Search results

Search Forums New Posts
  1. hevans1944

    Component acquisition for hobbyists?

    Cogito ergo sum. That's about all you say about it unless you dive into the rabbit hole of solipsism. Just My Stupid Opinion (JMSO) of course.:cool:
  2. hevans1944

    Component acquisition for hobbyists?

    It's been a fun ride these past 80+ years. I guess we humans will all eventually find out just how "real" it was. My current thoughts are: the Universe IS God. God is reality. Not sure just exactly what God is, but the usual superlatives apply. Pretty sure that, contrary to Albert, and based on...
  3. hevans1944

    First resonate a short antenna, then impedance match it ?

    Wasn't aware of this, but I did help a friend install unlicensed, low-power, wireless data links in office towers in downtown Dayton OH USA. The optical approach has the advantage of also not requiring a license. I also know a ham, Rex VK7MO, in Australia who is doing optical line-of-sight and...
  4. hevans1944

    Component acquisition for hobbyists?

    Actually, if you followed Stan Lee of Marvel fame, you would have realized the Universe is actually a Multiverse with an infinite number of dimensions. Good luck with that.
  5. hevans1944

    First resonate a short antenna, then impedance match it ?

    I joined Physics Forum (at your suggestion) because I need some "fact checking" on my optical designs for the transmitter and the receiver that I will use to demonstrate a "proof of concept" for amateur radio optical EME communications. So far, all I have received is "can't be done" responses...
  6. hevans1944

    First resonate a short antenna, then impedance match it ?

    Thanks for the invite to the Physics Forum. I joined, but immediately realized I had stepped into something waaay above my level of incompetence. Thanks anyway. ;)
  7. hevans1944

    First resonate a short antenna, then impedance match it ?

    Thank you @Delta Prime I have been busy elsewhere, mainly on X (formerly Twitter) conversing with Grok 3 [beta] on my optical-EME proof-of-concept demonstration. Starting to get a little traction on this, but if you want to see what I've been up to please visit (and ask to join: I will approve...
  8. hevans1944

    First resonate a short antenna, then impedance match it ?

    Aw, come on guys... simple answer is to add an impedance in series with the feedline that will cause the "antenna" to resonate. Then insert an antenna tuner between this kluge and your rig. Depending on the impedance you get after resonating the antenna, you may have to build or buy the antenna...
  9. hevans1944

    Component acquisition for hobbyists?

    I've been buying stuff from Amazon. Most of it is imported from Asia. Earlier in life, I would raid the dumpsters behind radio and television repair shops. I don't know if any of those "mom & pop" shops even exist now.
  10. hevans1944

    Stepper Motors & Drivers

    You are correct: there are many motors available with a NEMA 17 size frame. You need to determine which motor you need by measuring or calculating the amount of torque required to raise or lower the automatic door on your chicken coop. The amount of torque required will depend on the gearing...
  11. hevans1944

    Can somebody design me a circuit plan of this gadget (dodos)?

    For this type of "project" I almost always recommend "shake and bake". Place all the parts in a sturdy brown paper bag and shake the bag until parts are well mixed. Remove parts from bag and bake them in a medium oven at 200F until thoroughly warmed or browned, whichever comes first. Carefully...
  12. hevans1944

    Benefit from posting projects

    Wow! Whatta concept! Build it and they will pay you for it! Those of us who actually build stuff and describe what we have done here on Maker Pro, and perhaps in other places like QEX or QST (for hams), do it for our personal satisfaction and the hope that someone else will learn and be able to...
  13. hevans1944

    What more i can do?

    What a waste of time...
  14. hevans1944

    Schematic question ...

    If the secondary of your step-down power transformer were center-tapped, you could (1) remove the "ground" where D2 and D3 are connected, (2) connect the center-tap of the transformer secondary to "ground", and (3) get a negative output voltage where D2 and D3 are connected together, and (4) get...
  15. hevans1944

    Sharp 173 Photointerrupter

    This is just something you have to learn and know about: open-collector vs totem-pole digital outputs. The advantage of open-collector outputs is two or more outputs can be paralleled so that the output will be high if ALL the outputs are high, or conversely, the output will be low if ANY of the...
  16. hevans1944

    help peltier module

    Another drive-by poster who hasn't been seen since the original post on April 20, 2024. Also didn't really state what he (or she) wanted to DO. Why is polarity reversal of the Peltier device necessary? What is a water bottle dispenser? Does it dispense filled water bottles from a refrigerated...
  17. hevans1944

    28 Pin eeprom chip switch

    There is also an active-low OE = Output Enable pin that you must use if paralleling the outputs (recommended). _
  18. hevans1944

    pls help need to pass for my finals

    Well, here it is May and we still haven't heard any more from @mothman. In most places this is graduation season, so unless she somehow pulls a miracle from somewhere and passes her "final" it looks like this thread is done.
  19. hevans1944

    pls help need to pass for my finals

    We can help you if you do some work yourself. Show us what you do know and perhaps we can move you a little further along. This forum is not a one-stop shop for answers.
  20. hevans1944

    Best way to put off Fire from a Mobile Robot

    This is an ideal application for an AI-equipped robot. Make sure it has access to a fire hose and can manipulate the hose, nozzle, and water valve. Carrying a fire extinguisher around is not a practical solution. Try to get some practical experience from your local fire department on how to...
Top