Tag Archives: ATtiny 85

Open source camera has Atmel under the hood

Kevin Kadooka has designed an open source camera with Adafruit’s Atmel-based Trinket platform (ATtiny85) under the hood.

Dubbed “Lux,” the 6×6 box camera (120 roll film) was originally prototyped using an Arduino Uno (ATmega328). 

Key project components include include Adafruit’s quarter-size protoboard, transistors (TIP120), diode (1N4001), 5V solenoid, rotary switch (10 position BCD DIP), rocker switch (SPST), resistors, 7.4 battery, connectors (JST PH, JST BEC), and a momentary button (SPST w/LED).

Additional specs? PCX lens, positive meniscus lens, mirror, and an electromechanical single-leaf shutter.

“Until now, all of my camera- building efforts utilized parts repurposed from old, obsolete cameras, and for good reason,” Kadooka explained on the project’s official page. 

”Each constituent part of the modern camera, from the shutter, lens, aperture diaphragm, and film transport, are much too complex and delicate for the average hobbyist to reproduce. Borrowing parts from old cameras is usually the go-to solution for most DIY’ers (myself included), however I don’t think this is a sustainable technique.”

As such, Kadooka’s primary goal is to design and produce a fully-fledged using easily purchased off-the-shelf components – without having to rely on anything pulled from a potentially valuable piece of equipment.

“A secondary goal is also to make this camera completely open source through rapid-prototyping techniques such as laser cutting and 3D printing, and the Arduino physical computing platform,” he added.

Interested in learning more about the open source camera? You can check out Kadooka’s detailed instructions and spec sheets here.

Building a Trinket-based (ATtiny 85) rover

Adafruit’s Trinket platform – based on Atmel’s versatile ATtiny85 microcontroller (MCU) – has been used to power a number of diverse projects in recent months, including an audio player, flickering candle in a jar, a knock drawer lock and a sound-reactive LED color organ.

 Today, we’re going to take a closer look at a Trinket-powered rover designed by Rick Winscot for the Adafruit crew.

“Science, Technology, Engineering, (Art) and Math (STEM / STEAM) curriculum is gaining momentum in K-12 education,” Winscot explained in a recent Adafruit tutorial. “It’s exciting to see so many new makers and engineers learning how fun it is to make! I wanted to design a low cost robot that anyone could build if they have access to a 3D printer.”

Aside from the Atmel-powered Trinket, key project components include 7 plastic parts, a tiny breadboard, one 34xAA battery holder, 2X continuous rotation micro servos, 3X female/male jumpers, 3X M3 10mm screws, 1X M3 hex nut and double-sided foam tape. 

For distance measurement, Makers can use a Parallax Ping))) Sensor, Grove Ultrasonic Ranger, or Maxbotix Ultrasonic Rangefinder.

In addition, Winscot uses chain bracelets for the build, instead of 3D printing tracks/treads.

“I had some success 3D printing ones with flexible filament but the total cost was too high. That’s when I stumbled into these… ‘chain bracelets’ from Oriental Trading. You can buy a dozen for less than ten dollars; which will make six rovers,” he said.

On the source code side, Winscot created a Parallax Ping))) Distance Sensor sketch which he describes as an ultra-bare bones starting point.

Interested in learning more about the Trinket-powered rover? The relevant .stl files are available here, while Winscot’s detailed tutorial can be read here.

Reactive drums with Atmel and Adafruit

The Adafruit crew (Noe and Pedro) has designed a slick reactive drum system based on the Atmel-powered Gemma (ATtiny85) and NeoPixels. Essentially, this means musicians and Makers can easily upgrade their drum kits with sound reactive LEDs.

“This build uses a mic amp sensor and Gemma to light up NeoPixels to the beat of your drums. The cost of this build is considerably lower than other kits. It is also compact, rechargable and mobile,” the duo explained in a recently published Adafruit tutorial. “We made a circuit for a snare, mid-tom, hi-tom and a drum kick. Each drum is independent from one another but can also trigger other pieces if stricken loud enough. [Plus], our project cost one third of the price of other led drum kits on the market.”

