish a trip-point input level, the divider output being connected to the non-inverting...
  13. hevans1944

    relay sticking

    If you can get the relay on the controller board working properly, either by dressing the contacts with a very fine small file or spraying them with WD-40, then you can use those contacts or the voltage applied across the relay coil (as suggest in post #10 by @duke37) to energize the control...
  14. hevans1944

    Advice for temp controlled fan

    I like the LM311, but it is a bit of overkill for a simple temperature-sensing application, where the monitored value changes slowly and does not require a fast response at the trip-point levels. The ubiquitous LM741 or LMx58 series of dual op-amps will work just as well when configured as...
  15. hevans1944

    Microcontroller ClockCycle speed thing question

    It depends not only on the clock speed but also how many clock cycles are required to complete a given instruction. Refer to the datasheets of specific processors for this information.
  16. hevans1944

    Advice for temp controlled fan

    An analog comparator driving a relay to control the fan will work. You can use the output state of the comparator to set the trip points, implementing whatever hysteresis you desire. Unfortunately, the State of Florida (to which I have now retired) does not allow me to provide specific answers...
  17. hevans1944

    Headset specs

    See my comments in red within your quote above.
  18. hevans1944

    Simulate the software before flashing

    I don't trust software simulators much, because software that checks "good" in the simulator may fail in the final hardware install, usually because of real-time timing issues. These can be a real bitch-kitty to troubleshoot and correct. It is okay to use simulation to verify the correctness of...
  19. hevans1944

    Hello

    Welcome aboard Electronics Point, Beau! You are going to love EP threads on microcontrollers. There are also several Hams lurking here, including myself (AC8NS). What amateur radio bands do you work? Is your call sign KK4RCF?
  20. hevans1944

    Noob Soldering Problem - Which Wire To Use?

    Which is why I have a spool of tinned bare wire of various gauges and another box (somewhere) of insulation tubing sized to fit over the bare wire. My favorite "go-to" stock is a small spool of 22 AWG solid tinned wire and a spool of Teflon tubing that fits nicely over it. For any newbies...
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