7 Arduino LCD display tips and tricks

Character LCD tutorial broken down by simple tips

Arduino LCD display

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.

Watch Crazy Circuits Hands-On, on YouTube

Arduino Keyboard Matrix Code and Hardware Tutorial

Here's how a keyboard works

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.

Intel_P8049_AH_controller

Original image from Deskthority Wiki. (Edited image is shown.)

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?

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Hackaday Superconference 2017 was a blast

Building stuff that matters

Hackaday Superconference 2017

Supplyframe hosted the Hackaday Superconference 2017 in Pasadena the second weekend of November. A couple of years ago I attended the first Supercon in San Francisco. It is amazing how much larger the event has grown. If you have not visited one, here’s a summary of what makes up the conference.

Five elements make up the Superconference: the talks, the learning, the people, the hacking, and the Hackaday Prize.

The Talks

Initially, I planned to write up my thoughts on the top 3 to 5 talks. Here’s the problem: they were all fantastic. Every single presentation. Instead, head over to the Hackaday YouTube channel. Currently, there is not a dedicated playlist. So look for the videos titled “Hackaday 2017.”

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Open Source Hardware Summit 2017 Recap

Open Source Hardware Summit 2017 Quote

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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picoscope 2204a on element14

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.

Full PicoScope 2204A Review on element14

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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.

In this video, I meet with Amelia Dalton of EE Journal, and we discuss these capacitor types. Mouser and EE Journal developed the video in joint with KEMET. (Previously I talked on Amelia’s Chalk Talk about SSD 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.

Learn about Aluminum Polymer 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?

Voltage Dividers as Regulators on YouTube

FleaFPGA Ohm is a crowdsource project worth considering

An awesome crowd source project is live.

FleaFPGA Ohm Prototype with case

Previously,  I wrote a FleaFPGA Introduction. This board was about the size of an Arduino Uno with some GPIO pins, a VGA, USB, SD Card, PS2 Style Port, and a USB Host connector. At the time, the Lattice Mach XO2 provided the base logic. It found some success in the emulation community (*cough* x86 *cough*.) Unlike software emulators, the FPGA emulates the actual digital logic of classic computer ICs. Also known as ASICs.

Fast forward to today, well, this week. Valentin Angelovski is at it again, but this time, with a new and improved board the size of a Raspberry Pi Zero. He’s launched an Indiegogo Campaign for the FleaFPGA Ohm. For $45 (plus a bit for shipping) you can reserve your spot for when these start shipping early next year.

As you might have noticed, I don’t often promote or comment on crowdfunded projects. My experience with crowdfunded projects has not been positive. So what makes the FleaFPGA Ohm different? Well first, I know Valentin well. Granted distance has kept us from meeting face-to-face, we talk at least once a week on IRC. I’ve been eagerly watching his progress with the FleaFPGA Ohm. Second, this isn’t his first hardware project. He’s already sold many of the original FleaFPGA boards. While there is always a risk with crowdfunded campaigns, I think the risk here is minimal–and worthwhile.

If you’re interested in advancing your hardware hacking game, FPGAs are the next step. And I think the FleaFPGA Ohm is a serious option to consider. Since you might be new to FPGAs or Valetin’s projects, I sat down to interview him for this project. (Okay, it was Google Docs, but these questions and answers are real!)

Before continuing, in disclosure, I have backed this project. However, no other endorsement or paid promotion has happened. Below here are actual answers from Valentin to questions I asked (and had.)

Back FleaFPGA Ohm on Indiegogo

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Op Amp Circuits by Bob Pease

TI (Formerly National Semiconductor)
September 2002

TI AN-31 Torn Paper

Op amps are one of the most versatile ICs in electronics. A purely analog device, they can be used for amplification, summing, integration, and a whole host of other circuits. AN-31 from Texas Instruments is 32 pages of op amp circuits. (Note: this document was created before TI acquired National Semiconductor.)

Even more amazing is that the author is Bob Pease. If you never heard of Mr. Pease, please spend a few minutes right now reading this TI page dedicated to him. His contributions to electronics are nearly immeasurable. (Sadly, he was involved in a car accident after attending the funeral of his equally famous engineering friend, Jim Williams.)

Download AN-31 from TI

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