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  1. Old Steve

    Electro magnet

    Way too weak. With 8, you'd only have 20kg of force to clamp the bar. And it would be near impossible to connect a group of 4 to each end. Better is to connect a single, long-travel, piston type solenoid to each end of the clamping bar from underneath, which is the way the 'Magna Bender'...
  2. Old Steve

    Hand Sanitiser Dispenser Circuit

    Your first idea isn't bad at all. Your second idea is blasphemy. :D No electronics! Bah humbug.
  3. Old Steve

    Battery discharging circuit not working

    Sorry I was so slow to pick up on the chip name and the fact that you'd also tried an NFET last night. It was very late and I was exhausted after a hard day writing two uC programs. Have you solved this yet?
  4. Old Steve

    Multi-input D flip-flop?

    If you only have the one flip-flop, with one output, why would you need to single out a specific input? And if you need to single out a specific input, one flip-flop isn't enough. As mentioned, your description is lacking. Draw a simple circuit with your supposed flip-flop, showing it's use, and...
  5. Old Steve

    Battery discharging circuit not working

    Right, now we're on the same page. You said the resistor is not being grounded, but it must be I guess. You've measured from the bottom of the resistor to ground? What you really meant, I suppose, is that the other end of the resistor isn't connecting to the battery through the Darlington pair?
  6. Old Steve

    Battery discharging circuit not working

    Well, if the dsPIC pin is going low high, but the bottom of the resistor isn't being grounded, there's only one thing in between. Hard to read, but looks like 74HC something. Is it a 74HC05 open-drain inverter, in which case I guess the dsPIC pin must go high to ground the resistor. The 74HC05...
  7. Old Steve

    Battery discharging circuit not working

    If the 10 ohm resistor isn't getting grounded at all, doesn't it have to be a problem related to the dsPIC? Are you sure the dsPIC output pin is going low?
  8. Old Steve

    Multi-input D flip-flop?

    That was a diode 'OR'. For reference, in case you ever need it, you can create a diode 3-input 'AND', too, by reversing the diodes and connecting the resistor to +V instead of GND:-
  9. Old Steve

    Multi-input D flip-flop?

    Why not connect your 3 inputs to the one 'D' input with diodes, like in my sketch:- (Standing on their ends, 3 x 1N4148s wouldn't take up much space.) For multiple clocks, they could be connected the same way - 3 more diodes.
  10. Old Steve

    Mind & Infra Red Controlled Robot Car

    Yeah, don't be concerned about C. It'll all fall into place. I can't give an opinion on the HC-05 XBEE slave/master Bluetooth module & the RS232 TTL bluetooth module. I've never played with Bluetooth stuff at all. Going by the Tero & Kimmo Karvinen book, the dongle hack looks fairly...
  11. Old Steve

    Electro magnet

    I have no idea what a marina bender is. Would it need a pair of piston-style electromagnets, like in the picture I posted? Perhaps some more info would help. A drawing or picture maybe.
  12. Old Steve

    Electro magnet

    What about using ready-made, large solenoids at each end of the clamp bar? It would take a lot of trial-and-error to design and make your own electro-magnets. I had to look at this video first, to see exactly what's required:- Something like this:-
  13. Old Steve

    I have no experience in electronics and can not figure this out!

    No problem. Keep us posted on how it progresses. You could possibly start a project log in the relevant section of the forums. (Tab at top of page.)
  14. Old Steve

    I have no experience in electronics and can not figure this out!

    1. ISP = "In System Programmer" 2. It will be used to program the Teensy, or other USB dev board. (Leonardo in this case I guess.) Since they list the Leonardo as suitable, the Arduino IDE should be fine, I would think. It's free. To upload a hex file, in the Arduino >Tools menu you select...
  15. Old Steve

    240vac capacitor type?

    I was wondering how you went. Keep that frequency as close to 50Hz as possible, or the iron transformer core will start to heat up unacceptably with higher frequencies. How does it perform for output voltage under a (very light) load? Tried yet? Don't load it too heavily or you'll easily...
  16. Old Steve

    Bad Capacitor?

    I think I see a small ring indicating a cracked solder joint around one pin below the IC, the right-hand pin of the two close to the scuff mark. Could be the problem, along with that cap. See my circle in the pic below. Also, as indicated, definitely replace that cap. The way that they're...
  17. Old Steve

    240vac capacitor type?

    So how did you go? I assume you did it without the caps?
  18. Old Steve

    Need help to draw and design circuit.

    Why two motors? That over-complicates things. Can't you just use one motor and run it in one direction to open the blinds, the other direction to close them? A DPDT relay, (or electronic H-bridge driver), could reverse the polarity of the motor connections to do this. The light-activated switch...
  19. Old Steve

    C++ - Library help - Atmel Studio 6

    I was leaving this to see if someone with more Atmel experience could/would answer. I don't have Atmel Studio, only the Arduino IDE. My copy of SPI.h, which came with Arduino, explicitly includes Arduino.h, and since it seems that you have a copy of the same version, your program will never...
  20. Old Steve

    Number of batteries

    I've thought about this a little more. My electric bike's lithium battery, (when new), had a capacity of 10Ah, (360Wh). The motor is 200W, drawing 5.6A at full throttle. (Low power, so I only ride it at full throttle.) It has a top speed of 30kph, and had a range of 30km. (Much lower now, it's...
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