Nuts & Volts Like 418 mhz Radio Transmit Receive Experiment

microcontrolleruser

Here's a project for someone looking for an 'early days' 'grind it out' one

This is way pre Zigbee.It's the bottom of the ladder.But it's simple.

Here are the modules.

http://www.futurlec.com/Radio-418MHZ.shtml

Have fun!

Publison

Moved to General Discussion as it doesn't reflect Stamp 1 chips only. Also changed title to reflect the correct frequency, previously 410).

erco

433 Mhz types are a dime a dozen.

https://www.ebay.com/itm/5pairs-433Mhz-RF-transmitter-receiver-Module-kit-ARM-MCU-WL-diy-wirelessP-T/182870461599

Publison

Agree. 418 is not used that often.

Mike Green

Also, with these simple radios, there's no error checking unless you build it into your application. That's certainly doable, but it's more work and newer radios have error checking and correction built in.

microcontrolleruser

Fixed title of post.

Believe there are 418 mhz articles in there.They may different devices though.

Stamp articles or columns from that magazine in Parallax archives say 1998.

Using these modules is from about that era.

They are so stone simple what's there not to like?

Mike Green

... "what's there not to like?"

They're just not reliable enough due to the lack of error checking. There was a thread of messages recently from someone who was using similar 433MHz devices. They didn't seem to work. After some discussion and checking, it was determined that there was too much noise in the area. If you live out in the country away from high voltage powerlines and other sources of RF noise, you might do quite well with these simple transmitter/receiver pairs. For most people, you would do much better with a pair of xBees or Parallax's WX WiFi modules or other ESP8266-based WiFi modules.

microcontrolleruser

Thanks Mike

'They're just not reliable'

That was covered in first line of post.

This is grab the datasheet and start coding stuff.

Not for the faint hearted.

Anyhow.If somebody wants to see how it was like in the 'first time out of the box' microcontroller craze then go for it!

We're doing it in assembler.Even have the sample program.

Somebody can use the Parallax units in 2004 catalog from the other post if they want to.

erco

IMO these are fine for experimenting and bit-banging some data. Sort of a rite of passage for any coder, it will make you appreciate real fast data transfer with error checking. If you come up with your own data protocol, you have to code the transmitter and receiver seperately. That also builds character!

The limiter is that the radio link quality varies. Most are only a few feet, but I have one pair that got ~200 feet. If you get that 5-pack, you have to test EACH transmitter and EACH receiver to pick the best one(s).

The antennas are absolutely critical. The short spring antennas sold are useless. Here's the best one I found so far (but I sure wouldn't put it INSIDE the metal box shown.

http://www.instructables.com/id/433-MHz-Coil-loaded-antenna/

Also watch this video:

microcontrolleruser

Erco

That was definitely a worthwhile video.Thank you.

Our goal is features that add 'scope' or capabilities to our micro experiments.

Or in plain words make them interesting to us.

Just sending and receiving will keep me occupied.

Wireless is a goodie!

localroger

I have a handful of those 400 MHz tx/rx pairs and was trying to make them work for a project when the ESP8266 hackers finally got NodeMCU and Lua working. That was so much easier and worked so much better I never looked back.

microcontrolleruser

Thank you Localroger

'so much easier and worked so much better'

Will file that away for a 'better' 418mhz.

We are basically testing stuff so no harm no fowl if it is not the greatest.

It's for a fairly large tank.About two feet long and 8-10" wide.Need room for clunky boards.

Actually it willed be wired remote first time.

418hz will probably be stand alone project.