Documentation
Not only a record of projects past, the literature provides a reference for future designs.

Our practice of documenting each and every project from start to finish yields a rich harvest of material. Read on for a small sampling of our achievements, reprinted with permission where applicable.

Three-wire protocol
Simple method to interconnect very inexpensive microcontrollers to realize the potentials of parallel processing. Developed to satisfy personnel tracking requirement, but generically applicable to any multiprocessor situation. Full Text.

RFID Encoding
This article considers the minimal elements necessary to represent a useable RFID tag in a practical manner. Bitwise representation is explained along with timing and CRC validation. Some source code is also provided. Full Text.

Finalizing a Blade Sharpener
A recent project required us to finish a project that was increasingly considered "impossible" by our clients' engineering department. Stepper motor torque was weak when the AC induction motor was run, and this was the primary reason for past product failure. Other requests pertaining to motion control were also made. We delivered a solution to this client within two weeks. The result was a fully operational machine. Video

Making a 120VAC Current Sensor / Ammeter
Making a device to sense the power demands of household appliances is theoretically simple, but as with everything else the devil is in the details. Here's how Craig made a working sensor with the MTC30101 torroid. Full Text

Mote Network Modem
This document defines the RS-232 to wireless network bridge developed using Crossbow's Mica2 Mote. The design is intended to help University students achieve the benefits of wireless technology without requiring extensive knowledge of embedded programming. Full Text or Source Code.

In Black and White -- A Bar Code Decoder
Circuit Cellar Volume #104.
Here we outline the details of bar code decoding, the hardware necessary, and the software algorithms to perform the task. Software examples are written in 'C' and targeted for execution on an x86 platform.  Full Text

A Mote for Local Information Broadcasts
Of particular interest in this project is that we introduce a multipart wireless messaging scheme into our framework. Most messages using motes are atomic entities where each packet contains all the information necessary to make the packet relevant. In our information broadcast scenario, we must assemble several messages in order to provide the user with a coherent information block.
Full Text or Source Code.

A SkyeTek RFID Reader with Mica2 Wireless Plus
The RFID reader is great by itself, but combine it with the wireless capabilities of a Mica2 and you've got something to write home about. In this document, we describe our solution for RFID plus some other desirable sensing functions. Full Text or Source Code.

Understanding the FSKNet
This article introduces the FSKNet protocol. It explains why it came about and how it can be utilized for a variety of applications. Hardware schematics and pseudocode examples are also given. The network, as explained, can accommodate up to 3000 devices distributed across 30 individual systems.  Full Text

Untangling the FSKNet
This is the second article in the FSKNet series. Like all other network
protocols, the workings of FSKNet remain a mystery until directly observed during operation. This article introduces the reader to an FSK to RS232 adapter and monitoring software, FSKMON. FSKMON is a program that monitors all FSKNet throughput and presents data in a human readable format.  Full Text

WireLinks on the FSKNet
The final article in the FSKNet series, this installment focuses on the WireLink. Craig exposes packet types, data structures, and trailer registration methods. As a prerequisite you should have a fair understanding of what FSKNet is and what tools are available to monitor network traffic.  Full Text

A Mote-enabled GPS Server
In this article, Craig explains the workings of a GPS receiver that has been married to Mica2 Mote. The Mote provides both a serial and wireless interface that is easily queried and configured to work hand-in-hand with the Mote Network Modem discussed above. Full Text or Source Code.

The Mica2Dot as Proximity Sensor
Here, the Mica2Dot is being used to sense proximity to a GPS server. The GPS Server is a portable device, and the Proximity Sensor is worn about the wrist. If the two devices are separated by more than a threshold distance, an alarm will sound. Full Text or Source Code.

Universal DC-DC Power Adapter & Charger
Craig defines a programmable multitap voltage converter intendended for use in a multitude of embedded applications. The device can operate using nearly any reasonable DC input voltage and step-up/step-down the voltage as necessary to achieve a desired level. Three independent output channels are defined as well as a channel dedicated to managing rechargable batteries. Selectable batteries include lead acid, NiMH, NiCD, and LiOn. Charge source can be any DC supply including solar panels.
View Full Text.

Getting to Hardware Under Windows 95
An article explaining how to create helper VxDs so that Windows
applications could access the hardware and memory. Highlighted the parallel port and showed that it can be useful for generic IO -- 12 TTL outputs, 5 TTL inputs. Included schematics and source code.

Forcing DOS Code onto a Windows GUI
In this article, Craig demonstrated the workings of a VxD he created that allowed DOS boxes and console applications to communicate with full-blown Windows 32-bit applications. With the VxD, communications were as simple as posting messages to an application’s “mailbox.”

Programming In System
This article covers techniques for making a product programmable in the field. Covers such topics as VonNeumann vs Harvard Architecture, token execution, memory bank swapping, and Atmel’s latest series of 5V flash-based microcontrollers.