Tuesday, February 2, 2010

Chapter 3 - Exercise 14 Part 3

Oops... I was wrong. Exercise 14 will be four-part series... sorry. I'm THHIIIIISSS close to finishing it.

Okay, so I've done some more with the small circuit. Yesterday I mentioned that I was adding in a switch and two 3V coin battery holders. The hard part is just keeping track of what is soldered to what... so I've been drawing a LOT of schematics and sketches.

One thing I learned from an earlier troubleshooting job (and one that got me some jabs from some commenters about not testing my circuit with the multimeter - all worthy jabs, I might add) was to test your circuit often... don't build the entire thing and then flip the switch and hope it works. So, I took their advice and hooked up the unfinished circuit at various points... one of the videos below shows a whole bunch of patch cables that I needed to test the wiring... it worked, but it's a real rats nest of wiring. (Another thing I learned from this - you can never have too many patch cords - I'm going to buy another 4 or 8.)

Now, please be kind and realize that I'm new to putting a circuit together with a soldering iron AND I'm new to laying out circuits AND I'm not 100% sure of how to wire the LED and Switch up since they won't be connected to the actual perfboard... I'm learning as I go. I think I'm going to have to use some of my braided wire (that's more flexible) so I can make all the connections. We'll see.

Anyway, here's a lot of photos and a few videos of today's work. The second video is where I've almost got the circuit 100% completed. The three solid copper wires you see poking up from underneath the perfboard - one is the + voltage, another the - voltage, and the other the R5 wire that will connect to the Anode of the LED. Hope this is making sense. You can see in the 2nd video that I've reduced the number of patch wires used in the first video and have added the switch into the mix... it works! Woo Hoo!

I've drilled the holes (side and top) and had to trim the box's left side a little so I could close the top (the switch kept it from completely closing). Another photo shows me testing that voltage is flowing - a little over 6V.

Now, hopefully no mistakes as I finish up connecting the LED and Switch wiring and close up the little box. But first, a paint job for the little box...


  1. You're right about those patch cords. I think you have room for maybe a couple more in the first video, if you try really hard. :-)

    I'm having far too much fun with this little circuit, playing with different values for capacitors and resistors on one of those teeny tiny breadboards and a 9v battery. I had it almost matching the snooze LED on my iBook.

    I've rebuilt it from scratch a few times, to test my understanding of it, and I'm getting close...

  2. Hi, Brian.

    Yes, I have to admit that I've enjoyed this exercise. Being able to modify the circuit by adding the switch and coin battery holders was fun... trying to figure it out, solder it up correctly, fit it all in the box... definitely having fun!