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Start making own transmitters/receivers...

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adamthole

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Hello,

I have been using the Laipac 315Mhz transmitters and receivers modules in many of my projects for a while now, but I would like to start making my own transmitters/receivers so I can put them right onto the same circuit board as my project, instead of having a module sticking up. Do you have any suggestions for where to look for help/designs? Thanks
 
You could bend the pins of the modules 90° so they wodnt stick out.

Making your own can be quite hard.Especialy if you need high bit rates.

Some help from audio guru would be neded here.He designed an FM radio transmiter.
 
Yeah, i do bend them, and that helps, but it is still larger than it needs to be. I have been getting into SMD stuff, and just trying to make my devices as small as possible. They don't look that complicated wehn looking at the modules. Perhaps audioguru will know. Thanks!
 
they don't look very difficult because most of those cheap digital transmitters/recievers have all the "real" circuitry stuffed into one little metal-can device, which is specifically designed for these devices, then mainly only the larger discrete components need to be on the PCB. If you can find those metal-can devices to purchase separately, then it shouldn't be hard, but without them there would be a lot more circuitry you would have to make, and the PCB design for that additional stuff would be a lot more complicated, since it would involve a lot of sensitive RF circuitry.
 
The only VHF transmitter that I've made for about 30 years was my FM transmitter a few months ago that works pretty well. I was fixing a lousy transmitter made by someone else and copied bits and pieces from Rod Elliott's site.

One of these days I'll get into surface-mount parts and make some tiny stuff.

Hee, hee. :lol: Like the Keys Finder my daughter got on sale for 6 bucks. "Dad, can you fix this? It goes off all the time." Hee, hee. :lol:
I can't make it beep if I scream or whistle loudly. I clap my hands and jump on it and it's quiet. My daughter, wifey and TV make it go all the time. It makes Morse code beeps like SOS or something, 5 times.

It has a piezo beeper/microphone, a red LED, two surface-mount resistors and a black blob for its IC. It has two button battery cells.
I was going to make one with real filters and stuff so it works properly.
Now the Chinese are selling this junk.
 

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akg said:
Audioguru , why is C4 specified different for Europe and NA ??
FM and TV audio is broadcast with pre-emphasis, which is boosted treble, then radios cut the treble back down to normal and at the same time cut down background hiss.
The Americans started broadcasting FM first, and chose very strong pre-emphasis so that the noise was reduced agressively.
Years later, the Europeans began FM broadcasting but microphones and recorders were better and their boosted treble overloaded the transmitters, so they decided to use less pre-emphasis than the Americans.

American FM radios in europe have too much treble cut and sound muffled. European radios in America have too much treble boost and sound shrill. :cry:
 
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