IR Detective Eases Development With Compact Decoding

April 27, 2018 by Donald Papp 13 Comments

Hardware development often involves working with things that can’t be directly perceived, which is one reason good development tools are so important. In appreciation of this, [David Johnson-Davies] created the IR Remote Control Detective to simplify working with IR signals. While IR remote controls are commonplace, there are a number of different protocols and encoding methods in use across different brands. The IR Detective takes care of all of that with three main components, none of which are particularly expensive. To use the decoder, one simply points an IR remote at the unit and presses one of the buttons. The IR Detective will identify the protocol, decode the signal, and display the address and command related to the key that was pressed. The unit doesn’t consist of much more than an ATtiny85 microcontroller, a small OLED display, and an IR receiver unit. The IR receiver used is intended for a 38 kHz carrier, but such receivers can and do respond to signals outside this frequency, although they do so at a reduced range.

As a result, not only is the unit useful for decoding IR or verifying that correct signals are being generated, but the small size and low cost means it could easily be used as a general purpose receiver to add IR remote control to other devices. It’s also halfway to bridging IR to something else, like this WiFi-IR bridge which not only interfaces to legacy hardware, but does it across WiFi to boot.

Former Smoker Now Pats Pockets For Motivation

April 24, 2018 by Kristina Panos 13 Comments

It’s hard to quit smoking. Trust us, we know. Half the battle is wanting to quit in the first place. Once you do, the other half is mostly fighting with yourself until enough time goes by that food tastes better, and life looks longer.

[Danko] recently quit smoking. And because idle hands are Big Tobacco’s tools, he kept himself busy through those torturous first few days by building a piece of pocket-sized motivation. This little board’s main purpose is to help him root for himself by showing the time elapsed since his final cigarette, the number of cigarettes he has avoided, and all the money he’s saved since then. At the press of a button, he can reflect on the exact moment he took the plunge into Cold Turkey Lake.

Sure, there are apps that’ll do the same thing. But anyone who’s ever tried to quit smoking knows how important it is to stay busy every minute while your brain deals with the lack of toxins. It runs on an ATtiny85 and a DS1307 RTC chip. Looks to us like [Danko] adapted a board from a different project, and we love it when that’s a possibility.

Not a smoker? Good for you. The next hardest thing humans motivate themselves to do is exercise. That’s a lifelong battle that can definitely be improved with some gamification.

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Racing The Beam On An ATtiny

March 8, 2018 by Brian Benchoff 77 Comments

For the last thirty or so years, the demoscene community has been stretching what is possible on computer systems with carefully crafted assembly and weird graphical tricks. What’s more impressive is hand-crafted assembly code pushing the boundaries of what is possible using a microcontroller. Especially small microcontrollers. In what is probably the most impressive demo we’ve seen use this particular chip, [AtomicZombie] is bouncing boing balls on an ATtiny85. It’s an impressive bit of assembly work, and the video is some of the most impressive stuff we’ve ever seen on a microcontroller this small.

First, the hardware. This is just about the simplest circuit you can build with an ATtiny85. There’s an ISP header, a VGA port with a few resistors, a 1/8″ audio jack driven by a transistor, and most importantly, a 40MHz crystal. Yes, this ATtiny is running far faster than the official spec allows, but it works.

The firmware for this build is entirely assembly, but surprisingly not that much assembly. It’s even less if you exclude the hundred or so lines of definitions for the Boing balls.

The resulting code spits out VGA at 204×240 resolution and sixty frames per second. These are eight color sprites, with Alpha, and there’s four-channel sound. This is, as far as we’re aware, the limit of what an ATtiny can do, and an excellent example of what you can do if you buckle down and write some really tight assembly.

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Tiny Function Generator On The ATtiny85, Complete With OLED

March 2, 2018 by Donald Papp 4 Comments

It’s easy to have a soft spot for “mini” yet perfectly functional versions of electronic workbench tools, like [David Johnson-Davies]’s Tiny Function Generator which uses an ATtiny85 to generate different waveforms at up to 5 kHz. It’s complete with a small OLED display to show the waveform and frequency selected. One of the reasons projects like this are great is not only because they tend to show off some software, but because they are great examples of the kind of fantastic possibilities that are open to anyone who wants to develop an idea. For example, it wasn’t all that long ago that OLEDs were exotic beasts. Today, they’re available off the shelf with simple interfaces and sample code.

The Tiny Function Generator uses a method called DDS (Direct Digital Synthesis) on an ATtiny85 microcontroller, which [David] wrote up in an earlier post of his about waveform generation on an ATtiny85. With a few extra components like a rotary encoder and OLED display, the Tiny Function Generator fits on a small breadboard. He goes into detail regarding the waveform generation as well as making big text on the small OLED and reading the rotary encoder reliably. His schematic and source code are both available from his site.

