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  1. kellys_eye

    Bit of quiz fun

    I used to enjoy doing the occasional Sudoku puzzle and was amused when a hexadecimal version of it started doing the rounds. Just for fun I reproduce here a typical puzzle that I invite other forum members to have a go at. The usual Sudoku rules apply however this one requires 0-9 and A-F in...
  2. kellys_eye

    Critter Zapper

    You want an 'electric fence energiser'. Making a 'permanent' high voltage supply is wasteful of energy especially if you want to power it from a battery so a 'pulsed' output saves considerably. Here's the schematic of a typical unit that was published in an electronics magazine. It can be...
  3. kellys_eye

    Issue in driving sensored BLDC motor

    Sounds to me like a typical case of drive signal 'overlap' - when your drive signals don't have sufficient 'separation' to prevent the top/bottom devices from switching on together. Transients on the supply line? It may be related to the junction capacitance of the FETs you're using too...
  4. kellys_eye

    vu meters diy

    There is more than one way to skin a cat (they say) so making your own 'mechanical' meter has a number of possible solutions. Might I ask why you want to 'make' one?
  5. kellys_eye

    vu meters diy

    Blimey - is Google down?? https://www.google.co.uk/search?q=moving+coil+meter&tbm=isch&tbo=u&source=univ&sa=X&ved=0ahUKEwiBvLyAia7VAhXJYVAKHcPEC2cQsAQIcQ&biw=1855&bih=1073 :D
  6. kellys_eye

    Replacing Large PCB Pin-Headers/Eurocard?

    Cutting the pins from the 90 degree connector then desoldering them individually seems the easier way. I'd use a dremel tool and slice the connector as close to the board as possible - you could use a hacksaw too if you were careful - and I mean careful!
  7. kellys_eye

    Ultrasonic Water Level Sensor design

    You will need matched transmit/receive sensors to detect range. Can you get the datasheet for the individual transducers?
  8. kellys_eye

    Salvaged components

    I refer to it as 're-purposing' or 'up-scaling' depending on how the parts are either acquired or used. Occasionally I will purchase old equipment (eBay etc) simply to dismantle the item for parts that I know are in demand and normally cost a lot of money. Around 10 years ago I purchased what...
  9. kellys_eye

    LED stripe resistor

    Those LED strips consume around 24W per 5m length - your use of a 50W power unit for powering TWO strips leaves no margin for error and may cause premature failure of the power pack. You should allow at least 25% margin for overload therefore a power supply rated at least 75W would be a better...
  10. kellys_eye

    LED stripe resistor

    The preferred method for dimming LEDs is to use a PWM controller. Your links don't work - they only take you to an eBay log-in page.....
  11. kellys_eye

    Woo-Woo Electrical R of a plant leaf vs. human thought

    Really? ...or - obviously because you don't want to accept the findings of a program that has never (in my experience) influenced the outcome of any 'bust' for any reason. Why would they choose this occasion to be deceptive? What on earth gave you the notion that they would deliberately...
  12. kellys_eye

    keypad interface with controller

    Most keypad matrix wiring is based on the standard column/row method where you sequentially poll the column whilst reading the row (or vice versa).
  13. kellys_eye

    keypad interface with controller

    RB0 and RB1 should supply a logic 1 to their respective resistor packs (2 lots of 5 resistors) and each bank of 5 switches should pull RB2 to RB6 respectively to ground. Your schematic drawing convention is particularly 'disturbing' and makes for incredibly difficult understanding.......
  14. kellys_eye

    Where to start

    Not heard of GCB but will give it a look over. If Basic is your 'thing' then for PIC programming I use PICBasicPro: http://www.picbasic.co.uk/forum/content.php?r=406-Features&s=162bc7dca33fefc63cc606dd99ea3a49 It is feature-rich, has a great forum where you can get advice and it supports 500...
  15. kellys_eye

    Power-One power supply mod

    If you purchase TWO power supply kits and they are built as 'isolated' outputs (i.e. no common ground) then you can chose which wiring method you like and either use them singly, in series (additive) or as a +/- source as you wish simply be wiring the output terminals accordingly. When...
  16. kellys_eye

    Water Proofing (light up) Fibre-Optic Vest and battery

    The LED fibres are none conductive and 'solid' (AFAIK) so won't allow water ingress. As Audioguru says, if it's low power and fresh water then the battery system will work for as long as you state you need it to however if the battery pack is of any issue then placing it in an IP67 rated box...
  17. kellys_eye

    Where to start

    To do the functions you want - especially accessing USB - you'll struggle doing it with assembly language. This is where high level languages come into their own and, for the Arduino (and others) there will inevitably be library routines that handle the complex parts of the programming to avoid...
  18. kellys_eye

    Replace catalytic element on Iroda MJ-950 heat gun?

    ...and if you want to purchase 5,000,000 of them they won't be 'expensive' either :p Thereby lies the rub. It will inevitably be cheaper to purchase a new tool than to find a replacement part that isn't normally available as a spare. That iron is quoted on Farnell at around £32 ($50??). If...
  19. kellys_eye

    Water Proofing (light up) Fibre-Optic Vest and battery

    Not sure how the light is emitted - if it's from a point-source LED then all you have to do is water-proof the area where the LEDs are fitted..... and thereby starts your problems. Waterproofing isn't easy and most certainly when you're starting from a point where the item in question isn't...
  20. kellys_eye

    Replace catalytic element on Iroda MJ-950 heat gun?

    The catalyser is a fine material coated in a chemical compound that flakes off over time and if you aren't getting a decent 'glow' then it usually means replacement of the catalyser - if you can get one. So long as it's still producing heat though..... Personally I use gas tools that...
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