Common question that comes up about pull-up resistors: what value do you pick and why not just use a piece of wire? In this follow-up electronics tutorial, the bald engineer looks at how to pick a pull-up resistor value. Note that while focused on pull-up everything said in this video would apply to pull-down as well.
Autodesk released EAGLE 9. This new version continues the improvement that Autodesk has been providing since acquiring the infamous ECAD tool. There are three areas I look at in this AddOhms Livestream.
How I looked at EAGLE 9
In the beginning, I use an old training class I wrote about five years ago when I was using EAGLE daily. It shows how to design a 555 flashing circuit from schematic to PCB. A follow-on class taught how to mill the PCB on a Shopbot. I might update the course and release it if I have time. The exercise class helps me find some surprises with EAGLE’s incremental improvements.
After that, I check out three new features. I also looked at the “Design Blocks” stuff which is a way to incorporate completed schematics like the Adafruit PowerBoost circuit. I need to come back and look at that function again later. Also, I am not positive, but I think that feature was introduced before 9.
1. Quick Routing
The quick routing reminds of the old “follow me” option. You can select individual airwires, entire nets, or multiple signals to route interactively. Unlike the Autorouter, which routes the board as the whole. In the video, I build a simple 555-based PCB. I couldn’t try out routing multiple signals, like address and data for DDR memory. The value I see most from this feature is selectively routing your critical signals and then quick routing the remaining non-critical nets.
2. Device Manager
This informational window provides a clean break-down of many pieces of data. Need to know what layers a footprint use? How about the length of an entire net? In the video, I show that you can use this feature to verify all of your passive components have the same package style. The information is all there, Device Manager brings it to your attention.
Spoiler Alert: I really like the Breakout Feature. (For those that say I don’t smile in videos, I did this time.) Long story short, this is a shortcut to expand all of the pins for an IC. A great example is in the AddOhms Pyramiduino DIY PCB episode. In the beginning, you can see my time lapse as I break out each of the GPIO pins. That can happen in EAGLE now with a single click.
Check it out
Have you had a chance to check out EAGLE 9 yet? If so, what are your thoughts?
Continuing the DIY Arduino tutorial series, this AddOhms episode shows how to create a PCB in KiCad. I make a joke that the original design was a rectangle, which I found boring and pointless. So instead, I designed a triangle to give the board 3 points. Get it? Puns! I am calling it the Pryamiduino. To be honest, I found not having a constraint to be a problem. By forcing a specific board size and shape, many decisions were more manageable.
First design – Boring!
In the end, the video ended up more edited than I planned. KiCad is just so finicky and crashy that I could not make a coherent start to finish tutorial. At least, I could not work with a board at this level of complexity. Something simple like a 555 flasher would be easier to show from start to finish. I am planning some immediate follow-ups with quick tips on using KiCad. It is a frustrating suite of applications, but the results can be quite nice.
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.
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.
Can you use voltage dividers as regulators? What if you add a Zener Diode? In this AddOhms episode, I show what happens when you try to power a complex circuit like an ESP8266 with a voltage divider instead of a regulator. (Spoiler: Get a voltage regulator.) This video tutorial is related to a write up I did recently on Zener Diodes. For questions or comments visit the AddOhms Discussion Forum.
Behind the scenes
A significant change for this AddOhms Episode is that I moved from Final Cut Pro X to Premiere Pro. I also shot the entire video in 4K, even though the output is 1080p. Animations were still done as 1080p compositions. One snag I ran into, the color corrections I applied in PPro, didn’t seem to get exported. You might notice when the breadboard is on screen, it has a very slight yellow tint to it.
I’ve been changing how I produce the videos. It’s shortening the cycle time. The key is that I’m not trying to animate every scene. The amount of work involved is just too much. I animate practically every frame. So in a 6-minute video, that’s just too much.
By the way, there are two easter eggs in this episode. Can you find them?
Sunday September 24, 2017, I will host the 2nd live stream of AddOhms. My first live stream was a test for the technology pieces. I’ve made some refinements and am giving it a second try. For that reason, I’m keeping the topic really simple.
The Agenda for the Live Stream is:
News (3 stories or projects that I found interesting)
Op Amps with the XL741
Whatever surprises pop-up.
In the livestream, I’ll be talking about inverting and non-inverting circuits using an op-amp. But I am not going to use just ANY op-amp. I’ll be using the MASSIVE XL741! (I did a review of Evil Mad Scientist Lab’s XL741 in the past.)