attiny85 tutorials

Introduction to ATtiny85: Basics and Features

Understanding the ATtiny85

The ATtiny85 is a remarkable piece of technology that embodies the marvels of modern microcontrollers. Part of Atmel’s (now Microchip) tinyAVR series, it is a compact, low-power microcontroller that has gained popularity among hobbyists, educators, and professionals for its versatility and simplicity. Despite its small size, the ATtiny85 packs a powerful punch, making it an ideal choice for a wide range of applications, from simple DIY projects to complex industrial systems.

Physical Characteristics

The ATtiny85 stands out for its remarkably compact size. Typically available in an 8-pin Dual In-line Package (DIP) or an 8-pin Small Outline Integrated Circuit (SOIC), it is designed for minimalism and efficiency. The DIP version, with its through-hole design, is particularly popular among hobbyists and educators for its ease of use on breadboards and prototyping boards. The SOIC version, on the other hand, is more suited to surface-mounted applications, which is a common requirement in professional and commercial product design.

Pin Configuration

The ATtiny85’s 8 pins serve multiple purposes, a design choice that exemplifies its versatility:

VCC and GND Pins: These are the power supply pins. VCC is the positive supply voltage, which typically ranges between 2.7V and 5.5V, and GND is the ground.

Reset Pin: This pin is used to reset the microcontroller’s program, starting it over from the beginning. It can also be configured as an additional I/O pin if the reset functionality is not required.

I/O Pins: The ATtiny85 has six I/O (Input/Output) pins, which are multipurpose. These pins are capable of digital input and output and can also serve functions like analog input (ADC), PWM output, and interfacing with various peripherals.

Analog-to-Digital Converter (ADC) Inputs: Among the I/O pins, some can be used as ADC inputs. This feature allows the ATtiny85 to interface with analog sensors and devices, converting their analog signals into digital values.

PWM Output: Certain I/O pins also support PWM (Pulse Width Modulation). This is particularly useful for controlling devices like motors and LEDs, where varying levels of power are needed.

Physical Connectivity

The physical connectivity of the ATtiny85 is straightforward, catering to its role as a user-friendly microcontroller. The DIP version’s pins can be easily inserted into a breadboard or soldered onto a PCB. For more permanent applications, especially in space-constrained environments, the SOIC version can be soldered directly onto a surface-mount PCB.

Heat Dissipation

Given its low power consumption, the ATtiny85 typically does not require any special considerations for heat dissipation under normal operating conditions. This makes it even more suitable for small-scale projects where space and simplicity are crucial.

Durability and Lifespan

The ATtiny85 is built to be robust within its operating specifications. Its solid-state construction ensures a long lifespan, particularly when operated within its recommended voltage and temperature ranges. As with all electronic components, adherence to these operational guidelines is key to ensuring the longevity of the device.

The physical characteristics of the ATtiny85 contribute significantly to its appeal and usability. Its small size, versatile pin configuration, and ease of integration make it an ideal choice for a wide array of applications, from simple hobbyist projects to sophisticated commercial products. Whether you’re building a prototype on a breadboard or designing a compact, integrated circuit, the ATtiny85 offers a practical and efficient solution.

Programming the ATtiny85

Programming the ATtiny85 is a unique experience compared to other microcontrollers due to its minimalistic design and limited resources. This section delves into the various aspects of programming the ATtiny85, including the tools, languages, and techniques used.

Tools for Programming

ISP (In-System Programmer): To program the ATtiny85, an ISP is essential. This device communicates with the ATtiny85 using SPI (Serial Peripheral Interface) to upload code. Common ISPs include USBtinyISP, AVRISP mkII, and even Arduino boards configured as an ISP.

Arduino as ISP: A popular method among hobbyists is using an Arduino board as an ISP. This involves connecting the ATtiny85 to an Arduino and using the Arduino IDE to upload the code. This method is cost-effective and accessible for those already familiar with Arduino.

Dedicated Hardware Programmers: For a more permanent or professional setup, dedicated hardware programmers like USBtinyISP provide a reliable way to program the ATtiny85.

Software and IDEs

Arduino IDE: The Arduino IDE is widely used for programming the ATtiny85 due to its simplicity and the extensive community support. By adding ATtiny85 support to the Arduino IDE through board manager or external cores, programmers can write code in a familiar environment and upload it directly to the ATtiny85.

AVR-GCC and AVRDUDE: For those preferring a more traditional approach, the combination of AVR-GCC (a compiler for AVR microcontrollers) and AVRDUDE (a utility for downloading/uploading/manipulating firmware of AVR microcontrollers) is a powerful toolchain. This setup is more complex but offers greater control and efficiency in programming.

Programming Language

The primary language used for programming the ATtiny85 is C/C++, especially when using the Arduino IDE or AVR-GCC. The language provides a good balance between high-level functionality and low-level hardware access, making it ideal for the resource-constrained environment of the ATtiny85.

Writing Efficient Code

Given the limited memory and processing power of the ATtiny85, writing efficient code is crucial. This involves optimizing both the size and speed of the code. Techniques such as using direct port manipulation for I/O, minimizing the use of floating-point operations, and optimizing loops and conditional statements are important.

