computer science

Sun SPOT

Sun SPOT is a computer science topic covered in the lgStudy science library. This page brings together a partial reference excerpt, illustrations, worked examples, real-world applications and a short study plan, so you can understand Sun SPOT rather than just read about it. In short: Sun SPOT (Sun Small Programmable Object Technology) was a sensor node for a wireless sensor network developed by Sun Microsystems announced in 2007. The device used the IEEE 802.15.4 standard for its networking, and unlike other available sensor nodes, used the Squawk Java virtual machine.

Key takeaways

Sun SPOT belongs to computer science; place it in that map before memorising details.
Learn the definition first, then one example that makes the definition concrete.
Connect Sun SPOT to a quantity you can measure, compute or draw — that is where exam questions come from.
Reproduce the core statement of Sun SPOT from memory before moving on to harder problems.

Reference excerpt

Sun SPOT (Sun Small Programmable Object Technology) was a sensor node for a wireless sensor network developed by Sun Microsystems announced in 2007. The device used the IEEE 802.15.4 standard for its networking, and unlike other available sensor nodes, used the Squawk Java virtual machine. After the acquisition of Sun Microsystems by Oracle Corporation, the SunSPOT platform was supported but its forum was shut down in 2012. A mirror of the old site is maintained for posterity.

Hardware The completely assembled device fit in the palm of a hand. Its first processor board included an ARM architecture 32 bit CPU with ARM920T core running at 180 MHz. It had 512 KB RAM and 4 MB flash memory. A 2.4 GHz IEEE 802.15.4 radio had an integrated antenna and a USB interface was included. A sensor board included a three-axis accelerometer (with 2G and 6G range settings), temperature sensor, light sensor, 8 tri-color LEDs, analog and digital inputs, two momentary switches, and 4 high current output pins. The unit used a 3.7V rechargeable 750 mAh lithium-ion battery, had a 30 uA deep sleep mode, and battery management provided by software.

Software The device's use of Java device drivers is unusual since Java is generally hardware-independent. Sun SPOT uses a small Java ME Squawk which ran directly on the processor without an operating system. Both the Squawk VM and the Sun SPOT code are open source. Standard Java development environments such as NetBeans can be used to create SunSPOT applications. The management and deployment of application are handled by ant scripts, which can be called from a development environment, command line, or the tool provided with the SPOT SDK, "solarium". The nodes communicate using the IEEE 802.15.4 standard including the base-station approach to sensor networking. Protocols such as Zigbee can be built on 802.15.4. Sun Labs reported implementations of RSA and elliptic curve cryptography (ECC) optimized for small embedded devices.

Availability Sun Microsystems Laboratories started research on sensor networks around 2004. After some initial experience using "Motes" from Crossbow Technology, a project began under Roger Meike to design an integrated hardware and software system. Sun sponsored a project at the Art Center College of Design called Autonomous Light Air Vessels in 2005. The first limited-production run of Sun SPOT development kits were released April 2, 2007, after months of delays. This introduction kit included two Sun SPOT demo sensor boards, a Sun SPOT base station, the software development tools, and a USB cable. The software was compatible with Windows XP, Mac OS X 10.4, and common Linux distributions. Some demonstration code was provided. A developer from Sun gave a demonstration in September 2007. After investigating commercial use, Sun moved to focus on educational users. The entire project, hardware, operating environment, Java virtual machine, drivers and applications, was available as open source in January 2008. Oracle Corporation acquired Sun Microsystems in 2010 and continued Sun SPOT development, through release 8 of the hardware (with Sun-Oracle logo) by March 2011. The 2011 version included larger memories and a faster processor, but with fewer inputs. In 2012 the forum said it would be "down for maintenance" until "mid-June". A new forum was started on the Oracle Technology Network on May 7, 2013. David G. Simmons, one of the SunSPOT developers for Sun Microsystems, maintained a blog through the end of 2010. He opened an alternative developers forum in July 2013 not connected to Oracle. When the project was shut down, the lead hardware engineer for the SunSPOT project, Bob Alkire, archived the hardware design on his personal website.

References

External links Official website

Illustrations

Worked examples

Example 1 — a first encounter with Sun SPOT

Start with the simplest possible case. Write down what Sun SPOT claims or describes in one sentence, then invent the smallest concrete situation in which that sentence is true. In computer science, the smallest case is usually a single object, a single equation or a single measurement. Check that every symbol or term in your sentence has a meaning in that case.

Example 2 — changing one variable

Take the situation from Example 1 and change exactly one quantity: double it, halve it, or set it to zero. Predict what should happen to Sun SPOT before you calculate. Comparing your prediction with the result is the fastest way to find out whether you understand the idea or only the words.

Example 3 — an exam-style question

Typical questions about Sun SPOT ask you to (a) state it precisely, (b) apply it to given data, and (c) explain a limitation. Practise writing all three answers in under five minutes; the third part is what separates a full-mark answer from an average one.

Applications of Sun SPOT

In research: Sun SPOT appears in computer science research whenever the underlying quantities have to be modelled precisely. Papers usually cite it as a starting assumption and then explore where it breaks down.
In technology and industry: Engineering practice reuses Sun SPOT in design rules, simulations and safety margins. Knowing the idea lets you read a specification sheet and understand why the numbers look the way they do.
In the classroom: Sun SPOT is common in secondary-school and first-year university syllabi. It links to neighbouring topics Computer-related introductions in 2007, Sensors, Smart materials, so understanding it makes those chapters shorter.
In everyday life: Look for Sun SPOT outside the textbook — in sport, cooking, traffic, electronics or the sky above you. An example you found yourself is remembered far longer than one you were given.

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How to study Sun SPOT in 20 minutes

Read the reference excerpt below once, without taking notes.
Close the page and write down what Sun SPOT means in your own words.
Compare your version with the excerpt and mark what you missed.
Work through the three examples above with pen and paper.
Explain Sun SPOT out loud to somebody else — or to Teacher Smith in the lgStudy chat.

Frequently asked questions

What is Sun SPOT in simple terms?

Why does Sun SPOT matter?

Because it connects several computer science ideas at once: it gives you a definition you can apply, a quantity you can calculate, and a way to check whether a result is plausible.

How should I study Sun SPOT?

Read the excerpt, restate it from memory, then work through the examples and applications listed on this page. The five-step study plan above takes about twenty minutes.

What does this page cover?

It gives you a compact reference excerpt plus original lgStudy explanations, examples, applications and study material on Sun SPOT.