To kick off the project, Makers may want to prototype their circuits using small alligator clips to connect the components together.

“The pins on the mic sensor are small, so be sure to double check your connections if you’re having trouble getting the circuit to work. It might be easier to solder wires to the mic and then alligator clip to those,” Noe and Pedro noted. “Since drumsets are so loud, the code is set to have a low sensitivity for the mic, so make sure to give a loud sound when testing the NeoPixels audio response. Rubbing the microphone with your finger is a good way to get a reaction.”

More specifically, the NeoPixel strips digital input connects to pin D0 of the Gemma, with the negative connection of the NeoPixel strip going to the ground pin on the Gemma. Meanwhile, the positive power wire of the NeoPixel LED strip connects to the VBat pin of the Gemma (not 3.3V). The out pin on the mic amp goes to pin A1/D2 of the Gemma (an analog input pin), with the positive power breakout pin on the mic amp connecting to the 3.3v pin of the Gemma and the negative ground pin of the mic amp sharing the same ground connection on the Gemma (together with the NeoPixel strip).

Once Makers have the circuit prototype tested and working, they can continue the project by soldering wires to the above-mentioned components for a solid connection.

“Start by measuring lengths of wires needed for connecting the Gemma to the NeoPixels and mic sensor. The wires should be long enough to run through the air hole and inside the drum shell,” the Adafruit crew added.

“The main circuit (which contains the Gemma, battery and switch) will be fitted inside an enclosure and mounted on the side of the drum shell closest to the air hole. To see if your wires are long enough, place the Gemma into position and see if the wire is long enough to connect the NeoPixel strips inside the drum shell. It’s fine to have some extra wire.”

Interested in learning more about building a reactive drum system using the Atmel-powered Gemma and Neopixels? You can check out Adafruit’s full tutorial here.

Adafruit monitors temp and humidity with Atmel MCU

Adafruit’s Mike Barela has designed a temperature and humidity monitor built around the Atmel-powered (ATtiny85) Trinket. As Barela notes, monitoring sensors are a very common feature in current-gen Internet of Things (IoT) projects.

“While the Trinket does not have a serial monitor built in, it [does] talk over various protocols including software serial, I2C (two wire) and SPI,” Barela explained. “This project can be placed in a very small enclosure and used anywhere environmental monitoring is needed. [Plus], the code and concepts may be used in a number of your own projects.”

Aside from the Atmel-powered Trinket, key components include:

  • RGB backlight negative/positive LCD 16×2 + extras
  • Standard LCD 16×2 + extras
  • i2c / SPI character LCD backpack
  • DHT22 temperature-humidity sensor + extras/DHT11 basic temperature-humidity sensor
  • Breadboarding wire bundle
  • Half-size breadboard

In terms of software libraries, Barela’s project uses TinyWireM (a Trinket-compatible alternative to the Arduino Wire), TinyLiquidCrystal and TinyDHT. Meanwhile, Adafruit’s I2C / SPI character LCD backpack allows Makers to easily control the display by sending data over the two wire I2C interface.

“Standard LCDs require a large number of digital pins, [so] use of the I2C backpack reduces the pins needed considerably,” said Barela. “This project features a 16×2 display, displaying temperature and humidity without using a great deal of memory, which is important on a small microcontroller like the Trinket.”

According to Barela, the I2C backpack may be assembled and placed on the back of the display.

“The color displays have a couple of extra connectors – pins 16, 17, and 18 control the three color backlights. If you connect pin 16, the I2C will control the red light,” he continued. “You can choose to put a jumper from one of the backlight pins to backpack pin 16 to choose a different color or connect the pins high to keep them on all the time. Making the pin choice before soldering on the backpack allows you the most flexibility in choosing your backlight color, or you can just go with a ‘classic’ blue & white 16×2 LCD.”

Interested in learning more about Adafruit’s temperature and humidity monitor built around the Atmel-powered Trinket? You can check out Mike Barela’s detailed tutorial here.