"Gerhard Fiedler" <[EMAIL PROTECTED]> wrote: | On 2006-08-03 06:07:31, H J van Rooyen wrote: | | > Thanks - will check it out - seems a lot of money for 555 functionality | > though.... | > | > Especially if like I, you have to pay for it with Rand - I have started | > to call the local currency Runt... | | Depending on what you're up to, you can make such a thing yourself | relatively easily. There are various possibilities, both for the | reset/restart part and for the kick-the-watchdog part. | | Since you're talking about a "555" you know at least /some/ electronics :)
*grin* You could say that - original degree was Physics and Maths ... | Two 555s (or similar): | - One wired as a retriggerable monostable and hooked up to a control line | of a serial port. It needs to be triggered regularly in order to not | trigger the second timer. | - The other wired as a monostable and hooked up to a relay that gets | activated for a certain time when it gets triggered. That relay controls | the computer power line (if you want to stay outside the case) or the reset | switch (if you want to build it into your computer). | | I don't do such things with 555s... I'm more a digital guy. There are many | options to do that, and all a lot cheaper than those boards, if you have | more time than money :) Like wise - some 25 years of amongst other things designing hardware and programming 8051 and DSP type processors in assembler... The 555 came to mind because it has been around for ever - and as someone once said (Steve Circia ?) - "My favourite programming language is solder"... - a dumb state machine implemented in hardware beats a processor every time when it comes to reliability - its just a tad inflexible... The next step above the 555 is a PIC... then you can steal power from the RS-232 line - and its a small step from "PIC" to "PIG"... Although this is getting bit off topic on a language group... ;-) Hendrik -- http://mail.python.org/mailman/listinfo/python-list
