One of the last significant steps in a project is designing the custom PCB. This stage means creating a DIY Arduino board that is custom to the application. Two examples of my past projects are BinBoo, a Binary Clock, and Open Vapors, my reflow oven controller.
While working on a project for a friend, I got to thinking; it would be nice to have a checklist for circuit elements to include on a DIY Arduino board. In the early days, I forgot to add a filter cap to AREF, for example.
These tips are based on an 8-bit AVR design, like the ATmega328p chip. You could apply these tips to other 8-bit AVRs. Until now, I have not designed a custom board around a 32-Bit/ARM board. Though at only $16, I would be tempted to just solder the Teensy module directly to my finished board.
Below is a written list of items for a DIY Arduino checklist. If you’d like to see me design this board in KiCad, check out this AddOhms Tutorial.
The next AddOhms Tutorial is how to design a DIY Arduino board. What are the elements you need to include in your own circuit design? While editing the video, I ended up on this frame. It looked to me like I was praying. (At one point I was having serious technical issues with my equipment. But it is unrelated to that frame!) On Twitter, my friend Philip had a different take.
Question: What caption comes to mind when you see this picture? Leave a comment with yours. You can leave a comment by clicking here.
If you can’t think of a caption, maybe you can help with a different question. What your favorite LM741 op amp alternative? I’ve been working on some tutorials and videos on op-amps. I’d like to incorporate something other than the old stand-by.
Project wise I got my RetroPie SNES build completed, using an old Super Famicom case. This case is one I bought in Japan for 500 yen (about $5.) This work also led me to discuss voltage divider circuits. And I looked at a couple of scopes.
In case you missed it, here is what you as a reader found interesting over the past year.
When I started working on Open Vapors, I thought the stumbling point would be the PID algorithm or safe AC line control. However, it turned out; I spent a significant amount of time understanding how to print to the Arduino LCD display correctly.
As I dig into my latest project, the lessons I learned back then are coming back to me. Here are 7 tips for driving an Arduino LCD display, like one with 2×20 or 4×20 characters.
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In April 2017 I backed a project on Kickstarter called “Crazy Circuits.” It looked like a cool concept that was well developed, so I even included it in the Baldengineer Newsletter. I do not typically promote Kickstarter projects–unless they are exceptional in some way. I liked the concept of circuits that worked with existing LEGO-sized boards and pieces. Their shipping was a couple of months off, but nothing compared to some Kickstarter disasters. I received my Crazy Circuits kit in November, compared to the promised September.
The product concept is simple enough I could not put the time into a full write-up or an AddOhms Tutorial video. So, instead, I featured it on an AddOhms Live stream. For example, to connect an LED to a battery, just snap in some conductive “tape.” In the video, I am building my first two circuits ever. I do think the ribbon takes a bit of practice. However, as I said earlier, I like that it adapts to existing LEGO bricks rather well.
If you know someone interested in electronics but afraid of soldering, I think the Crazy Circuits kits are an interesting option. The case they come in is nice. (I know, strange thing to throw out there, but I do like the sorting case.)
After the hands-on, which lasts about 30 minutes, I answer viewer questions. These questions cover op-amps, LEDs, and capacitors.
As a kid, I got the book “Upgrading and Repairing PCs.” (Now in its 22nd edition.) It was the first book to explain to me the PC architecture. I considered, how were there so few pins on an AT-style keyboard connector when there were 101 keys on the keyboard? That is when I first learned about the keyboard matrix.
The keyboard matrix itself did not amaze me, but instead the idea there was an entirely separate 8-bit microcontroller inside of the keyboard. Early keyboards may have used the P8049AH, which, there is still some stock available to purchase. I was fascinated with the idea an entire computer was necessary to run the keyboard, to use my “real” computer. Why did it take something as complicated as a microcontroller?
This year Denver hosted the 2017 Open Source Hardware Summit. It’s a one-day seminar with talks, demos, and a couple of drinks. The day after the official show Sparkfun and Aleph Objects hosted tours of their facilities. The combination of events made for a fantastic immersion into open source hardware.
There were many talks and demos setup during the summit. Here are three that caught my attention. Please note, this is not to rate or judge the quality of anyone’s work. Simply, a couple of weeks later these are the three talks that stuck with me.
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Previously, I wrote up a hands-on with the PicoScope 2204A. At the time I only spent a few minutes with the device. I used it to “debug” an I2C bus between an Arduino and OLED screen. Since that initial hands-on, I’ve used the PicoScope in my lab. Most notably, I hosted another “hands-on” via an AddOhms Live Stream. I used it for another live stream where I talked about op-amps. Unfortunately, the video isn’t watchable due to some technical difficulties.
However, both of those activities plus debugging a new project I’m working on, gave me a chance to understand this humble USB-based oscilloscope. Now that I’ve held well over a month of bench time with it, I can say I am happy with the 2204A. If you’re looking for a low-cost, but fully featured oscilloscope, give the PicoScope 2204A a consideration. For more details on why I feel that way, click the button below to see my full write review on element14.
What are aluminum polymer capacitors? These are a solid type of capacitor that replaces the liquid electrolyte with a solid polymer material. Sometimes you might hear these capacitors called “organic aluminum.” Technically, they are still “electrolytic” capacitors. However, the colloquial term of “aluminum electrolytic” refers to the traditional wet electrolyte-based capacitors.
For me, the release of this video is bittersweet. It is one of my last projects before my departure from KEMET. However, I am excited to talk about aluminum polymer capacitors because they represent one of the “newer” technologies when it comes to capacitors.
Difference between Aluminum Polymer Capacitors and Aluminum Electrolytics
As mentioned, the key difference between the capacitor types is the electrolyte. In a traditional aluminum electrolytic, there is an electrolyte that connects the cathode plate of the capacitor to the cathode electrode. In a polymer capacitor, a solid conductive polymer material replaces the wet electrolyte. The most common polymer material is PEDOT. The use of this material provides an exceptionally low ESR which makes the capacitors can handle more ripple current. Also, because there is no electrolyte to “dry up” or “wear out,” the operational lifetime of these capacitors is much longer. Overall, aluminum polymer capacitors are an excellent alternative to traditional electrolytics.