Search found 106 matches

by ecerfoglio
Wed Nov 15, 2006 1:40 pm
Forum: Robotics
Topic: Brain waves control robot
Replies: 7
Views: 5104

There is an article about Brain - Computer interface in the May 2006 Nuts & Volts (page 61)
by ecerfoglio
Wed Nov 08, 2006 4:54 am
Forum: Computer Programming
Topic: PIC oscillator frequency quite low
Replies: 17
Views: 8684

I don’t know if it is the case with Pics (as I worked programming the "old" Motorola's MC 68705 series some time ago - Yes, it was still called Motorola :shock: ), but there may be some "hidden" instruction cycles like interrupt services (even internal interrupts like timers, watchdog, etc). If yo...
by ecerfoglio
Fri Oct 20, 2006 10:38 am
Forum: Computer Programming
Topic: basic code what am I missing? IF ADC is => increase PWM
Replies: 46
Views: 23998

What is the difference between a goto or gosub statement, and an interrupt? So you would recommend interrupts over gosubs? An interrupt is trigered by an external event It may be a sensor detecting something, a switch pressed, a cero crossing in the AC voltage or even a timer that reaches its prese...
by ecerfoglio
Wed Oct 18, 2006 8:11 am
Forum: General Discussion
Topic: satalite advice needed...
Replies: 11
Views: 2209

dacflyer
why are they called irridiums ??

The system was called Iridium because it used as many satelites arround the earth as electrons in an iridium atom.

It is (was?) a satelite telephone comunications system with a constelation of low orbit satelites.
by ecerfoglio
Wed Oct 11, 2006 3:09 pm
Forum: General Discussion
Topic: Does this kind of counter IC even exist?
Replies: 18
Views: 3925

philba wrote doesn't that have the problem of not handling down shift? going from 3 to 2, for example. The CD 4029 is an UP/ DOWN counter: It has an input pin (U/D) that sets if it counts up or down. It also can count from 0 to 9 (decimal mode) or from 0 to 15 (or F if you like hexadecimal) (binary ...
by ecerfoglio
Wed Oct 11, 2006 2:58 pm
Forum: General Discussion
Topic: Does this kind of counter IC even exist?
Replies: 18
Views: 3925

You can use a syncronous counter like the cd 4029. The clock input stays (normally) high. The "Gear up" button must set (high) the up/down input and pulse the clock input low and then high (**) The "Gear down" button must RESET (set low) the up/down input and pulse the clock input low and then high ...
by ecerfoglio
Fri Sep 22, 2006 6:33 am
Forum: General Discussion
Topic: A PC costs $10 per month
Replies: 15
Views: 3236

I have a cheap DVM with AC amps. I wired it so I can measure PC current consumption. ..... 30 watts There are two reasons that can make your measurements useless: >>> Phase angle : AC Power is V x I x Cos Fi, where Fi is the phase angle between the voltage U and the current I. >>> Waveform : cheap ...
by ecerfoglio
Thu Sep 07, 2006 6:03 am
Forum: General Discussion
Topic: Power transmission lines...
Replies: 103
Views: 22605

Externet: .....an attempt I did years ago to capture the radiation from very nearby transmission lines (~120ft overhead) trying to gather at least 1 Watt of power (24/7) from such radiation to charge a battery for a commercial radio repeater at the top of a mountain with no 115V in miles around. A b...
by ecerfoglio
Thu Aug 24, 2006 1:51 pm
Forum: General Discussion
Topic: Another ICL7107 & LM34 question
Replies: 24
Views: 5945

In the data sheet that Chris has posted I see that the LM 34 outputs 0 V at 0°F (with a pull down to -V), so you don't need to add offset . (I made a mistake supposing that the LM 34 behaved identically to it's centigrade counterpart (LM 35??), which has an output proportional to the absolute tempe...
by ecerfoglio
Thu Aug 24, 2006 6:20 am
Forum: General Discussion
Topic: Another ICL7107 & LM34 question
Replies: 24
Views: 5945

The LM 34 outputs some voltage at 0°F, so you must substract that voltage (offset) in order to read 0°. You may do that with an op amp (summing amplifier, gain = 1), imputting some of the reference voltage to the - (negative) input with a voltage divider. Adjusting that voltage divider (second cal...
by ecerfoglio
Thu Aug 24, 2006 5:34 am
Forum: General Discussion
Topic: Another ICL7107 & LM34 question
Replies: 24
Views: 5945

You have to calibrate your termometer at (at least) two points (in °C the two "classical" points are 0°C (freezing watter) and 100°C (boiling watter)). With those two points you should adjust both the ** scale ** (atenuator or reference voltage) and ** offset ** . You ** MAY ** need a more accura...
by ecerfoglio
Tue Aug 22, 2006 10:20 am
Forum: General Discussion
Topic: Scanning mechanism
Replies: 11
Views: 2381

If you allow some time / distance for the device to accelerate (and decelerate), I think that Engineer1138's idea will result in a smoother movement: Just use a regular DC motor with a gear train or belt reduction to drive it, then the only control you need is a limit switch at the end of travel As ...
by ecerfoglio
Fri Aug 18, 2006 11:03 am
Forum: General Discussion
Topic: Water as a fuel.... again.
Replies: 14
Views: 2774

Dacflyer: Perhaps they don't answer your emails because you didn't send them your check A free registration can be obtained by ordering the demonstration video for $19.95. I don't know how much does it cost (in USA) to make a copy of a video and post it, but it seems that their "business" is just to...
by ecerfoglio
Fri Aug 04, 2006 10:09 am
Forum: General Discussion
Topic: Invisible infrared lamps...
Replies: 30
Views: 5448

In a slide projector, the IR filter protects not only the lenses (glass) but also the slide from the lamp’s heat.

So, if you are not using any slide it’s probably safe to keep it out - Just check if the lenses (or any plastic part near them) get too hot.
by ecerfoglio
Thu Jul 06, 2006 3:42 pm
Forum: General Discussion
Topic: another capacitor question???
Replies: 50
Views: 11091

you just asked used to help "start" a motor but you didn't say what kind of motor. JPKNHTP asumed it was a DC motor, and yes a capacitor can provide the extra current it takes while starting. bearing01 answered about (single phase) AC induction motors, which you may find in many appliances arround y...