The Remoteduino Nano Is A Tiny IR Remote That’s Truly Universal

June 18, 2023 by Robin Kearey 13 Comments

Universal remotes are extremely convenient if they work correctly. But setting them up can be quite a hassle: often, you need to browse through long lists of TV models, key in the codes on the remote with just a blinking LED as confirmation, and then pray that the manufacturer included the correct codes for all your equipment. IR isn’t a very complicated technology, however, so it’s perfectly possible to roll your own universal remote, as [sjm4306] shows in his latest project, the Remoteduino Nano. It’s a fully programmable IR remote that gives you maximum flexibility when emulating the codes for those obscure A/V systems scattered around your home.

The remote runs on an ATmega328p in a tiny QFN package, which drives a standard 5 mm IR LED through a transistor. Eight buttons are available to the user, which can be freely mapped to any desired code. A five-pin header is included to program the ATmega through its serial port. However, this was mainly done to help debug – a user who only needs to program the device once would typically use a pogo-pin-based adapter instead.

Currently, codes can only be programmed through the serial port, but there’s also an IR receiver present that can be used to copy codes from an existing remote. [sjm4306] hasn’t implemented this feature in software yet, but will probably do so in a future update of the project’s Arduino sketch. If you’re impatient, you can also have a go at it yourself since all code and the board’s Gerber files are freely available for download.

Its tiny size makes the Remoteduino Nano a convenient tool to keep in your drawer if you like to tinker with A/V systems and keep losing those remotes. The Nano is actually an improved version of the original Remoteduino project that [sjm4306] developed a couple of years ago. The problem of a truly universal remote is one that dates back several decades, however.

Continue reading “The Remoteduino Nano Is A Tiny IR Remote That’s Truly Universal” →

Kitchen timer project in a angled green 3d printed case with a 7 segment display and knob.

Printing A Brutalist Kitchen Timer

April 2, 2023 by Abe Connelly 23 Comments

A kitchen timer is one of those projects that’s well defined enough to have a clear goal, but allows plenty of room for experimentation with functionality and aesthetics. [Hggh]’s exploration of the idea is a clean, Brutalist kitchen timer.

The case for [Hggh]’s kitchen timer is 3D printed with openings for a TM1637 four digit, seven segment display and for a KY-040 rotary encoder with knob attached. The internals are driven by an ATmega328P powered from a 18650 cell with a DW01-P battery protection chip and a TP4056 chip for charging. On the back of the case is a power switch and USB-C connector for power. It looks like the 3D printed case was sanded down to give it a smooth matte surface finish.

All the project files, including the STLs, OpenSCAD code, and KiCAD design, are available on GitHub. This Brutalist kitchen timer project is a nice addition to some of the kitchen timers we’ve featured in the past, including a minimalist LED matrix timer and a Nixie timer with keypad.

A pair of PCBs with OLED character displays, showing a simple encryption program

The CryptMaster 2001 Provides Basic Lessons In Cryptography

February 13, 2023 by Robin Kearey 6 Comments

Sending secret messages to your friends is fun, but today it’s so simple that you don’t even notice it anymore: practically any serious messaging system features encryption of some sort. To teach his kids about cryptography, [Michal Zalewski] therefore decided to bring the topic to life by building a handheld encryption system, called the CryptMaster 2001.

The system consists of an identical pair of hand-held devices built on prototype PCBs. A standard 16×2 character OLED display is used as an output device, which generates the ciphertext in real time as the plaintext is entered character by character through a rotary encoder. An ATmega328P manages the input and output routines and performs the encryption.

For ease of use, [Michal] wanted to use a reciprocal cipher, meaning one that uses the same operation for encryption and decryption. Trivial ciphers like ROT13 would be a bit too easy to crack, so he devised a slightly more complex system where each character in the input is encoded using a separate rearranged alphabet – a basic polyalphabetic substitution cipher.

[Michal]’s kids apparently had some good fun with the CryptMaster 2001, until his eldest son managed to reverse-engineer the encryption method, enabling him to decode messages without having access to one of the devices. This made the project a pretty decent lesson about the limits of basic cryptography: simply swapping letters doesn’t present a real challenge to anyone. Luckily, much more secure methods are available, even if you’re only using pen and paper.

3d printed tiny gym in a box with mirror and led strip lighting

Get Pumped For This Miniature Gym

January 9, 2023 by Abe Connelly 5 Comments

[Duncan McIntyre] lives in the UK but participated in a secret Santa gift exchange for his Dutch friends’ Sinterklaas celebration. In traditional maker fashion, [Duncan] went overboard and created a miniature gym gift box, complete with flashing lights, music and a motorized lid.

