Knowhere

Well, I gave up on making my own radio and figured using a module would be only slightly more expensive, much more reliable, and would enable the device to be much smaller than before, which are all good things on the whole I'd say. I still felt like I've given up though, even though my brain says that I just made the rational decision necessary.

We had originally planned on using a power radio because we had researched crystal radios and found that they needed really big coils and even bigger antennas. But recently, we discovered that they actually made pocket-sized crystal radios back in the day, and we plan to build one of those and try it out to see if it will work with our idea. It still has a relatively long antenna, but this can be shortened by adding a trickle of the ATtiny's power into an ampifier. Another problem we went around is the germanium diode. When making a low-power radio, a germanium diode is a necessity. These are both relatively expensive (usually more than one or two dollars) and only available online (RadioShack stopped carrying them a while ago, as well as most electronics vendors). We found many sources that claimed that LED's work nearly as well as germanium diodes, and they're extremely cheap and easy to find. We happened to have a few lying around (who doesn't?) and we plan to build this radio soon. We've left behind trails of radios we built that wouldn't work and the mangled remains of perfectly good commercial radios we took apart to find the secrets inside. Hopefully this will be the solution we were looking for.

Success! We (or rather, Surya I should say), finished the GUI for the Raspberry Pi! The finished screenshots are up on pictures and the code is on GitHub. Additionally, the code for the ATtiny is also finished. The only thing left is the radio receiver, which is still proving slightly problematic although I have hopes of finishing it this weekend.

Well, we've figured out how to remove that extra step of modulation and demodulation that exist in standard AM and FM signals. Our method is called PM, or Pulse Modulation, and it's all binary. Unfortunately, the darn radio doesn't want to work. We'll figure it out. Eventually. Or bribe smarter friends into figuring it out for us. On the bright side, we finished the entire GUI and transmission code for the transmitter (Rasbperry Pi) in one go, and the finished, but untested code will be on GitHub.

Well, we found out a bit too late there is no tuning capacitor in a 50 mile radius of where we are. And unfortunately, today being a Sunday, we can't get it shipped quickly either. So we're going to pillage one out of a radio, along with a few other handy components. Ideally, in the finished product, you would have a fixed, non-variable capacitor. We're finding what exact capacitance we need to make the radio receive 88.1 (or your channel of choice) properly, then ordering that capacitor from an electronics warehouse.

All of us have reasonable experience in programming and hardware, but didn't know anything about radios until we started this project. We're aware that FM radios go through a step of modulation and demodulation and this isn't necessary if you are sending raw digital data, like we are, but we're not entirely sure how to bypass it. If it works with the extra step, great, but in a perfect world, we'd eliminate the extra complication.