Re: BASICS!-how can i make this simple recorder loop?


Now you need to cobble together a 555 with an NPN transistor like a
2N3904 to do this (view in fixed font or M$ Notepad):

|
| VCC VCC VCC
| + + +
| | | |
| .-. | |
| 150K| | .---o----o---.
| | | | 8 4 |
| '-' | |
| | | |
| o-----o7 |
| | | | Wire 1
| .-. | LMC555 | .------->
| 10K| | | | |
| | | .--o6 | |
| '-' | | | ___ |/
| | | | 3o---|___|--| 2N3904
| o--o--o2 | 22K |>
| +| | 1 5 | | Wire 2
| --- '---o----o---' o------->
| --- | |
| 100uF| === ===
| === GND GND
| GND
|
(created by AACircuit v1.28.6 beta 04/19/05www.tech-chat.de)

im not sure that i unerstand this diagram, but i managed to find a
great explanation of these 555 ics (for other complete beginners, go
here: http://www.uoguelph.ca/~antoon/gadgets/555/555.html)

im going to try and use the information you gave me (thank you thank
you thank you!) and combine it with the simpler diagrams in the link.
and having looked at the link above, im beginning to get a better
understanding of your diagram.

thanks again,

a-


This should turn on the transistor (and restart the ISD chip about once
every 10.5 seconds or so. Depending, it might be better to use a 180K
or 220K resistor in place of the 150K -- your call. Don't make it too
close -- cap values drift over time and with temperature.

The easiest way to supply power would be to just use an external 9V
alkaline battery for the 555/transistor circuit. That way you don't
drain the little coin cells, which look like they might be a little
difficult to replace.

Good luck
Chris

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