Wireless Microphone in a Wall Box
OK,
I have been at this for some time now and I can finally post my SUCCESS in designing a wireless microphone for my personal HA installation, oh yeah, did I mention it's cost effective too?
I have looked and looked for this type of device and I haven't been able to locate one, reasonably priced, so I made it myself.
I started with a Radio Shack wireless 49 MHz FM Microphone system (Catalog Number 32-1221B). I have used this model because it is VERY inexpensive compared to a higher frequency unit, ie: 170MHz wirelss mic's. I know a bunch of people are using this mic system,
http://www.geeks.com/details.asp?invtid=WM-603-N ,
It should work just fine for this project, as long as the transmitter fits inside the wall box.
Now let me say this, The less expensive model (32-1221B, a 49MHz system) that I am using for this write up is not NEARLY as good for range as a 170MHz system. The 170MHz system is used for stage performances, so the range is MUCh greater, AND the 170MHz system is not as prone to interference as the 32-1221B, primarily because the 170MHz range is not as openly used as the 49MHz band.
I have gotten up to 150 ft. with the 32-1221B (the manual says up to 200ft... yeah right...) and that covers pretty much my whole house. ah yeah... The only drawback is that you can only use one mic at a time. No biggie, I've put a momentary contact switch in-line for the power so I can address each mic as needed. It works like a champ, and doesn't draw any power until I hit the switch.
Now, the fun part. I have managed to install the entire unit into a wall box. This includes the battery holder and transmitter! lol, truly a wireless design! I've set it up in a post-build box so it goes right where I want it and no concerns about finding an ac plug to supply power, although this can be modified to accept a wall wart if you really want to use one.
I took the mic/transmitter apart and separated the transmitter and microphone. I saved the mic for use later. I took the transmitter and hot glued it to the bottom of the wall box. When the transmitter is out of the actual casing it comes in, it fits perfectly in the wall box. I soldered connections to the leads on the transmitter, for the mic input, and put a 1/8in. female connector (mounted in the wall plate) on the input side.
Next, I soldered a momentary contact switch between the negative (-) coming off the battery pack and the negative (-) contact on the trasnmitter. This way the transmitter only gets power when the switch is pushed and then disconnected when the switch is let go. The batteries last a lot longer this way.
Next, I took the microphone that came with the unit and trimmed the wire on it down. Then I soldered the microphone to a 1/8in male adapter (274-286). This gives the mic a very short lead, about 2 inches. (don't worry). You can use ANY microphone as long as it's 1/8 in. male.
Now, the fun stuff. I have used a wall plate, 6 port type, to make my external connections. One connection is the momentary switch, one is a 1/8in female connector. The top two slots are for the batteries. The other two are for future enhancements (ie. an led, external antenna, etc).
I use 2 Radio Shack 270-401, or 1 270-382A, AA battery holders for the power requirements. I had to make some slight modifications to get them to work inside the wall box, however, they work great once you find the sweet spot. I series wired the battery compartments, then wired them to where the respective contacts are on the transmitter.
Once the wallplate is built, simply put the microphone into the 1/8in female connector, and press the button.
Voila! A self contained wireless microphone.
Guy
p.s. Pics to come, as soon as I can get my camera working again.
p.s.s. The 170MHz system is unbelievable for range and accuracy.
I have been at this for some time now and I can finally post my SUCCESS in designing a wireless microphone for my personal HA installation, oh yeah, did I mention it's cost effective too?
I have looked and looked for this type of device and I haven't been able to locate one, reasonably priced, so I made it myself.
I started with a Radio Shack wireless 49 MHz FM Microphone system (Catalog Number 32-1221B). I have used this model because it is VERY inexpensive compared to a higher frequency unit, ie: 170MHz wirelss mic's. I know a bunch of people are using this mic system,
http://www.geeks.com/details.asp?invtid=WM-603-N ,
It should work just fine for this project, as long as the transmitter fits inside the wall box.
Now let me say this, The less expensive model (32-1221B, a 49MHz system) that I am using for this write up is not NEARLY as good for range as a 170MHz system. The 170MHz system is used for stage performances, so the range is MUCh greater, AND the 170MHz system is not as prone to interference as the 32-1221B, primarily because the 170MHz range is not as openly used as the 49MHz band.
I have gotten up to 150 ft. with the 32-1221B (the manual says up to 200ft... yeah right...) and that covers pretty much my whole house. ah yeah... The only drawback is that you can only use one mic at a time. No biggie, I've put a momentary contact switch in-line for the power so I can address each mic as needed. It works like a champ, and doesn't draw any power until I hit the switch.
Now, the fun part. I have managed to install the entire unit into a wall box. This includes the battery holder and transmitter! lol, truly a wireless design! I've set it up in a post-build box so it goes right where I want it and no concerns about finding an ac plug to supply power, although this can be modified to accept a wall wart if you really want to use one.
I took the mic/transmitter apart and separated the transmitter and microphone. I saved the mic for use later. I took the transmitter and hot glued it to the bottom of the wall box. When the transmitter is out of the actual casing it comes in, it fits perfectly in the wall box. I soldered connections to the leads on the transmitter, for the mic input, and put a 1/8in. female connector (mounted in the wall plate) on the input side.
Next, I soldered a momentary contact switch between the negative (-) coming off the battery pack and the negative (-) contact on the trasnmitter. This way the transmitter only gets power when the switch is pushed and then disconnected when the switch is let go. The batteries last a lot longer this way.
Next, I took the microphone that came with the unit and trimmed the wire on it down. Then I soldered the microphone to a 1/8in male adapter (274-286). This gives the mic a very short lead, about 2 inches. (don't worry). You can use ANY microphone as long as it's 1/8 in. male.
Now, the fun stuff. I have used a wall plate, 6 port type, to make my external connections. One connection is the momentary switch, one is a 1/8in female connector. The top two slots are for the batteries. The other two are for future enhancements (ie. an led, external antenna, etc).
I use 2 Radio Shack 270-401, or 1 270-382A, AA battery holders for the power requirements. I had to make some slight modifications to get them to work inside the wall box, however, they work great once you find the sweet spot. I series wired the battery compartments, then wired them to where the respective contacts are on the transmitter.
Once the wallplate is built, simply put the microphone into the 1/8in female connector, and press the button.
Voila! A self contained wireless microphone.
Guy
p.s. Pics to come, as soon as I can get my camera working again.
p.s.s. The 170MHz system is unbelievable for range and accuracy.
Attached Files