[Duncan] used [TanyaAkinora]’s 3D printed tiny gym to outfit the box with tiny equipment, with a tiny mirror added to round out the tiny room. An ATmega328P was used as the main microcontroller to drive the MP3 player module and A4988 stepper motor controller. The stepper motor was attached to a drawer slide via a GT2 timing belt and pulley to actuate the lid. Power is provided through an 18V, 2A power supply with an LM7805 providing power to the ATmega328P and supporting logical elements. As an extra flourish, [Duncan] added some hardware audio signal peak detection, fed from the speaker output, which was then sampled by the ATmega328P to be able to flash the lights in time with the playing music. A micro switch detects when the front miniature door is opened to begin the sequence of lights, song and lid opening.

[Duncan] provides source on GitHub for those curious about the Arduino code and schematics. We’re fans of miniature pieces of ephemera and we’ve featured projects ranging from tiny 3D printed tiny escalators to tiny arcade cabinets.

Video after the break!

Continue reading “Get Pumped For This Miniature Gym” →

Two hands holding a 3d printed alarm clock with an LCD display, snooze button and knob on top

IO Connected Radio Alarm Clock

December 19, 2022 by Abe Connelly 3 Comments

[CoreWeaver] creates an alarm clock that includes features one might expect in such a project, including an FM radio, snooze button inputs and a display, but goes beyond the basic functionality to include temperature sensing and a PC connection, opening the way for customizable functionality.

An Atmega328 is used for the main microcontroller which communicates via I2C both to a DS1307 real time clock (RTC) and a TEA5767 FM module. The main power comes from a 9V power source with an LM317 and LM7805 linear regulators providing a 3.3V and 5V power rail, respectively. Most of the electronics are powered using 5V except for the TEA5767, which is powered from the 3.3V rail and has its I2C communication levels shifted from 5V to 3.3V. The audio output of the TEA5767 feeds directly into the TDA7052 audio amplifier to drive the speakers. Since the RTC has an auxiliary coin cell battery for power, the alarm clock can keep accurate time even when not plugged in. Continue reading “IO Connected Radio Alarm Clock” →

Minimal Tic Tac Toe Business Card

September 24, 2022 by Stephen Ogier 38 Comments

The PCB business card has long been a way for the aspiring electronics engineer to set themself apart from their peers. Handing out a card that is also a two player game is a great way to secure a couple minutes of a recruiter’s time, so [Ryan Chan] designed a business card that, in addition to his contact information, also has a complete Tic-Tac-Toe game built in.

[Ryan] decided that an OLED display was too expensive for something to hand out and an LED matrix too thick, so he decided to keep it simple and use an array of 18 LEDs—9 in each of two colors laid out in a familiar 3×3 grid. An ATmega328p running the Arduino bootloader serves as the brains of the operation. To achieve a truly minimal design [Ryan] uses a single SMD pushbutton for control: a short press moves your selection, a longer press finalizes your move, and a several-second press switches the game to a single-player mode, complete with AI.

If you’d like to design a Tic-Tac-Toe business card for yourself, [Ryan] was kind enough to upload the schematics and code for his card. If you’re still pondering what kind of PCB business card best represents you, it’s worth checking out cards with an updatable ePaper display or a tiny Tetris game.

Continue reading “Minimal Tic Tac Toe Business Card” →

The Inner Machinations Of The Arduino Are An Enigma

September 19, 2022 by Bryan Cockfield 88 Comments

Arduinos have been the microcontroller platform of choice for nearly two decades now, essentially abstracting away a lot of the setup and lower-level functions of small microcontrollers in favor of sensible IDEs and ease-of-use. This has opened up affordable microcontrollers to people who might not be willing to spend hours or days buried in datasheets, but it has also obscured some of those useful lower-level functions. But if you want to dig into them, they’re still working underneath everything as [Jim] shows us in this last of a series of posts about interrupts.

For this how-to, [Jim] is decoding linear timecodes (LTCs) at various speeds. This data is usually transmitted as audio, so the response from the microcontroller needs to be quick. To make sure the data is decoded properly, the first thing to set up is edge detection on the incoming signal. Since this is about using interrupts specifically, a single pin on the Arduino is dedicated to triggering an interrupt on these edges. The rest of the project involves setting up an interrupt service routine, detecting the clock signal, and then doing all of the processing necessary to display the received LTC on a small screen.

The project page goes into great detail about all of this, including all of the math that needs to be done to get it set up correctly. As far as general use of interrupts goes, it’s an excellent primer for using the lower-level functionality of these microcontrollers. And, if you’d like to see the other two projects preceding this one they can be found on the first feature about precision and accuracy, and the second feature about bitbanging the protocol itself.