Search found 10 matches

by jm
Sat Mar 14, 2009 11:50 am
Forum: General Discussion
Topic: Dremel "WorkStation" ?
Replies: 26
Views: 4185

Re: Dremel "WorkStation" ?

I have the Dremel rig. It is only usefull for casual stuff. I have a 100$ Ryobi manual drillpress (made in China) which works OK. The main issue is MASS. The thing has to be made of heavy enough metal to be stable and stiff. The Ryobi weighs more than 40 lb.
by jm
Tue Apr 15, 2008 6:12 am
Forum: General Discussion
Topic: PIC to 74HC164 Another question for the experts
Replies: 28
Views: 9269

Ian,

Have you considered a 555 timer 'one shot' on the receiving end as a debouncing circuit? You do not need hi speed. The 555 stretches the pulse. You trigger on the falling edge from the 555 when transients have faded away.

If it works, 555 timers are very cheap.

jm
by jm
Mon Dec 03, 2007 6:50 pm
Forum: General Discussion
Topic: PIC to 74HC164 Another question for the experts
Replies: 28
Views: 9269

"I did change the clock input configuration. I put a 2n3904 transistor ... I then reduced the 10K pullup to a 3K pullup and it is now perfect even with high clock rates. " This seems to be the classic line driver solution. Lower the impedance to absorb transients and compensate with a device that dr...
by jm
Thu Nov 29, 2007 10:23 pm
Forum: Computer Programming
Topic: Microchip ICD 2 v. PICkit 2
Replies: 8
Views: 8330

A support engineer at Microchip told me that the Pickit2 was basically designed as a "student" version of the ICD-2. They do the same job but the ICD-2 is definitely faster in loading large programs from MPLAB. The ICD-2 supports the newer 16 bit PIC24's. The ICD-2 also has better debugging support....
by jm
Thu Nov 29, 2007 10:09 pm
Forum: Computer Programming
Topic: PICKit2, FTDI, and USB
Replies: 4
Views: 3556

MrAl, The Schmartboards work quite well. I've soldered at .5mm pitch 64pin PIC24J chip with no difficulty to an EZ board. Of course thay are intended for prototyping and are a bit pricey and perhaps oversized for a final product design. I have a Pickit2 and several PIC18F2550's. Unfortunately I have...
by jm
Thu Nov 29, 2007 9:26 pm
Forum: Computer Programming
Topic: Amel Substitution
Replies: 5
Views: 3698

foroham,

I strongly recommend you vist
http://www.avrfreaks.net/

That's were the AVR experts hangout. They have excellent forums and people are very helpful.

jm
by jm
Thu Nov 29, 2007 9:15 pm
Forum: Robotics
Topic: Recomendation for robot controller
Replies: 7
Views: 5438

Aarnat, I may be entering this conversation a little late, hopefully you see this comment. The key question centers on your prior experience. What programming languages are you confortable with? Have you used microcontrollers before? I have a Pololu Orangutan. They expect you to use the GNU C tool c...
by jm
Thu Nov 29, 2007 8:31 pm
Forum: General Discussion
Topic: New Scope Opinion
Replies: 2
Views: 1261

I've been think of getting a PC/USB based scope. Yes I'm aware of some limitations. Do either of you have any experience with them or opinions
by jm
Thu Nov 29, 2007 8:27 pm
Forum: General Discussion
Topic: Problems with Futurlec
Replies: 21
Views: 6162

MrAl, Futurlec is in Bangkok. I had a similar experience to yours, but anticipated it from dealings with Far East vendors on E-bay - great prices with flakey service. These guys seem to be honest but are not up to Western notions of customer relations plus the language/culture barrier. When I ordere...
by jm
Thu Nov 29, 2007 7:59 pm
Forum: General Discussion
Topic: PIC to 74HC164 Another question for the experts
Replies: 28
Views: 9269

What no one seems to have mentioned that a 10 foot wire between logic pins of ordinary chips is well outside their intended use. The designers expected a connection on the same circuit board - even a ribbon cable between boards can sometimes be problematic. The problem is either on your clock line o...