Libraries and Code Reuse

There are numerous libraries available for the ATtiny85, especially when using the Arduino IDE. These libraries provide pre-written code for a wide range of functionalities, from sensor interfacing to complex algorithms. However, due to memory constraints, care must be taken to use or modify libraries that are specifically optimized for the ATtiny85.

Debugging and Troubleshooting

Debugging on the ATtiny85 can be challenging due to the lack of advanced debugging features like those found in more sophisticated microcontrollers. Common practices include using LED indicators, serial output (with additional hardware), and logical debugging through code analysis.

Uploading Code

The process of uploading code to the ATtiny85 involves connecting it to the ISP, selecting the appropriate board and port in the IDE or programming software, and initiating the upload process. It is crucial to ensure correct connections and configurations to avoid errors.

Programming the ATtiny85 is a rewarding challenge that hones a programmer’s ability to write efficient and concise code. Whether using the Arduino ecosystem for ease and accessibility or delving into more traditional AVR programming methods for greater control, the ATtiny85 serves as an excellent platform for developing skills in embedded systems programming. The key to success lies in understanding the limitations and capabilities of the ATtiny85 and leveraging the available tools and resources to their fullest potential.

Applications of ATtiny85

The ATtiny85 microcontroller, despite its small size, offers a vast array of practical and innovative applications. Its versatility and simplicity make it an ideal choice for various projects, ranging from basic electronic tasks to more complex and creative applications. Here, we explore some of the popular and inventive uses of the ATtiny85.

  1. Wearable Electronics

The compact size of the ATtiny85 makes it perfect for wearable technology. It can be used to power smart watches, fitness trackers, or interactive clothing. These wearables can monitor health metrics, change color, or even react to environmental factors, thanks to the ATtiny85’s ability to interface with sensors and LEDs.

  1. Home Automation

In the realm of smart homes, the ATtiny85 can control lighting, temperature, or even small appliances. Its low power consumption makes it ideal for battery-operated devices like remote controls, automatic curtain openers, or temperature sensors.

  1. Hobbyist Projects and Prototyping

For hobbyists and makers, the ATtiny85 is a go-to for DIY electronics projects. It’s used in constructing custom gadgets, simple games, electronic dice, small robots, or interactive art installations. The ATtiny85 is particularly loved in the maker community for its ease of use and flexibility.

  1. Educational Tools and Kits

In educational settings, the ATtiny85 serves as a great learning tool. It can be used in teaching the basics of electronics and programming. Its simplicity allows students to quickly grasp fundamental concepts without being overwhelmed by complexity.

  1. Consumer Electronics

In commercial products, the ATtiny85 finds applications in consumer electronics like toys, small household gadgets, or interactive promotional items. Its cost-effectiveness and ease of integration make it suitable for mass-produced items.

  1. Battery-Powered Devices

The ATtiny85’s low power consumption is ideal for battery-powered devices. This includes portable weather stations, handheld games, or custom remote controllers.

  1. Industrial Control Systems

Though not as powerful as some industrial microcontrollers, the ATtiny85 is still useful for simple control systems in an industrial setting, like managing small automation tasks or as part of a larger control system.

  1. Robotics

In robotics, especially in miniature or hobbyist models, the ATtiny85 can control motors, read sensor inputs, and manage navigation systems.

  1. Personalized Gadgets

For custom-built gadgets like personalized clocks, weather stations, or novelty items, the ATtiny85 offers a compact and efficient solution.

  1. Event-Driven Automation

The ATtiny85 is suitable for applications where actions are triggered by specific events, like a light turning on when a door opens.

  1. Light and Display Control

From controlling LED arrays to managing small LCD displays, the ATtiny85 is effective in managing visual outputs in devices.

The ATtiny85’s small footprint, combined with its versatility, makes it an attractive choice for a multitude of applications across various fields. From simple DIY projects to more sophisticated commercial products, the ATtiny85 provides an excellent platform for both learning and developing innovative solutions. Its adaptability and ease of use continue to endear it to a wide range of users, from hobbyists and educators to professionals and artists.

Advantages and Limitations

The primary advantage of the ATtiny85 is its size. It is ideal for projects where space is at a premium. Its simplicity also makes it a great learning tool for those new to electronics and programming. However, its limited I/O pins and memory can be restrictive for more complex applications.


The ATtiny85 is a testament to the adage that great things come in small packages. Its combination of size, power, and flexibility makes it a go-to choice for a multitude of projects. Whether you are a hobbyist looking to experiment, an educator teaching the basics of electronics, or a professional developing a compact product, the ATtiny85 offers a reliable and efficient platform to bring ideas to life.

This overview of the ATtiny85 highlights its capabilities and potential applications. Its simplicity, coupled with its robust feature set, makes it an invaluable tool in the world of microcontrollers. For anyone looking to delve into the realm of electronics, the ATtiny85 is an excellent starting point, offering a perfect balance between functionality and accessibility.

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