318MHz Oscillator?

JonnyMac

I'm not an RF guy, so I'm hoping one of my forum friends can help. I'm helping a young colleague with cloning his garage door opening. This system using 318MHz. We don't need a lot of power, just something that can be gated with a small microcontroller.

jmg

JonnyMac wrote: »

I'm not an RF guy, so I'm hoping one of my forum friends can help. I'm helping a young colleague with cloning his garage door opening. This system using 318MHz. We don't need a lot of power, just something that can be gated with a small microcontroller.

If you want to build an oscillator, you could try something like a SAW resonator
https://www.mouser.com/Search/Refine?Keyword=RO3118

Or, a more complete cased solution might be what you are looking for ? (something like ?)
https://www.electrodragon.com/product/remote-controller-315mhz/

erco

315 and 433 MHz TxRx pairs are among the cheapest things on Ebay: https://www.ebay.com/itm/263458011149

Useful info at https://www.romanblack.com/RF/cheapRFmodules.htm

kwinn

Perhaps a propeller chip outputting a 106MHz square wave (318MHz is the first odd harmonic) would work. I know a 555 timer would interfere with AM reception due to all those odd harmonics so it might be worth trying.

Peter Jakacki

You can pickup 318MHz SAW resonators such as the ro3118 from Mouser for around a dollar, just add a couple of transistors and let the pcb track be the antenna.

Here's a circuit an image of the other side of a SAW resonator pcb I found on the interweb thingy.

Bean

Jon,
You might be able to generate a 106MHz squarewave and get enough energy on the third harmonic.

Bean

JonnyMac

@Peter: I found that, too, and am probably going that direction as I want to keep the parts count very low -- this is a learning project for my colleague. I wrote the code for an ATtiny85 while he watched and we verified the proper timing with a 'scope.