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  1. kellys_eye

    Security for Newer Vending Machines

    Here in the UK we find that a 'Yorkshire screwdriver' can open most things. Note - Yorkshire screwdriver = big f.o. hammer.
  2. kellys_eye

    Making Lead-Acid Style Batteries (With Alum / Epsom Salt)

    Great reply - and one I can definitely associate with. Good luck with your experiments!
  3. kellys_eye

    An1017A application note microchip

    Looks like you have to adjust the phase of the driving waveform to maintain maximum current flow in the windings as the speed increases (lag caused by inductive loading) - this is the offset value (in clockwise and counterclockwise directions).
  4. kellys_eye

    Don't connect vs no connect

    Under some circumstances the 'no connect' pin can be used to take a 'via' through a pcb whereas the 'do not connect' pin can't (since it has some internal, but unused, signal on it).
  5. kellys_eye

    Cant figure out data bus register problem

    Please post a schematic of the area of concern
  6. kellys_eye

    Vintage ADMIRAL 19A1 Chassis

    Yes, I can still hear the 15.625kHz of sets used in the UK (well, old sets...) and I'm pushing 60! It was only a few years ago (about 10 years) that I could hear bats! Mind you, I've never heard of anyone else that could do this. I'm weird.
  7. kellys_eye

    Vintage ADMIRAL 19A1 Chassis

    The HORIZONTAL (scan) frequency is 15kHz but the oscillator frequency used in the high voltage generation circuit isn't - they are separate parts of the circuit. But I don't think the frequency of the h.t is actually important - as long as you have 'any' oscillation you'll get the required...
  8. kellys_eye

    Van project fm and ir headache please help

    Why not just program your in-van radio tuner to a clear part of the spectrum and use that for audio via FM?
  9. kellys_eye

    Security for Newer Vending Machines

    They commonly use stepper motors (sometimes servo motors) which require a particular step sequence (correct order, correct voltage etc) to make it rotate in a given direction. Wrong sequence and it could rotate backwards or not at all. Sequence speed determines rotation speed. You can drive...
  10. kellys_eye

    Bench power supply advice

    The LM317 data sheet shows how to configure the device as both a voltage regulator and current limiter. The very low component count makes the solution very simple (and quick) to implement - a bridge rectifier, smoothing, two extra capacitors and two resistors - ta dah..... Robert's your...
  11. kellys_eye

    Security for Newer Vending Machines

    Short answer is a simple 'no' - you cannot make the motors work in the fashion you mention. Longer answer - the motors require a specific voltage, current and (most likely) a switching sequence that cannot be created by 'forced induction'.
  12. kellys_eye

    Bench power supply advice

    Here's an idea..... build a small box containing a couple of LM317's - one to regulate voltage and one to limit current. Fit one of those cheap dual V/I digital displays and fit a power socket on the rear - an INPUT power socket. In this way you can plug in any old wall wart, laptop PSU or...
  13. kellys_eye

    Bench power supply advice

    That's pretty compact for what it is already. I doubt any space you save from getting a smaller one would make much difference to your working space. If I had the 'spare' cash to purchase a smaller PSU I'd use it to purchase another (vital?) piece of test equipment and/or put it towards the...
  14. kellys_eye

    Making Lead-Acid Style Batteries (With Alum / Epsom Salt)

    I admire those that wish to experiment with battery construction but the subject is very, very well covered, especially recently with the increase in EV's and battery technology is improving all the time. As a DIYer it is unlikely that you will ever achieve a performance to match, let alone...
  15. kellys_eye

    One button to turn on esp8266 and as input.

    You need a current limiting resistor in the LED circuit. Not sure what you really want from that drawing....? What do you mean by 'turning the ESP on?' Is it in some power saving mode to start with? It's more common to have switches pull the inputs 'down' rather than 'up' - can you show a...
  16. kellys_eye

    RS232 to RJ45

    RJ45 sockets on the wall???? Running where? Surely they would be put in as part of a distributed network system and terminated at a 'switch'?? You can get protocol converters that will change RS232 to 'something else' and give an increased range but if this is simply a case of using a...
  17. kellys_eye

    Making a battery to charge my laptop on the road

    One last thing - if you want a reliable and long lasting power pack then you need to use the decent 18650's that are available - usually of the Panasonic brand https://www.amazon.co.uk/Panasonic-Battery-NCR18650B-3400mAh-401023-grey/dp/B00AIOH9VG at around $30 a PAIR....... you get my drift...
  18. kellys_eye

    Making a battery to charge my laptop on the road

    Crossed posts. Why not simply get a second battery for your laptop and carry a charged one around with you? This contains (1) the batteries (2) the protection (3) the regulation (potentially) and (4) comes with its own case. What it DOESN'T come with is a fire extinguisher because none is...
  19. kellys_eye

    Making a battery to charge my laptop on the road

    You have to REGULATE the charging current/voltage as well as provide various forms of protection (over/under voltage, over-current, thermal protection etc) - you can't just connect your power pack to a set of batteries as per the schema you post. Fire will ensue! There is also the problem of...
  20. kellys_eye

    RS232 to RJ45

    Why a cable change? What do you hope to achieve by this? RS232 is good for 50 feet or so, potentially further with a reduced capacitance cable (the CAT5 stuff) but 50ft is still an awful long distance! Either way, the article states: but providing the sending end pinout (however you care to...
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