Search found 2781 matches

by haklesup
Tue Aug 05, 2003 2:37 pm
Forum: General Discussion
Topic: Any hints on how to buld pedometer?
Replies: 13
Views: 2149

Re: Any hints on how to buld pedometer?

Check out the may issue of GPS world online at the link below. There is an article about Kinematic GPS (KGPS) getting accuracies as good as 10cm. In essence they use accelerometers to provide dead reconing input to the controller while the GPS signal is obscured<p>Other issues also have articles abo...
by haklesup
Fri Aug 01, 2003 3:21 pm
Forum: General Discussion
Topic: Any hints on how to buld pedometer?
Replies: 13
Views: 2149

Re: Any hints on how to buld pedometer?

Rick is correct, with SA turned off my recievers showed dramatic improvement in accuracy right away. That's one thing Clinton did do right. Generally the accuracy has to do with how many satellites the rcvr can see and how long you have been locked on. Military recievers use a more accurate signal c...
by haklesup
Wed Jul 30, 2003 6:41 pm
Forum: General Discussion
Topic: Circuit Power Source
Replies: 23
Views: 3077

Re: Circuit Power Source

Just to make things a little clearer about supply names. Here is the convention as I understand it.<p>Uppercase "V" means DC voltage Lowercase "v" means AC voltage<p>In the Subscript, Two Capital same letters means primary source. VDD/VSS, VCC/VEE. A lowercase subscript is incorrect but understood b...
by haklesup
Wed Jul 30, 2003 2:16 pm
Forum: General Discussion
Topic: voltage regulation for cell phone charger
Replies: 4
Views: 1108

Re: voltage regulation for cell phone charger

I believe that most car chargers do have some sort of regulating circuit given that most phones want far less than 12V to charge. Overcurrent protection is an issue also. Not so much on a good battery but you wouldnt want to burn up anything because the battery is shorted. <p>The last charger I boug...
by haklesup
Wed Jul 02, 2003 6:09 pm
Forum: General Discussion
Topic: 555 timer circuit help needed
Replies: 13
Views: 2109

Re: 555 timer circuit help needed

Check out this extensive tutorial
www.uoguelph.ca/~antoon/gadgets/555/555.html
by haklesup
Wed Jul 02, 2003 4:41 pm
Forum: General Discussion
Topic: One-shot design needed
Replies: 3
Views: 878

One-shot design needed

I need to design a simple circuit that will give me a 20us square pulse with variable amplitude (about 0V to 1V and at least 1mA). The event will be triggered by a button push.<p>I am familiar with variable pulse-width designs using the 555 but I am not sure how to vary the output amplitude without ...
by haklesup
Sun May 25, 2003 12:16 pm
Forum: General Discussion
Topic: Reducing TV Volume
Replies: 3
Views: 783

Re: Reducing TV Volume

If you are correct that the signal level (volume) is too high and causing distortion the solution would be an op-amp set up for gain of less than 1 and having sufficient bandwidth (they have these for car audio in stores). However, I would expect clipping from too high of a level and this would soun...
by haklesup
Thu May 22, 2003 12:11 pm
Forum: General Discussion
Topic: TTL interface
Replies: 10
Views: 1714

Re: TTL interface

Sounds like a logic "state machine" would work here. You should be able to make one using a hand full of flip flops and logic gates. the design method can be learned from any good logic design book but let me try to set the stage:<p>Imagine a black box with inputs outputs and a clock input.<p>Your i...
by haklesup
Wed May 21, 2003 12:50 pm
Forum: General Discussion
Topic: two quickie questions;
Replies: 6
Views: 1406

Re: two quickie questions;

I don't know specifically about the organ but my experience says that the parts are generally worth more than the whole, on paper. Once you start selling them, the extra effort of finding additional buyers, the time and cost for shipping more items and the effort to find better venues to sell may st...
by haklesup
Mon May 19, 2003 11:37 am
Forum: General Discussion
Topic: TTL interface
Replies: 10
Views: 1714

Re: TTL interface

By optical interface, do you mean a digital interface for the picture (optical) data or did you actually opto-isolate the signals between the camera and printer? By TTL Logic do you mean that the interface is strictly 5V?<p>Sounds like a solution using only cables (wire to wire handshaking)is unlikl...
by haklesup
Mon May 12, 2003 11:00 am
Forum: General Discussion
Topic: Car stereo buzz problem
Replies: 8
Views: 1652

Re: Car stereo buzz problem

Buzzing is one of the most common problems in car sterio installations. especially when connecting a head unit to an amplifier, in your case it is a CD and the amplifier is the head unit. <p>In any case, it sounds like ground loop noise. You can either make absolutly sure that the CD power supply (c...
by haklesup
Tue May 06, 2003 10:15 pm
Forum: General Discussion
Topic: Micro electronics, micro wiring, terminals...?
Replies: 1
Views: 563

Re: Micro electronics, micro wiring, terminals...?

How many conductors and what is the lead pitch (how far apart are the pins) on this "Flex Cable"?<p>You can find these cables in lots of computer equipment like printers and CD drives but if the number of conductors and lead pitch don't match up then it would be difficult to mate them. YOu can find ...
by haklesup
Tue May 06, 2003 7:51 pm
Forum: General Discussion
Topic: Transistor power rating(newbie)
Replies: 1
Views: 510

Re: Transistor power rating(newbie)

It has to do with the voltage drop across the xistor and the load. Take this example:<p>Imagine a transiator (E- GND) in series with a coil with a 120ohm resistance. (C to load, B to control ckt).<p>If the power in the transistor is P=Ic*Vce. Bias it at 3V and 100mA (whatever hypothetical xistor you...
by haklesup
Mon May 05, 2003 12:52 pm
Forum: General Discussion
Topic: Moving cable sensing
Replies: 3
Views: 673

Re: Moving cable sensing

It's difficult to tell how much contrast two colors will have when viewed in IR light. The paint you used may not be good enough. Try glitter nail polish or some other paint with high reflective qualities. Or use a carbon black for high contrast. Use a lighter to make soot on a piece of Al foil then...
by haklesup
Fri May 02, 2003 12:20 pm
Forum: General Discussion
Topic: Moving cable sensing
Replies: 3
Views: 673

Re: Moving cable sensing

I think you are on the right track by putting black and white contrasting bands on the cord. This is essentially a linear optical encoder.<p>The IR LED/Detector depends on line of sight between the two parts (transmitted light). Since the cord blocks the beam all the time, it would not work. You nee...