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  1. Old Steve

    Which transistors do I use?

    switch joysticks? http://www.alibaba.com/product-detail/4-way-joystick-switch_1032666951.html?spm=a2700.7724857.35.1.0dFksc&s=p All of the ones I've seen so far have SPDT or DPDT contacts though. You want one with SPST contacts on four sides. Edit: Actually, theyre not double-throw, just NO...
  2. Old Steve

    Please identify this component

    Yeah, I thought I'd better mention that, so Zapper doesn't think that simply replacing the buzzer will necessarily fix the unit. Looks like the buzzer has had a pretty decent blast of DC, maybe. (Or worse - AC mains or lightning strike?.) Edit: I have no idea whether it's a battery or...
  3. Old Steve

    Please identify this component

    Quite possibly. I considered that, but it's unusual that there's a space between V and 1.3 I don't think the meaning of the number is too important in terms of using it. I'll bet that any near-identical buzzer would work fine. It's very unusual to see a buzzer burn up like that. Makes me...
  4. Old Steve

    Which transistors do I use?

    Already, I see a couple of problems. 1. Are you sure that the original switches actually switch to ground? It's more common to see switches like those connected in a matrix for a micro to scan, in which case you'd need some sort of 'floating' switches, perhaps CD4016 or CD4066 analogue switch...
  5. Old Steve

    I need help locating something to measure current on a circuit and relay that via bluetooth.

    Doing it in the size that you want is a big ask. Are you capable of working at that scale, to build it? For the current monitoring, a microcontroller and an operational amplifier would be needed. The basic current measurement side is easy enough - you put an accurate resistor in series with the...
  6. Old Steve

    Which transistors do I use?

    Maybe I'm just slow, but I can't picture exactly what you mean. Can you draw up a schematic diagram and scan it, rather than trying to explain in words? I guess you're talking about connecting the NPN / PNP pairs as push-pull drivers, but still can't picture your connections.
  7. Old Steve

    Please identify this component

    Pretty slim. :D I guess it's possible, but I reckon it's just a bit of the part number. I doubt if they have a fixed voltage like that - they're sort of like a little speaker, driven by an AC waveform. (I think.)
  8. Old Steve

    Help in converting a wireless doorbell into a remote gate switch

    Excellent, I'm glad you saw my warning. I'd hate to recommend something that might cause damage. The top circuit is completely safe. Let me know how you go.
  9. Old Steve

    Help in converting a wireless doorbell into a remote gate switch

    I wasn't thinking clearly about Colin's circuit. Don't try it as I presented it!!! I don't know what I was thinking. It definitely needs a transistor. :oops: (It needs to connect between "Single Button" and "COM", not put a voltage between them.) Use the top diagram, not the bottom one. Edit...
  10. Old Steve

    Help in converting a wireless doorbell into a remote gate switch

    Right, "DT" it is. I guessed right. That's a 1K resistor. Your continuity tester probably won't register that as 'continuous'. If you measure between pin 11 and "DT", on a suitable resistance range, (2K?), you should measure 1K resistance. Just thinking about it, you might get away with Colin's...
  11. Old Steve

    Help in converting a wireless doorbell into a remote gate switch

    Just in case you don't know which is which, I've marked the PT4303's pin 11 here:-
  12. Old Steve

    Help in converting a wireless doorbell into a remote gate switch

    I think it will be a fairly simple matter to connect a transistor between the "Single Button" and "COM" contacts on the gate opener to trigger it. I can't find any data on the middle chip, the NT200M. I would have trouble soldering to that pin too, (bad eyesight), so we'll forget that option...
  13. Old Steve

    Please identify this component

    This is the best supplier I could find. $8.63 w/ free delivery to Oz:- http://www.aliexpress.com/item/100-Original-Loud-Speaker-Buzzer-For-N78-N82-5310-5220-N79-N85-N86-C5-00-Cellphone/32266917432.html
  14. Old Steve

    Please identify this component

    I just found a Nokia N78 to N97 buzzer that looks very similar, here:- http://www.lelong.com.my/enjoys-2x-ori-buzzer-ringtone-speaker-nokia-n78-n79-n82-n85-n97-enjoys-K757222-2007-01-Sale-I.htm Correction - it looks identical. :D The problem might be getting them to post it outside Malaysia...
  15. Old Steve

    Fm transmitter help

    Simon, do these results help at all:- https://www.google.com/search?q=f8v3080+hack&ie=utf-8&oe=utf-8
  16. Old Steve

    Drill bits for homemade PCBs?

    Yeah Dave, they're not bad. ex-Jaycar or Altronics. Mine would be 20 years old now. Something's rattling inside it, but it still works great.
  17. Old Steve

    Need help on servo motor output gear sizing

    They appear to range between about 15 and 25 splines. I found a lot of queries about exact numbers and angles of various types, and even did an in-depth search for more info on the (infamous) TowerPro MG996R and it's predeccessor, the MG995R, but found nothing definitive relating to this servo...
  18. Old Steve

    Drill bits for homemade PCBs?

    Martin, I was only correcting you in the same way you corrected hevans. Don't take it too hard. I didn't mean to get personal, but I guess it sounded like it. It was because when hevans said, "HSS bits will dull after only a few holes are drilled.", you said " I beg to differ with you." You...
  19. Old Steve

    Drill bits for homemade PCBs?

    That's true. Martin, but when drilling 1.6mm fibreglass PCB material with an 0.8mm sharp drill bit, even when you let the drill do the work, it goes through very fast. And the reason HSS bits dull so quickly when drilling PCBs is because of the glass. My drill is not too fast, well below...
  20. Old Steve

    Drill bits for homemade PCBs?

    I have one the same as your's Bob, but I found that using a drill press was more of a pain than it was worth, and much slower than drilling by hand with a small, lightweight drill, especially when there are hundreds of holes to drill in a variety of sizes. I keep my Dremel strictly for my...
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