Upon recently stocking the BA1404 FM Transmitter IC chip, I began to build a transmitter using one and I realized that 38KHz oscillator crystals are needed, so I ordered several of them and we now stock them for your convenience. You can get yours from our store at http://mklec.com/38khz-crystal-oscillator.
About a year or two ago I discovered an iPhone app called “Sound Grenade“. It produces a very high frequency sound that is very irritating if you can hear it. I am fortunate enough to not hear it, so it was fun turning it on and watching those around me squirm and squeal about that awful noise and trying to figure out where it was coming from.
I recently began to wonder if a “sound grenade” or “high-frequency” sort of device can be made using simple electronic components. FYI, the frequency range begins at 8Khz, then progresses to 10Khz, 12Khz, 14Khz, 15Khz, 16Khz, and 17Khz. A video demonstrating this range can be found at http://youtu.be/LNjPmhbPc9I. After much research, I discovered such a circuit can easily be built using the 555 Timer and a small 8-Ohm speaker. I’m not sure what the full range is on this since I cannot hear the sound above a certain range and my wife is unwilling to help since it’s very discomforting to hear. I also do not have an oscilloscope to test it with.
QUICK NOTE: This does NOT have a pull-pin or a delayed timer to it nor is it designed to be thrown like a real grenade. The app doesn’t either and so the idea was to imitate the app’s behavior. For that type of project, you might have a look at http://imakeprojects.com/Projects/sonic-grenades/ or http://www.instructables.com/id/Sonic-Grenade-from-Mostly-Scavenged-Parts/.
The ROHM BA1404 DIP-18 IC is a truly unique chip. With this IC and a few external components, you can build your own stable FM stereo transmitter. That means you can make your own wireless FM microphones, pirate radio station, and car stereo transmitter so you can play your MP3/iPod/iPhone music through your car stereo with clarity. The great thing is this chip operates on a single 1.5 AA battery and features low power consumption. If you don’t have one yet, you can get yours in our store at http://mklec.com/ba1404-fm-stereo-transmitter-ic
There’s a few crucial external components you will need to build this circuit. I’m going to be using the circuit found at http://www.electroschematics.com/54/ba1404-fm-stereo-transmitter/. I’ll make a complete parts list soon, but the main things outside the standard components is the 38KHz oscillator crystal and the 3.5 turns RF coil.
We’d love to hear from you on your experiences with this IC and even show off your build. Please feel free to post a comment below and/or visit our Google+ Community and share there.
I’m pleased to announce a new product we’re carrying … 29mm (1-1/8in) diameter small/mini speakers. These small project speakers are excellent for audio output applications where a small, lightweight speaker is the most ideal choice.
These are rated at 8ohms 0.25watts.