Prototyping, Digital Electronics, and the Handy Cricket

This past Saturday (9/23) makes it 3 weeks into the quarter at ITT-Tech and I've only begun to show the class the wonders of electronic circuit prototyping. The Digital Electronics II course I teach focuses on the operation of binary & decade counters (Asynchronous & Synchronous), Shift Registers, PLDs (Programmable Logic Devices), and the Intro to DSP (Digital Signal Processing) using Digital to Analog (DACs) & Analog to Digital Converters (ADCs). The students are also required to do a Design Project as well. The opportunity that presented itself in this class was to show how the Handy Cricket (HC) can assist with the lab experiments as well as the Design Project. The sequential logic circuit which consist of discrete inputs, memory-processor, and electrical/electromechanical outputs is the fundamental model for computers. To make this connection the Handy Cricket is the modern versus of this digital circuit. Although posted on a previous blog, I'll demonstrate how the HC can be used as digital clock for testing their breadboard circuits. Breadboarding is a form of prototyping whereby electronic gadget ideas can easily be validated and modified. The Handy Cricket can also provide logic level inputs to digital circuits based on some external sensor wired to either SensorA or SensorB ports. I'll have in the appendix of the Handy Cricket Robo Hacks book some hybrid circuits using the Handy Cricket and digital electronics working harmoniously together in the target  sci-tech or robo gadget device. By the way, back to the writing the book!!!


LED Technology and Applications

 Last week I attended a 3 day course on LED Technology and applications at Rensselaer Polytechnic Institute's Lighting Research Institute. For 3 intensive day's I learned about:

bullet Lighting Terminology
bullet LED Technology, operation, and applications
bullet Photometry and colorimetry of LEDs
bullet LED Electrical Characteristics
bullet Thermal Analysis and Thermal Management of LEDs

 There were also 4 LED lab sessions as well:


Spectral power distribution measurement


Light output and efficacy measurement


Junction temperature measurement


Electrical Characteristics and Dimming

Dr. Narendran, the Director of Research for the LED Lighting Institute provided technical information related to the construction and operation of LEDs as well as the Business Model for this solid state lighting device. Right now, LEDs can be found in niche markets and novelty products such as Flash Lights, yo-yos, and power outage devices.  Most LEDs are used as visual indicators for data or to provide basic illumination of dark surfaces. This backlighting technique allows electronic devices such as Automotive Instrument Panels, LCD watches, and cell phones to visually operate in the dark. Bigger applications for electrical devices as Traffic and Automobile rear parking/brake lights also use abundance of LEDs for visual warning and driving safety. Narendran pointed out that LEDs will not totally replace the incandescent light bulb because of cost and heat. Although, LEDs have an electrical operating life expectancy of about 50,000 Hrs, the heat in which the "High" intensity devices generate provides an engineering challenge as well as at about $4.00 for an individual lighting device makes it quite hard to justify in the Business Model. For sci-tech and robo gadgets, LEDs are the "bee's knees" in terms of providing elegant visual indicators for analog and digital data.

As a wrap up for the 3 day extensive workshop, the class of about 30 participants were divided into small groups to design, build, and test a Undercabinet LED Fixture. This presentation was prepared with the help of my lab partner Jose Chaves of PolyBrite . I found this session of the workshop very interesting and educational as it allows the Hardware Hacker within me to explore the illumination capabilities of the Lumileds Star LED of 1W rating via hands-on construction and experimentation. I agreed with Dr. Narendran that LED applications need to be explore not only from a Product Development perspective but also from Business and Thermal Management views as well. I'll be posting additional information on this Emerging Technology in future blog entries.




Digital Electronics II and the Handy Cricket

The Fall 2006 Qtr at ITT Tech has started and the course I have been assigned to teach is Digital Electronics II. In this course I'll be presenting tech info related to counters (Asynchronous & Synchronous), PLDs (Programmable Logic Devices, Memory & Storage Devices, Intro to DSP (Digital Signal Processors), and Shift Registers. Also, as a preview to microcontrollers, the Handy Cricket will be used in the discussion of advanced digital systems. I'll also create some labs whereby the students will construct digital controllers for robotic assisted devices (RADs) as well. The Handy Cricket is the big picture item for the course because of it's use of discrete digital components that support the PIC16C715 microcontroller on the pcb (Printed Circuit Board). Saturday (9/9) was the first class meeting and the first topics discussed were 2, 3, 4, and MOD 10 Bit Binary Asynchronous counters. The first circuit for the students to build and test was a 2Bit Binary Counter. Although the circuit diagram shows the Handy Cricket (HC) acting as Clock circuit, the students used a 1Hz signal from the lab's Function Generator. I'll do a demo in next week's lecture illustrating the versatility of the HC and its application to digital systems technology. Oh by the way, my course notes and circuit materials are available to the sci-tech and robo-gadget community Open Courseware yeah know!!!!


Simple Temperature Sensor Circuit

Here's a cool little circuit that has a lot of potential for sci-tech and robo gadgets. This simple transistor-circuit can be used to detect "Hot" temperatures radiating from sources like incandescent light bulbs and hot water. The series network of the Thermistor and the 1K resistor establishes a the appropriate turn on voltage (>0.7V) for the 2N2222 NPN transistor. Upon the transistor switching "ON" the 10Kresistor current will flow to ground established through its collector-emitter junction. The 10K resistor can be replaced with 330ohm resistor in series with a LED to provide a visual indicator. I'll be posting a complete Electronics Reference Design for this circuit in a future blog entry.