DIY Pointless Beacon Project

I, Scott Harden, in my infinite restlessness and my limited sanity, hereby declare my next [potential] project. The idea is still in the earliest stages of development, and I have much to research (for example, I don’t even know if it’s legal) but it’s a cool idea and I want to try it. I know I’ll learn a lot from the project, and that’s what’s important, right? So, here’s the idea. I want to build an incredibly simple, low power radio transmitter that broadcasts data on a fixed frequency. Data is provided by (you guessed it) a picaxe chip! What data will it transmit? I’ll tell you! It could transmit… uh… err… um… okay it doesn’t really matter and I don’t even know, I just want to do this project! Maybe temperature and light intensity data or something. Who cares. Anyway, I want to put this whole deelibopper (temperature and light sensors, picaxe microcontroller, and transmitter) into a drybox (pictured). Once properly closed, this box will keep everything in pristine working condition by protecting against rain, heat, snow (not that we get much of that in Orlando), hurricanes, and perhaps even Florida panthers and bears (oh my). I’d make a glass (or plexiglas) window on the top so that light could get in, hitting solar panels, which trickle-charges the battery housed in the device as well. Pretty clever, huh?

My idea is to keep construction costs to a minimum because I’m throwing this away as soon as I make it. That’s right! Throwing it away. Parting with it – perhaps forever. My goal is to make it work so I can toss it in some random location (I’m thinking hidden on the roof of some building somewhere) and see how long it will run. Days? Weeks? Months? Years? How cool would it be go go to dental school, come back ~5 years from now, and have that transmitter still transmitting data. Super-awesome if you ask me. I’ve been poking around and I found someone who did something similar. They built a 40mW 10m picaxe-powered beacon (see photos and circuit diagram).

See the PICAXE chip in the center there? Remember, my ultimate goal is to learn from this project. I understand the basics of radio theory and amplitude and frequency modulation (AM and FM), but I’ve never actually built anything that does this. Yeah, I know, I could build a SoftRock radio like everyone says to do, but my educational grounding is in molecular biology. I know little about circuit-level electronics, electrical engineering, and radio theory… so my plan is to start small. This project is small enough to attack and understand, with a fun enough end result to motivate me throughout the process.