tag:blogger.com,1999:blog-6615160292280278140.post159105000968696086..comments2024-03-28T08:07:01.529-04:00Comments on Hands On - Make: Electronics: Chapter 4 - Exercise 18 CompletedJames Floyd Kelly (Jim)http://www.blogger.com/profile/13876934942928389738noreply@blogger.comBlogger2125tag:blogger.com,1999:blog-6615160292280278140.post-7199507439419351922014-05-23T07:40:42.151-04:002014-05-23T07:40:42.151-04:00.on chapter 18 page 180 under Enhancements, bullet....on chapter 18 page 180 under Enhancements, bulletpoint 1 says that with a 555timer you can power in and have the on ready mode, tried connecting the Timmer on everyway the book show, using output 3 to pin 15 of IC1 but to send a negative pulse to pin 2 IC6 I connected to pin 6,..didnt work. Could you show me a schematic for this connection, thank youAnonymoushttps://www.blogger.com/profile/11036419232311341080noreply@blogger.comtag:blogger.com,1999:blog-6615160292280278140.post-61324078894501765532014-03-30T20:58:28.309-04:002014-03-30T20:58:28.309-04:00I had a trouble with the start switch at first. I ...I had a trouble with the start switch at first. I used my logic probe to test both the output pin on IC7 and the reset pin on IC6. I confirmed that the output on IC7 was going high for about 4 seconds, then going back low again. The reset pin on IC6 was high with a quick pulse low (showed up as a "pulse" on the logic probe, not a transition from high to low). This is exactly the behavior expected, but it still wasn't starting the timer back up. Turns out there's a typo in Figured 4-41 on page 178 (already in the errata... gotta learn to check there sooner). There are two resistors labeled R10 that the caption says should be 1K. Both of the R10 resistors should actually be 10K.<br /><br />I think the 1K resistors were letting capacitor C4 charge back up too quickly after the positive pulse from IC7. This made the drop in voltage on pin 4 of IC6 too quick for it to register. With the 10K resistors, C4 will take a little longer to charge, dropping the voltage on pin 4 of IC6 for a little bit longer. I think that tiny bit of extra time is what let the reset start working.chaulkyhttps://www.blogger.com/profile/03416827071198524226noreply@blogger.com