Tag Archives: shield

OpenSprinklerBee has Atmel under the hood

The OpenSprinklerBee (OSBee) is an open-source Atmel-based sprinkler timer (prototype) designed to work with battery-operated valves.

Recently debuted by RaysHobby, the platform is powered by an ATmega328 microcontroller (MCU) paired with a nRF24L01 2.4G RF transceiver.

Additional key components include two AA batteries (boosted to 3.3V), SMT buzzer, push-button, 16KB EEPROM, PWM-driven boost converter, H-bridge (to drive sprinkler solenoid), soil moisture sensor and a Serpac 121 enclosure with water-proof perimeter seal.

“The name ‘Bee’ comes from the abbreviation Battery-Enabled Extension. It’s coincidence that it sounded more like XBee. It may very well have an XBee slot in the end, but the name was not intended to imply XBee,” Ray of RaysHobby.net explained in a blog post.

“Also, ‘Bee’ reminds me of the garden, and gardens need to be watered, so, there is the connection. Different from the classic OpenSprinkler, OSBee now comes with a water-proof enclosure, which means it can be left outdoors, such as in a garden, and will do its work diligently, like a Bee.”

Although the OSBee itself is still in the prototype stage, Ray recently debut the OSBee Arduino Shield (V 1.0), which is currently available for purchase.

So, how does the OpenSprinkler Bee (OSBee) differ from other OpenSprinkler products?

“The main difference is that OSBee is designed to work with battery-operated sprinkler Tvalves. These valves internally use a latching solenoid, which only draws power when you open or close the valve, and does not draw power if it remains in the same state. So it’s very efficient and suitable for battery-operated controllers,” said Ray.

“The other OpenSprinkler products, such as OpenSprinkler 2.1s, DIY 2.1u, OSPi 1.4, OSBo 1.0, are all designed for 24V AC sprinkler valves, which operate on 24V AC and require a power adapter / transformer.”

While the OSBee shield itself is not equipped with built-in wireless modules, Makers and devs can stack it with other Arduino shields, such as RF, WiFi, Ethernet shields, to provide web connectivity. Indeed, the OSBee Arduino library offers at least one example of using the Arduino Ethernet shield with OSBee shield to create a web interface for sprinkler control.

Interested in learning more? You can check out OSBee here and the OSBee Arduino shield here.

Arduino and RAMPS drive this quilting machine

A Maker by the name of Yu-Ning Lin has designed an Arduino-powered quilting platform that combines the mechanics of a sewing machine with CNC technology.

“The [machine] translates a vector file into G-code and subsequently into Arduino language which then moves the machine,” Yu-Ning explained in a recent Instructables post.

“[It] uses four stepper motors to control the x-axis, y-axis, the bobbin case and the threading. The bed moves in x and y direction, while the threading moves up and down.”

Key project components include:

  • An Atmel-based Arduino Mega 2560 (ATmega2560 MCU)
Ultimaker RAMPS 1.4 (shield)
  • Pololu stepper motor (4)
  • Heat sink (4)
  • SparkFun theragrip thermal tape
Linear motion shaft (2)
  • Linear bearing for 3D printer (4)

According to Yu-Ning, most of the parts were laser-cut, with various pieces first modeled in Rhino.

“Instead of fabricating all mechanical parts of the sewing machine, I took the existing parts of a mini sewing machine and reassembled them for my Arduino Quilting Machine,” Yu-Ning added.

“The only custom parts are the shuttle hook cover, shuttle race, bobbin case and the entire needle bar.”

Interested in learning more? You can check out the project’s official Instructables page here.

Video: Schematic 101 with Atmel’s Paul Rako

In this episode of Atmel Edge, Analog Aficionado Paul Rako discusses the importance of understanding ground symbols for electronic schematics. As Rako notes, Earth ground, chassis ground, power supply return and shield are all different. This video explains why.

“Earth ground has a very precise meaning and a very precise name, and it’s earth ground. My professor, James T. McLaughlin, at Kettering University previously General Motors Institute, pointed out [that] earth ground is a ten foot copper-clad steel rod,” says Rako.

“And you hammer it into the dirt. And you make sure there’s moisture so it has conductivity. The minute you hook a wire to it, well now you got some inductance. And 12-gauge wire all the way to get to where earth ground has to get, which is this third pin on your wall socket, well now it’s got a little resistance, as well.”

Rako also points out that a car isn’t grounded.

“What you want to use is this symbol, which is chassis common. And chassis common, it’s not just cars, but television, radios, PCs with metal things. Anywhere there’s a metal case or a metal mounting point, that’s chassis common. In America, if a human being can touch that metal, you have to connect earth ground at chassis common,” he notes.

“Underwriter’s Laboratory requires a ring terminal so it doesn’t get pulled off. And that way, if there’s a short of high voltage on to the chassis — a wire or something falls down — then it can seek a ground through this earth ground and trip a circuit breaker instead of electrocuting your customers.”

As Rako emphasizes, semiconductor companies who make chips should be using this symbol, the triangle.

“That is power supply return. You may connect your circuit board in the corners, it may connect to chassis, and maybe you want that,” he adds.

“Maybe you want it to connect at 100 places to get a really good RF connection between the circuit board and the metal chassis. But this symbol would be improper on a circuit board, and certainly earth ground is wrong.”

You can watch the video above for more information about schematics. Readers may also want to check out Rako’s previous Debug 101 episode here.

Arduino talks, Android listens

How does an Arduino board “talk” to an Android device without OS instructional code? With the Bluetooth-based (2.1 module WT11i by Bluegiga) Annikken Andee – which can be mounted on an Arduino Uno (Atmel ATmega328), Mega (ATmega1280) or Leonardo (ATmega32u4).

“With the free Annikken Andee Library and Android app, you can create your very own monitor and control UI on Android devices from the Arduino IDE,” the Anniken Andee crew wrote in a recent IndieGoGo post. “This means you are NOT required to develop any Android apps at all.”

So how does it work? Well, the shield communicates with Arduino via the ICSP header (SPI) and pin 8.

On the software side, you simply download the Annikken Andee library for Arduino, unpack the content and copy the ‘Andee’ folder into Arduino IDE library folder. This library contains all the necessary functions to create the user interface on your Android device.

You then download and install the Annikken Andee Android Application from the Google Play Store. Connect your phone to your Arduino via the installed app and voila – you now have a smartphone UI for Arduino.

Additional information about the Annikken Andee is available here on IndieGoGo.