I am working on a larger projected and have decided the Arduino ATMEGA328 (which seem to be hard to find in stock online) would be the best choice for the project. Seeing as how the project is going to utilize 7-Segment multi-digit displays (common cathode), I knew I had to find a LED driver, no other realistic way to drive the displays. Anyhow, I picked up some LED drivers from one of my favorite companies, MAXIM. I chose the MAX7219 as it's well documented and works with the existing LED driver Arduino library. This prototype was to ensure I had everything working as I would have expected. In this prototype, I utilized a fixed Rset value. I'll use a trim pot in my other project (which I'll write up next weekend). If you have any questions on wiring up one of these LED drivers with Arduino, check this site out and this one.
I've finally gotten around to publishing my first instructable! Have a read and as always, let me know what you think!
For some time now, I've been educating myself on the basics of electrical engineering in a somewhat unorthodox manor, the internet! I've always been fascinated by the application of theory and creating tangible results from the wildest of concepts, so it was an obvious path to end up working with electronics.
Today it occurred to me that I have learned so much from the internet community of folks freely sharing their knowledge, that I needed to talk about the Creative Commons License. Knowledge should be free and it should be shared with anyone willing to take it! This is why I’m releasing all of my future work under the “Creative Commons Attribution-Noncommercial-Share Alike 3.0 Unported License”. Quite a mouthful huh? Well, if you don’t already know what this license is, you need to read THIS. I strongly encourage everyone to follow in these footsteps and openly give away your knowledge! You can’t take it with you after all…
This work by Jay Collett is licensed under a Creative Commons Attribution-Noncommercial-Share Alike 3.0 United States License.
Permissions beyond the scope of this license may be available here.
I finally got my order in from SparkFun.com this morning and couldn't wait to try my hand at building out my Arduino boards. I've talked about them before here. The challenge was the USB to Serial chip which is a SMD chip. With my new iron and some good quality solder wick, I was able to get them on the first time with little to no effort. The iron is a HUGE leap forward for me. I can't rave enough about how much I love it, granted I'm comparing it to my Radio Shack iron which is lovingly called a "fire starter" by most. Anyhow, built these boards and plugged them in to see if all was good, whatta ya know, right off the bat I was able to upload sketches to them both! I've got a few tweaks I'm going to make to this design tho, I"m going to add SMD leds for USB RX/TX activity and rearrange the boards just a bit. If you are wondering why on earth I'd have a vertical USB plug, it's because I plan on using these boards for another project and that's the orientation I wanted. You can easily switch the part out for the vertical one in Eagle. If you want the schematic or board files, they are attached to my previous post here. As for costs of these, I've got less than ~$15 US in each.
So, I decided after ruining a few boards that I'd research soldering SMD parts to see how I could possibly be messing up these boards so badly. After all, it never crossed my mind that it would be this difficult to solder SMD chips...Once again (I know, I know, I praise these guys too much), I ran upon a series of tutorials on SMD soldering from those fantastic guys over at SparkFun.com. They provided invaluable information on exactly what I was doing wrong as well as how I could make my designs and my life much simpler my learning the fine art of SMD soldering. I bit the bullet and picked up a nice analog soldering iron, my radio shack special was not gonna cut it any longer. They sell a nice Aoyue 2901 for ~$79, more than other online sellers but I'm fine with giving them a few dollars more for supporting the communality as they do! I picked it up with some other essentials, like de-solder braid and tweezers...I should have the order Thursday and I can't wait to see how easily SMD soldering can be with the right knowledge and tools! I'm also adding the Aoyue 968 SMD rework system to my wish-list! At any rate, I'll be added those seemingly out of reach SMD discrete components to my designs going forward!
I've been consumed lately with saving power with my designs and I decided to focus my obsession on my new "FakeFireLEDDriver" design I got inspired to build from this example. I knew that I wanted to hand out Halloween gifts, in this case Jack-O-Lantern fake fire boards to my family who always pacify my obsessions du-jour. I knew that the first version worked and worked quite well, but I couldn't stand the thought that it was definitely a battery hog. Much could be done to improve upon it's energy consumption. Knowing that AVRs are known for their power saving design, I set out to figure out how to squeeze out more efficiency from this design. What is attached below is my first attempt at power savings with the "FakeFireLEDDriver" design. I've basically implemented a WDT (Watchdog Timer) to tell the system to wake up (if the system is asleep) every ~8 seconds and check the photocell, if it's dark, flicker away, if not, go back to sleep. This simple change in logic should save considerable energy. My next step is to only give power to the photocell during that check, which is about as much energy as I can see saving with this design. Check out the attached code and as always, feedback is most welcomed!