Search found 30 matches

by John Abel
Fri Jun 08, 2007 2:07 pm
Forum: General Discussion
Topic: FPGA vs Microcontroller
Replies: 3
Views: 2452

FPGA vs Microcontroller

I am wrapping up my first digital design class which used the Nexy’s FPGA. Unfortunately the professor never got into practical applications or real world scenarios. I am curious as to how FPGA’s and similar devices like CPLD’s are used in industry, and why they would be chosen over microcontr...
by John Abel
Sun Oct 29, 2006 7:54 pm
Forum: General Discussion
Topic: Coil Direction
Replies: 2
Views: 1059

Coil Direction

If the direction of the windings in a coil is reversed the magnetic field is also reversed. For example if the windings in a motor are taken out and reoriented in the opposite direction then the motor will spin the opposite direction. Why is this? Isn't the relative direction of the current still th...
by John Abel
Sat Nov 19, 2005 11:43 pm
Forum: General Discussion
Topic: 5VDC from household light switch
Replies: 15
Views: 3348

5VDC from household light switch

I have a need for 5V DC in an area where only a light switch is handy. Is there a safe way to hook up a transformer to the wiring on the switch?
by John Abel
Wed Oct 12, 2005 9:45 pm
Forum: General Discussion
Topic: Vertical Jump tester
Replies: 14
Views: 3311

Re: Vertical Jump tester

These types of sensors (accelerometer, speaker, shock sensor) will be able to determine when the person jumps?
by John Abel
Wed Oct 12, 2005 12:17 am
Forum: General Discussion
Topic: Vertical Jump tester
Replies: 14
Views: 3311

Re: Vertical Jump tester

Where would you mount the accelerometer?
by John Abel
Tue Oct 11, 2005 11:05 pm
Forum: General Discussion
Topic: Vertical Jump tester
Replies: 14
Views: 3311

Re: Vertical Jump tester

Do you have any recommendations for a well-valued microcontroller starter kit? Also, philba, can you elaborate on your accelerometer set up? I haven’t ever worked with these devices and don’t quite follow what goes where.<p>[ October 11, 2005: Message edited by: JohnT ]</p>
by John Abel
Tue Oct 11, 2005 12:21 am
Forum: General Discussion
Topic: Vertical Jump tester
Replies: 14
Views: 3311

Vertical Jump tester

I would like to build a vertical jump tester like the one in my school’s weight room. This works by having the person to be tested step on a pressure sensitive pad. When the person jumps, the pad triggers a timer that stops when the person lands on the pad. A small computer determines the max height...
by John Abel
Mon Oct 10, 2005 12:13 am
Forum: General Discussion
Topic: I am claiming dunce of the week
Replies: 44
Views: 10621

Re: I am claiming dunce of the week

As far as the electrolysis goes I doubt that you were actually passing 20 amps through the water. If you were, you would be making hydrogen at an incredible rate; however using the electrolyte of baking soda there would be a high resistance in the water. If you were forcing this much current through...
by John Abel
Tue Sep 06, 2005 1:33 am
Forum: General Discussion
Topic: RF Signal strength to measure distance
Replies: 21
Views: 5490

Re: RF Signal strength to measure distance

I had found the AGC on the chip that handles the FM part of the radio, but it only worked for the FM. However, it doesn’t matter now because I have somehow managed to short something out and neither part of the radio seems to work (this is the second radio I have killed in this way). I’ll have to ma...
by John Abel
Sat Sep 03, 2005 11:24 pm
Forum: General Discussion
Topic: RF Signal strength to measure distance
Replies: 21
Views: 5490

Re: RF Signal strength to measure distance

Sorry jwax for my lateness, I was at a football game all of yesterday. <p>No, I’m not locked onto 1785khz. For testing purposes I am using the local oscillator of an AM radio with antenna attached as a transmitter. By adjusting the tuning capacitor of this radio I can change the transmitted frequenc...
by John Abel
Thu Sep 01, 2005 10:46 am
Forum: General Discussion
Topic: RF Signal strength to measure distance
Replies: 21
Views: 5490

Re: RF Signal strength to measure distance

Yes, this is a go-no go type of setup as you word it. I was hoping that with a low enough power transmitter there would be enough distance between “x” and “x+2” for a difference to be discerned. <p>The part number on the IC is ANZ024, which I haven’t been able to find a data sheet on. There is more ...
by John Abel
Thu Sep 01, 2005 12:00 am
Forum: General Discussion
Topic: RF Signal strength to measure distance
Replies: 21
Views: 5490

Re: RF Signal strength to measure distance

Thanks Chris for the warning, but I may have miss worded my last post. I do not intend for this to be an accurate means to measure distance over the range of 1 to 2 meters, but rather to be preset so that the measured field strength at an arbitrary distance (about 1 yard) activates the buzzer or som...
by John Abel
Wed Aug 31, 2005 9:08 pm
Forum: General Discussion
Topic: RF Signal strength to measure distance
Replies: 21
Views: 5490

Re: RF Signal strength to measure distance

Sorry for neglecting to tell you the distances I am thinking of are within a range of 1 and 2 uninterrupted yards. Thanks for the advice about the AGC. It sounds like it should be perfect. Do you have any idea where I might find the physical location of this stage on a standard radio? The radio I ha...
by John Abel
Wed Aug 31, 2005 1:07 am
Forum: General Discussion
Topic: RF Signal strength to measure distance
Replies: 21
Views: 5490

RF Signal strength to measure distance

While we are on the topic of RF, I thought you might be able to help me with an idea I’ve been brainstorming. That is to use the relative signal strength received of a low power transmitter to determine distance. <p> If a small, low powered transmitter were attached to a moving object, then a statio...
by John Abel
Fri Aug 05, 2005 6:23 pm
Forum: General Discussion
Topic: Problem with Hall sensor
Replies: 7
Views: 3450

Re: Problem with Hall sensor

Sorry Edd, I haven’t been online for a while; <p>I’ll try to answer your questions the best I can, your knowledge of the physics of this kind of thing seems far beyond my own... <p>The only reason I am using the different hall sensor is that it is easier to purchase in small quantities. In compariso...