Displays We Love Hacking: SPI And I2C

December 21, 2023 by Arya Voronova 17 Comments

I’ve talked about HD44780 displays before – they’ve been a mainstay of microcontroller projects for literal decades. In the modern hobbyist world, there’s an elephant in the room – the sheer variety of I2C and SPI displays you can buy. They’re all so different, some are LCD and some are OLED, some have a touchscreen layer and some don’t, some come on breakouts and some are a bare panel. No matter which one you pick, there are things you deserve to know.

These displays are exceptionally microcontroller-friendly, they require hardly any GPIOs, or none extra if you already use I2C. They’re also unbelievably cheap, and so tiny that you can comfortably add one even if you’re hurting for space. Sure, they require more RAM and a more sophisticated software library than HD44780, but with modern microcontrollers, this is no problem at all. As a result, you will see them in almost every project under the sun.

What do you need for those? What are the requirements to operate one? What kind of tricks can you use with them? Let’s go through the main aspects.

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Mini DarkTower Clone Restores Your Childhood

April 15, 2022 by Kristina Panos 8 Comments

Remember DarkTower? No? Well, it’s a really cool combination board game, RPG, and computer game from 1981. Orson Welles pimped it on TV and explained it thusly: “collect three keys, lay siege to the tower, and defeat the enemy within”. The Tower itself was a battery-powered computer on lazy Susan that showed numbers on a couple of 7-segment displays, pictures via three carousels, and had a 12-button keypad. Thanks to a lawsuit, few copies remain, and even fewer of them are in working condition.

Working copies of DarkTower go for hundreds online, but who can afford such an extravagance when these 40+ year old towers are prone to battery leakage and loose connections? Certainly not [Mighty Studios], who was hoping to give the gift of DarkTower to a friend and decided to build a mini reproduction instead. Fortunately for us, the project is completely open source. You can check out the build video below, which has plenty of links, including one that goes to the code.

In this day and age, it doesn’t take much to reproduce the internals of the Tower. [Mighty Studios] pulled it off with a Feather S2, a 320 x 420 TFT LCD screen, a speaker, and a couple of momentary buttons. The screen can show all the pictures, (which were only displayed one at a time in the original game anyway), any necessary numbers, and all the requisite menu options.

[Mighty Studios] got mighty lucky when it came to the case, as [Stinkevil] had already created a dice tower version and put it on Thingiverse. After a bit of tweaking and some hole-punching, [Mighty Studios] had a mini tower scaled to the Feather S2 with just enough room to stuff in all the components and wires. Between a PDF of the original rule book and someone’s Java version of the game, [Mighty Studios] had plenty to use as a guide for programming in the rule set before mailing it off to their friend. We have to admit, we’re pretty jealous.

Don’t want to amass an army and conquer evil forces? There are all types of board games you could emulate with a microcontroller.

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Make Christmas Commercial Again With This Tiny TV Ornament

December 11, 2017 by Dan Maloney 11 Comments

Readers of a certain age will remember a time when the Christmas season in the US officially kicked off after Thanksgiving. That was when advertisers began saturation bombing the communal mind with holiday-themed TV commercials night and day. Broadcast TV no longer holds sway like it did back then, and advertisers now start their onslaught in September, but you can put a little retro-commercialism back to Christmas with this 90s Christmas commercial-playing ornament for your tree.

The idea came to [SeanHodgins] after stumbling upon a collection of Christmas commercials from the 1990s on YouTube. With his content identified, he set about building a tree-worthy display from a Pi Zero W and a TFT LCD display. An audio amp and tiny speaker from an old tablet and a LiPo battery and charger form the guts of [Sean]’s TV, which were stuffed into a 3D-printed TV case, appropriately modeled after the TV from The Simpsons. The small fresnel lens that mimics the curved screens of yore is a nice touch. The software has some neat tricks, such as an HTTP server that accepts the slug of a YouTube video, fetches the MP4, and automatically plays it. We prefer our Christmas tree ornaments a little quieter, so a volume control would have been nice, but aside from that this looks like a ton of fun.

This isn’t [Sean]’s first foray into tricked-out ornaments, of course; readers might recall his IoT cheer-measuring Christmas ornaments from last season.

