Search found 2802 matches

by haklesup
Thu Aug 07, 2003 3:37 pm
Forum: General Discussion
Topic: This should be a simple timer circuit
Replies: 7
Views: 1070

Re: This should be a simple timer circuit

As drawn the set and reset are positive and the output goes to 12V when set (remember the set and reset are backwards on my drawing). <p>The real reason I responded was that it was pointed out to me that you would also need some sort of timer on the reset as well to account for the case where you ex...
by haklesup
Thu Aug 07, 2003 3:25 pm
Forum: General Discussion
Topic: Dakota Digital Camera $11
Replies: 5
Views: 1097

Re: Dakota Digital Camera $11

Sometimes the dumbest ideas make the most money; remember the pet rock.<p>I see it as a natural evolution of an already established market. The price is probably almost exactly the cost of such a product, so if it can be reused even one time, that constitutes a 100% profit (minus packaging and distr...
by haklesup
Wed Aug 06, 2003 6:12 pm
Forum: General Discussion
Topic: Ben Clock on Ebay!
Replies: 15
Views: 2826

Re: Ben Clock on Ebay!

Wow, If I could sell all my home brew projects for $500 bucks a pop. Ha!<p>The PCB and controller chip looks to be a good deal though. You couldn't Fab a board like that pictured for less than $150 (total for 5 pcs) and you would have to buy 5 (probably what he did). I think it would be more fun to ...
by haklesup
Wed Aug 06, 2003 5:54 pm
Forum: General Discussion
Topic: This should be a simple timer circuit
Replies: 7
Views: 1070

Re: This should be a simple timer circuit

Turn the schematic upside down and replace the ground with the battery except for RY2. It would work also if RY2 were on the other side of RY1 as well.<p>I drew it that way because most door post switches have one wire that contacts to chassis ground. To switch the hot side, you need a switch with 2...
by haklesup
Wed Aug 06, 2003 2:38 pm
Forum: General Discussion
Topic: 5 sided semi enclosures
Replies: 2
Views: 617

Re: 5 sided semi enclosures

A slope front enclosure would probably look good as a control panel. You can have the back opened up and some come with removable panels. In addition to LMB (aka LMB Heeger)also look at Bud Boxes, Serpac and Hammond enclosures. These are often stocked at many electronics retailors. I also think http...
by haklesup
Wed Aug 06, 2003 2:21 pm
Forum: General Discussion
Topic: This should be a simple timer circuit
Replies: 7
Views: 1070

Re: This should be a simple timer circuit

At the core, a flip flop would work. The circuit would be continuously powered. The door frame button would serve as the set signal and the Accessory power would serve as the reset signal. Naturally you would need some other components to scale the voltage and interface to the relay but that should ...
by haklesup
Tue Aug 05, 2003 2:37 pm
Forum: General Discussion
Topic: Any hints on how to buld pedometer?
Replies: 13
Views: 2223

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: 2223

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: 3177

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: 1145

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: 2179

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: 909

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: 820

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: 1770

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: 1463

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...