ZigBee Wireless Meshed Networks and the Handy Cricket
Hi folks a couple things going on this week for me:
1) I'm on vacation with the family in Fairfield Glade, TN (The last summer HuRah before the kids go back to school on August 7th).
2) Making final preparations for my 2 workshops at the Midwest Robolab Annual Conference scheduled for August 6-8th held at the Old Mission Hotel. Sponsored and ran by Wichita State University, Kansas.
3) I'm playing around with a wireless mesh networks via ZigBee. It uses the IEEE 802,15.4 Wireless communication standard as it core protocol infrastructure. The concept of wireless mesh networking is to have 1 Coordinator and several Routers that send wireless data via RF signals to each other. To expand the range of the RF signals, additional routers can be added to the network. The coordinator will manage the routers communications to assure correct transmission/reception protocol is being used. The opportunity with Handy Cricket (or LEGO Mindstorms RCX or NXT controller platforms) is to use the ZigBee Router as a front end wireless controller that can interface with these computational-controller devices input ports. The embedded software ( Cricket Logo, Logo Blocks, RCX code, or Robolab) will process the hardwired voltages produced by the router and allow the target computational controller to drive a small electric motor , relay, or other electromechanical devices. Right know, I determining the I/O (Input/Output) of the demo kit using an ohmmeter and voltmeter. I'll be posted additional info on this great Emerging Technology tool for wireless communication in future blogs.
The Midwest Robolab Conference
In the past, I've setup various engineering education workshops for K-12 and adults on technology and how it works. The weekend enrichment programs were strictly hands-on thereby maximizing the learning experience for the student. Now, I'm pleased to announce my two Undergraduate workshops for teachers and university educators using Robolab. Robolab was invented by a Mechanical Engineering Professor at Tufts University named Chris Rogers. Wichita State University is the sponsor of the annual Midwest Robolab Conference being held August 6-8th. I'll be presenting a workshops on enhancing Robolab through Personal Fabrication - teaching Product Development techniques to Non-Engineering students. From the website, here are the goals of the conference.
This workshop will truly be a meeting of the minds and I'll get to meet Chris Rogers as well!!!
The Creation of a Smart Sensor
The Handy Cricket is a great development tool for creating Smart Sensors. Basically, any analog sensor can be embedded with intelligence simply by adding a microcontroller (uC) interface layer. With programming code embedded inside of the uC, the sensor's electrical behavior can be enhanced, thereby allowing greater flexibility to the sensory device. The Handy Cricket provides the necessary intelligence to an ordinary sensor with the aid of Cricket Logo or Logo Blocks programming language. To illustrate this concept a basic op-amp is configured as a comparator circuit/HI Temperature Sensor with a Thermistor and a series 5.6K resistor attached to pin 3(Non-Inverting input). The "2" 10K resistors in series attached to pin 2 (Inverting input) provide a 2.5V reference (Vref) for the comparator circuit. When the thermistor detects a "HI" temperature (Vin voltage > 2.5Vref), the output at pin 1 swings closed to the +5V supply rail wired to pin 8 of the op-amp. The Handy Cricket will process this +5V signal and based on the Cricket Logo or Logo Blocks code embedded within the PIC16C715 uC can provide an appropriate output response. The attached 4 Digit Seven Segment Display is used to read the maximum value (Analog to Digital[AD] Count Value) input voltage being applied at pin 3. For example, if pin 3 voltage is +5V, the maximum AD count value will be 255. With the Handy Cricket used as the core programming platform, the possibilities of Smart Sensor creation are endless. Enjoy!!!
Electronic Resources for Handy Cricket Sci-Tech and Robo Gadget Enthusiast
In teaching electronics a resource of tips and tools makes the theory more practical and easy to digest. While building an AC RL Circuit in the lab, the students noticed the mylar capacitors supplied with their electronics kit had strange markings such as "102", "103", and "104". This markings identified the capacitance value. I quickly did a Google Search on Capacitor Markings and found an interested website for the electronics hobbyist or professional. Two pages that interested me the most are: Resistor and Capacitor Tables and Semiconductor Package Info.
In addition to using in an electronics classroom setting, these 2 web resources should be tucked away for Handy Cricket sci-tech and robo gadget devices toolbox as well. Enjoy!!!
Microcontrollers In The Beginning (MinTB)-Educational Initiative
Here my thoughts on how to make beginning core classes in Electronics appealing using the Handy Cricket.
To make DC-AC electronics appealing and practical to students of electronics technology programs MinTB is the educational mechanism needed. The benefits to using MinTB in Electronics Technology Programs are:
∑ The study of DC and AC Networks theory becomes appealing by showing practical applications with the aid of Microcontrollers.
∑ Tech Entrepreneurs interested in creating smart products will learn immediately how microcontrollers aid in the development of such devices.
∑ Computer Programming and Software level concepts can be introduced, thereby allowing the student to develop critical skills in problem solving and logic earlier in the technology program.
∑ Ohmís Law and Circuit Analysis techniques will be put into practice by wiring AC and DC electronic interface circuits to a microcontroller.
∑ Simple circuit interfaces can be explained and experimented with the aid of the microcontroller.
Also, AC and DC circuits can be validated by using the microcontroller with appropriate monitoring displays. This built in verification tool will quick aid the student to identifying the interface circuits are working correctly. The Handy Cricket provides and easy microcontroller applications platform because of its:
∑ Easy to wire AC and DC electronic interface circuits to is 2 IO ports
∑ Cricket and Logo Block programming languages are easy to use, thereby allowing the microcontroller to be programmed easily.
∑ Circuit monitoring can be accomplished using onboard LEDs or the external Communication Bus based 7 Segment LED Display.
The MinTB initiative can easily be incorporated within sci-tech curriculum of families who homeschool their children. AC Electronics class at ITT Tech lectures and demos illustrate how microcontrollers and DC & AC Electronics work together within the specified consumer based product. I'll have additional thoughts on the MinTB Initiative in future blogs.
LEGO Mindstorms meets the Handy Cricket!!!
As mentioned on the home page introduction:
"The goal of this site is to provide science and technology information to families using the LEGO Mindstorms, Handy Cricket, the Basic Stamp, the PICAXE microcontroller, and the TI Graphics Calculator as core education tools."
In keeping with this Mission Statement, here's a simple way of electrically interfacing the yellow programmable brick to the Handy Cricket. The key to any hardware interfacing project is finding a "hook" in which to exploit the target system for Research and Development purposes.
Sorry about the poor penmanship, using Jarnal Software is quite challenging with a Mouse instead of electronic tablet. But practice makes perfect! I have further developments of this circuit (both hardware and software components) via Reference Design. The design is minor deviation form the topic discussed in the LEGO Mindstorms Interfacing book. I'll be interested in feedback from those adventurous Sci-tech and robo gadget enthusiasts who have built and tested the basic interface circuit.