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Everyone Loves Faster ESP8266 TFT Libs

April 8, 2017 by Elliot Williams 24 Comments

Reader [Jasper] writes in with glowing praise for the TFT_eSPI library for the ESP8266 and the various cheap 480×320 TFT displays (ILI9341, ILI9163, ST7735, S6D02A1, etc.) that support SPI mode. It’s a drop-in replacement for the Adafruit GFX and driver libraries, so you don’t need to rework your code to take advantage of it. If you’re looking to drive an LCD screen with an ESP8266 and Arduino, check this out for sure.

As a testbed, [Jasper] ported his Tick Tock Timer project over to the new library. He got a sevenfold increase in draw speed, going from 500 ms to 76 ms. That’s the difference between a refresh that’s visibly slow, and one that looks like it happens instantly. Sweet.

Improving software infrastructure isn’t one of the sexiest or most visible hacks, but it can touch the lives of many hackers. How many projects have we featured with an ESP8266 and a screen? Thanks, [Bodmer] for the good work, and [Jasper] for bringing it to our attention.

Own The Night With This Open Source Night Vision Monocular

February 23, 2017 by Dan Maloney 29 Comments

If you’ve always wanted to see in the dark but haven’t been able to score those perfect Soviet-era military surplus night vision goggles, you may be in luck. Now there’s an open-source night vision monocular that you can build to keep tabs on the nighttime goings-on in your yard.

Where this project stands out is not so much the electronics — it’s really just a simple CCD camera module with the IR pass filter removed, an LCD screen to display the image, and a big fat IR LED to throw some light around. [MattGyver92] seemed to put most of his effort into designing a great case for the monocular, at the price of 25 hours of 3D printer time. The main body of the case is nicely contoured, the eyepiece has a comfortable eyecup printed in NinjaFlex, and the camera is mounted on a ball-and-socket gimbal to allow fine off-axis angle adjustments. That comes in handy to eliminate parallax errors while using the monocular for nighttime walks with both eyes open. One quibble: the faux mil-surp look is achieved with a green filter over the TFT LCD panel. We wonder if somehow eliminating the red and blue channels from the camera might not have been slightly more elegant.

Overall, though, we like the way this project came out, and we also like the way [MattGyver92] bucked the Fusion 360 trend and used SketchUp to design the case. But if walking around at night with a monocular at your face isn’t appealing, you can always try biohacking yourself to achieve night vision.

The BlueOkiris Gameduino Console

August 1, 2014 by Matt Terndrup 2 Comments

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[Dylan] created an easy to make gaming console with an Arduino Uno, a makeshift button, an analog stick, and a TFT LCD touchscreen shield. Plus, he fashioned together a simple button with some duct tape.

So far, he has made 2 games. One is the infamous Pong. The other is a ‘Guess the Number’ type experience. The whole project is run within the code, and does not access the bootloader directly like you would with 2boots or a regular Gameduino adapter.

Build instructions can be found on [Dylan]’s hackaday.io project page (linked above). Essentially, all that is needed is to gather up the supplies, then take the button and analog stick and complete a circuit, fitting the open wires into the slots at digital pin 9. Solder the wires in place and connect ground to ground, 5v to 5v, x to A4, and y to A5. Add the TFT shield, insert a micro SD card, and upload a game.

To see it in action, check out the video after the break:

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The Lightgame Project: A Multiplayer Arduino Game

May 28, 2014 by Nick Conn 3 Comments

lightgame_3 Summer is upon us. The Lightgame Project is a multiplayer reaction time based game built around the Arduino. It’s a perfect rainy day project for those restless kids (and adults!). Designed by two undergraduate students [Efstathios] and [Thodoris] for a semester long project, all the hard work has already been done for you.

There are tons of reasons we love games that you can build yourself. For one, it’s an amazing way to get children interested in hobby electronics, making, and hacking. Especially when they can play the game with (and show off to) their friends. Another reason is that it is a perfect way to share your project with friends and family, showcasing what you have been learning. The game is based on your reaction time and whether or not you press your button when another players color is shown. The project is built around two Arduinos connected via I2C. The master handles the mechanics of the game, while the slave handles the TFT LCD and playing music through a buzzer.

I2C is a great communication protocol to be familiar with and this is a great project to give it a try. [Efstathios] and [Thodoris] did a great job writing up their post, plus they included all the code and schematics needed to build your own. It would be great to see more university professors foster open source hardware and software with their students. A special thanks goes out to [Dr. Dasygenis] for submitting his student’s work to us!

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