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  1. Old Steve

    Inertial Measurment Unit (IMU) Selection !

    Thanks Dave, I'd never noticed it. I always do that the hard way too. (And I use code tags regularly, so I should have seen it. :oops: )
  2. Old Steve

    Hacking a Mattel Mindflex Headset for Brainwave Control

    I got the little LP2951 3.5V regulator nicely mounted. I hot-melt glued it to the underside of the RF module, which I'll mount upside-down. The whole thing is only a little over an inch long, so it won't be too intrusive attached to the outside of one side of the headset. I'll use Blu-Tak...
  3. Old Steve

    Inertial Measurment Unit (IMU) Selection !

    I'll second the request for subscript and superscript buttons if it's at all possible. I'm forever doing it m a n u a l l y. :) Edit: Strike-through would be nice, too. It can be used to good effect sometimes.
  4. Old Steve

    Simple power supply?

    You're not wrong there. I was out of the field for 10 years, and the combination of what I've forgotten and the advances in the intervening period has left me floundering a bit. Getting there though. These forums have helped enormously in that regard, especially forcing myself to think by...
  5. Old Steve

    How to time a watch winder

    Oh good - glad it's working now. I thought that maybe the 4013 might have died while being soldered in, and was thinking that I should have suggested an IC socket. Jaycar sell IRF540N MOSFETs. They're not real cheap though - $5.95 here, and $7.40 over there:-...
  6. Old Steve

    Problems with a Lamp Project and Dimmer Module/Switch.

    I wouldn't - that's an extremely high minimum - 240W. How often do you see 240W to 720W bulbs? (That's at 240VAC) I think it really means a maximum of 1A to 3A. (You can't really expect too much accuracy in an Amazon listing. The seller probably knows nothing about electricity, except how to...
  7. Old Steve

    How to time a watch winder

    No, a BC548 can only handle an absolute maximum 100mA. (I really drew it in by mistake originally.) Your motor's stall current will be at least several times the continuous current. An NPN transistor rated for a couple of amps is called for. A lot of transistors in that range are Darlington...
  8. Old Steve

    Problems with a Lamp Project and Dimmer Module/Switch.

    The 240VAC 50Hz dimmer that I use for my 30W el-cheapo soldering iron is 1000VA max load and 25VA min load. (I just checked the label) You should be able to get much the same in the UK. It would do the job nicely for even the 40W bulb.
  9. Old Steve

    Pic and JTAG Programmer

    I'm a habitual planner - can't help myself. :D
  10. Old Steve

    Pic and JTAG Programmer

    It only took 5 minutes to get mine running properly when I first got it. I've had it for a very long time now. It's all dependent on getting the right version of the software, from memory, and matching the version of the programmer firmware to the software version. I found a website giving good...
  11. Old Steve

    Simple power supply?

    Mike, the dropout voltage, (not usually referred to as 'delta'), is about 2.4V at 2A and 25°C. Allowing for troughs in the input voltage when it's fed by a rectified AC source, about 3V is a good safe minimum to stick to. The dropout voltage is about 2V at 25°C when the current is a little below...
  12. Old Steve

    How to time a watch winder

    I've modified the schematic, with a copy of the diagram on the bottom of the relay, and all pins numbered both on the relay diagram at the bottom and on the relay pins in the schematic. I took the name off the transistor for now, too. You'll also notice that I've drawn an 18V, 1W Zener diode...
  13. Old Steve

    Simple power supply?

    dorke, my suggestion of how to connect a centre-tapped transformer was for the future, not for this time. I was already aware that the voltage was too low to do it this time using the centre-tap. I said "for future information". (It's center-tap, too, not center-tape.)
  14. Old Steve

    How to time a watch winder

    I can just see the relay's connections. I'll draw up a diagram for you shortly. Meantime, an important question - what is the current rating of your motor? Specifically, the stall current. If you don't know, I'll show you how to measure it. (You might need to buy a 5W wire-wound resistor for...
  15. Old Steve

    Hacking a Mattel Mindflex Headset for Brainwave Control

    I got the new headset a couple of days ago. It works fine, but initially I had some problems with the signal. As I've now discovered, on the TGAM1 board theres a very tiny little jumper for setting a filter's mains rejection frequency to either 60Hz or 50Hz. Since I bought an American headset...
  16. Old Steve

    Relay Behaving Strangely

    Are you sure the receiver is on DC? A 'transformer' typically puts out AC. I guess you mean a plugpack, but they come in either AC or DC. Double-check the label carefully. Dave might be right. (Wouldn't be the first time. :) )
  17. Old Steve

    Wiring pot as voltage divider across polarities

    No problem. Glad to help.
  18. Old Steve

    Wiring pot as voltage divider across polarities

    Yep again. That should be no problem. :) Consider the logic - with the pot wiper at the 'top', it's directly connected to +5V. With the wiper at the 'bottom', it's directly connected to -5V, so 1/2 way between these, it must be 0V. You're good-to-go. ;)
  19. Old Steve

    Wiring pot as voltage divider across polarities

    Yep. You need a dual power supply, with +5V, 0V and -5V rails. Then you connect the pot beween +V and -V. You could use a small centre-tapped transformer with half-wave rectification and large reservoir caps on both rails, then a 7805 regulator for the +5V, and a 7905 for the -5V.
  20. Old Steve

    Simple power supply?

    You can't do that. It's a dead short across the secondary, and will kill it. It can be done with two separate windings, (4 wires), if you do it so that they're in phase, but not with a single, centre-tapped winding. (3 wires)
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