Small but functional microcontroller-based electronic equipment are nifty projects, and other examples include the xprotolab and the AVR-based Transistor Tester (which as a project has evolved into a general purpose part identifier.)

These Small PCBs Are Made For Model Rocketry

February 24, 2018 by Donald Papp 18 Comments

Model rocketry hobbyists are familiar with the need to roll their own solutions when putting high-tech features into rockets, and a desire to include a microcontroller in a rocket while still keeping things flexible and modular is what led [concretedog] to design a system using 22 mm diameter stackable PCBs designed to easily fit inside rocket bodies. The system uses a couple of 2 mm threaded rods for robust mounting and provides an ATTiny85 microcontroller, power control, and an optional small prototyping area. Making self-contained modular sleds that fit easily into rocket bodies (or any tube with a roughly one-inch inner diameter) is much easier as a result.

The original goal was to ease the prototyping of microcontroller-driven functions like delayed ignition or altimeter triggers in small Estes rockets, but [concretedog] felt there were probably other uses for the boards as well and made the design files available on GitHub. (Thanks!)

We have seen stackable PCBs for rocketry before with the amazingly polished M3 Avionics project, but [concretedog]’s design is much more accessible to some hobbyist-level tinkering; especially since the ATTiny85 can be programmed using the Arduino IDE and the boards themselves are just an order from OSH Park away.

[via Dangerous Prototypes Blog]

Debugging An Arduino With An Arduino

February 7, 2018 by Tom Nardi 15 Comments

As every Hackaday reader knows, and tells us at every opportunity in the comments, adding an Arduino to your project instantly makes it twice as cool. But what if, in the course of adding an Arduino to your project, you run into a problem and need to debug the code? What if you could use a second Arduino to debug the first? That would bring your project up to two Arduinos, instantly making it four times as awesome as before you started! Who could say no to such exponential gains?

Not [Wayne Holder], that’s for sure. He writes in to let us know about a project he’s been working on for a while that allows you to debug the execution of code on an Arduino with a second Arduino. In fact, the target chip could even be another AVR series microcontroller such as a the ATTiny85. With his software you can single-step through the code, view and modify values in memory, set breakpoints, and even disassemble the code. Not everything is working fully yet, but what he has so far is very impressive.

The trick is exploiting a feature known as “debugWIRE” that’s included in many AVR microcontrollers. Unfortunately documentation on this feature is hard to come by, but with some work [Wayne] has managed to figure out how most of it works and create an Arduino Sketch that lets the user interact with the target chip using a simple menu system over the serial monitor, similar to the Bus Pirate.

[Wayne] goes into plenty of detail on his site and in the video included after the break, showing many of the functions he’s got working so far in his software against an ATTiny85. If you spend a lot of time working on AVR projects, this looks like something you might want to keep installed on an Arduino in your tool bag for the future.

Debugging microcontroller projects can be a huge time saver when your code starts running on real hardware, but often takes some hacking to get working.

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A Game That Does More With Less

February 4, 2018 by Donald Papp 17 Comments

[David Johnson-Davies] created a minimal Secret Maze Game using a single ATTiny85 and a few common components. This simple game uses four buttons, four LEDs, and a small speaker. The player moves in the four cardinal directions using buttons, and the LEDs show walls and corridors. If an LED is lit, it means the path in that direction is blocked by a wall, and attempting to move in that direction will make a beep. When the player reaches the exit, a short victory tune chirps from the speaker.

Sample maze. A 16×16 matrix is allocated for maze designs.

Since the ATTiny85 has only five I/O lines, [David] had to get a bit clever to read four buttons, display output on four LEDs, and drive a little speaker. The solution was to dedicate one pin to the speaker and the other four to charlieplexing, which is a method of driving more LEDs than you have pins. It takes advantage of the fact that most microcontroller pins can easily switch state between output high, output low, or ~~low-impedance~~ high-impedance input.

As for the buttons, [David] charlieplexed them as well. Instead of putting an LED in a charlieplexed “cell”, the cell contains a diode and an SPST switch in series with the diode. To read the state of the switch, one I/O line is first driven low and the other I/O line is made an input with a pullup. A closed switch reads low on the input, and an open switch reads high. With charlieplexing, four pins is sufficient for up to twelve LEDs (or buttons) in any combination, which is more than enough for the Secret Maze.

Charlieplexing is also what’s behind this 110 LED micro-marquee display, or this elegant 7-segment display concept that takes advantage of modern PCB manufacturing options.