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  1. hevans1944

    Interfacing joystick

    I am not familiar with the Texas Instruments power op-amp product. In the past I have used a hybrid power op-amp, the PA-12, made by Apex Microtechnology for various low-frequency applications up to a few kilohertz driving inductive loads. I think the TI product is an improvement because it is...
  2. hevans1944

    Building a time delay relay circuit with 555 timer

    The U.S. Air Force is responsible for training me up on the AN/ASG-21 and MD-7 Defensive Fire Control Systems in 1963. I fell in love with it! Lots of servo mechanisms, Ku-band radar, electro-mechanical ballistic computer to solve the aiming problem for the M-61A1 Vulcan 20mm Gatling Gun...
  3. hevans1944

    Building a time delay relay circuit with 555 timer

    You are correct. The image processing software locates and identifies whatever you want to track. You are offered the opportunity to move a cursor in the image to select a different target if you don't like the target the machine picks for you. I had the opportunity to observe this target...
  4. hevans1944

    clever vibration motor driver?

    I am sure the circuit will work just fine with analog control of the motor via the LDO regulator instead of PWM with a MOSFET. But I wonder, where did you get that waveform? It looks like the underdamped response from an inductor that has had a step function (or a really narrow impulse function)...
  5. hevans1944

    Building a time delay relay circuit with 555 timer

    Yes. It has existed for quite some time under various names using various sensors. Some common names are thermal imaging and forward-looking infra-red (FLIR). The technology is based on detecting and measuring infrared radiation near 15 μm wavelength. This happens to correspond to the peak of...
  6. hevans1944

    clever vibration motor driver?

    I am new to using MOSFETs (except for those that are an integral part of CMOS digital logic), if you can believe that. I was always under the impression that they were hard to work with as discrete components, being overly sensitive to static discharges, over-current, over-voltage, yada yada...
  7. hevans1944

    Building a time delay relay circuit with 555 timer

    Make sure the PICs you purchase are in plastic dual-inline packages (PDIPs) so you can handle them. The first ones I bought are SO-23 and almost impossible to work with. You will also need the PICkit 3 Programmer to download programs to whichever PICs you use. I would get whatever clear plastic...
  8. hevans1944

    Building a time delay relay circuit with 555 timer

    I happen to have some PIC10F206 μP chips handy, so I could try to program one for you. Might be awhile though, because I have other things to do... like finish my now-going-on-twelve years bathroom remodeling project. If you are interested in learning how to program PICs you need to purchase a...
  9. hevans1944

    clever vibration motor driver?

    I think it is a clever idea. Quick and dirty and wastes a little power, but it should be good enough for "proof of concept" while you program the MCU. Make sure you adequately heat sink the TO-25 package and choose a low-drop-out (LDO) regulator. However, since you already have an MCU, why not...
  10. hevans1944

    Building a time delay relay circuit with 555 timer

    Hey! @irishluck What's with the 555 analog POS timer, when you can do the same thing at lower power with a 6-pin PIC10F206 and use either a phototransistor OR an LDR? This is the 21st Century and the Digital Age, folks. Get with the program! (pun intended) :D
  11. hevans1944

    worth learning electronics

    No, it is NOT true, although some manufacturers would like you to believe that. The biggest problem is identifying and purchasing replacement parts. Some of these are proprietary to the manufacturer, who can be pretty choosy about who is allowed to purchase them. Commonly available parts like...
  12. hevans1944

    Position of one device relative to another.

    Martin is probably using a pulse-doppler IR ranging and tracking system coupled to an optically-steered Q-switched laser to zap flies. Well, that's what I would use. Or a paddle with a lot of holes in it on the end of long stick. Depends on whether you prefer squoosh or smoke.
  13. hevans1944

    Position of one device relative to another.

    I would like to know how you would do this with "IR or something" instead of GPS. For GPS you need to know the space coordinates of both objects (two GPS receivers) and some way to communicate that information. After that, it's just a matter of solid trigonometry to calculate direction and...
  14. hevans1944

    3 way/4 way switch

    The lamp will also be on if you move the 3-way switch on the left side to connect the movable arm to the upper contact. Each of three switches has two positions, so all three together have a total of eight possible positions, four of which you have diagrammed above. For half of the eight...
  15. hevans1944

    Need help finding a replacement transistor?

    As long as the transistor is rated for a higher voltage than what you are applying to it (7.5 V in this case), you are good to go.
  16. hevans1944

    Need help finding a replacement transistor?

    And if that IS a 2SB826, the 2SD1062 next to it is the other half of an PNP/NPN complementary pair. Google 2SD1062 for a datasheet describing both parts.
  17. hevans1944

    My Introduction Thread

    Welcome aboard, Andrew. There is no admission fee to learning electronics. When you start building "projects" you will want some basic test equipment and hand tools, but there is no end to it. The more you learn and the more you play the more you spend. It is a hobby for many people here and for...
  18. hevans1944

    Need help identifying this part

    Well, it probably is a power resistor of some lowish value, perhaps to sense current in a circuit. The resistance element would be the black stuff between the interdigitated fingers. It looks like there are two interior terminals on either end, and another two terminals spaced outward from them...
  19. hevans1944

    Make electronics : experiment 8 problem

    @harley quinn I am sorry if it appears that I was a little short in my comments. I am not a big fan of the maker community or the so-called "instructables" that pop up here, usually with "why won't it work?" type questions. There is a lot of misinformation on the Internet and it is difficult for...
  20. hevans1944

    Need help identifying this part

    I think "what it is" would depend on the substrate material. It could be a light-dependent resistor, or a surface acoustical wave filter, or maybe even a thin-film or thick-film resistor. Whatever it is, it looks like it has seen better days. Was this salvaged from equipment, and if so, what...
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