You can add your name to a splash screen, develop a new product feature, or — living life on the edge — rewrite the whole shebang and make an entirely new product: the sky’s the limit when hacking firmware. There is one very important caveat, though: if you don’t know what you’re doing when tinkering with firmware, you could destroy the product. In this introduction to firmware hacking, let’s try a simple modification. We’ll reformat the output from the USB Weather Board v1 so that it can be meaningfully displayed on a serial-enabled 20×4 LCD. In its stock configuration, the output from the USB Weather Board is a continuous string of numbers, like . Not very friendly, is it? We’ll modify the firmware so that the output is easier to comprehend. Something like: . But wait; there’s more. We’ll also add an LCD for displaying this new output and a battery power supply, and wrap everything up in a handheld enclosure. The result is a portable, handheld personalized weather forecasting system. Or, as I’ve dubbed it: the 4Caster 1000. TIME: 3 hours COST: $160.73 DIFFICULTY: easy PARTS USB weather board v1 (SparkFun Electronics #SEN-08765; $99.95) Serial-enabled 20×4 LCD (SparkFun Electronics #LCD-00462; $32.95) 5V DC-to-DC step-up (SparkFun Electronics #PRT-08248; $10.95) 6x headers (SparkFun Electronics #PRT-00116; $2.50) SPST push on/off switch (RadioShack #275-011; $1.99) Project box (All Electronics #1593-YBK; $4.95) Hookup wire (RadioShack #278-1224; $5.99) AA battery (locally available; $.50) Optional (might already be attached to some USB weather boards): 2×5 AVR ICSP male header (SparkFun Electronics #PRT-00778; $0.95) STEPS Take your portable, handheld personalized weather forecasting system with you wherever you go. Just press the pushbutton on the outside of the project box for a quick snapshot of your current weather conditions. By monitoring these weather stats from your hacked firmware, you might be able to make a quick “guess” about upcoming weather changes. Please note: spurious characters might sometimes appear on the LCD. For example, all “Ps” will suddenly change to “@.” Or, a “0” (zero) will drop out. This distasteful effect usually disappears within 1-2 seconds.
