4

I'm looking for a way to get an app running on a laptop to communicate with an app running on a Raspberry Pi. This is a home/hobby project, so looking for inexpensive COTS hardware and open source software (drivers, etc.) every step of the way.

Ideally, I could find a transceiver that also had a USB port on it, and I could plug it into my laptop. Then I could find another receiver that could connect (USB or otherwise) with the Raspberry Pi. Then I could deploy my client app to the RPi, my server app to the laptop, and the two could speak to each other.

What kinds of transceivers could I use for both the laptop and the RPi device? What other considerations am I (possibly) not thinking of here?

  • possible duplicate of Cheap COTS identification system that integrates with Raspberry Pi – lenik May 14 '14 at 16:12
  • @lenik - I asked this other question, and please note that they are 2 distinct, separate questions (not dupes!!!). This question is about selecting transceivers that would work with RPi. The other question is about making an RFID reader work with RPi. Two totally separate questions. The only commonality is their title. – zharvey May 14 '14 at 16:19
  • 1
    Nice question. The answer is any transceiver. And because of that I think it is opinion based. Please do some research on what is out there and what fits your needs. I mean you could use FM if you wanted, or 433Mhz Serial for the slightly less cost than Bluetooth Serial. You can even make your own sub gigahertz wifi serial out of a coil and simple IC for 50 cents. The possibilities are endless. – Piotr Kula May 14 '14 at 16:26
  • Thanks @ppumkin (+1) - but I have a feeling you didn't read my question entirely. I need 2 transceivers (possibly): 1 that will attach to my laptop via USB, and another that will attach to the RPi in any way, shape or form. And they need to be able to talk to each other. Thoughts? – zharvey May 14 '14 at 17:46
  • Ahh sorry. I never noticed your comment till now. Because all the transceivers mentioned use UART, you should be able to find USB alternatives, since it will be the UART connected to a FTDI USB controller. Its still all SERIAL data just packaged differently. For 2.4Ghz you can get Texas Instruments CC2530 USB Packet Sniffer- I have this its great, it can even scan 433mhz. – Piotr Kula Jul 15 '14 at 17:19
3

The simplicity of these is that its a transparent UART channel so you can add as many transceivers as you like and all the nodes will get the data. You need to create some kind of simple model based on JSON, where you embed an ID, the NODE you are interested in a multi tenant environment, and the command or data. JSON is easy to read, compressed well when theres loads of its better than XML, or any other custom models.

{nodeid: ABC123, temp: 12, humid: 15, wind_speed: 0, wind_direction: 25, etc ...

These are fairly cheap and have built in stacks to modulate demodulate the data. With all

2.4Gigahertz

For quite a while these were pretty expensive to produce but recently it looks like the market got flooded with an IC that can be made cheap and easy. This 2.4Ghz module can receive and send, on selected channels, which do not interfere with WiFi because of isolation.

These can be found for about £1.40 on eBay. The only drawback is that it is not easy to tune the signal strength but it is much more stable than sub giga when in range.

enter image description here

SUB Gigahertz

Cheap and loads of them out there. Some countries allow you to amplify signal to cover miles and miles of directional wireless connections.

You can get 433mhz serial links found under 433mhz Arduino Radio or similar. Make sure to get TRANSCEIVERS, as some are just receivers or transmitters.

This is a more directional transceiver - Better range in a straight line but works omnidirectional too. The obvious drawback it needs some more space for the antenna

enter image description here

There are also ones with an embedded coil. They work well too. I can't comment on min or max ranges but we are talking about 10-30metres, maybe more.

enter image description here

You can use even cheaper transmitter if bought in bulk on devices like sensors, where they just send data every 12 hours, or on a trigger, etc. And use only 1 receiver, because all the data is on a single 433mhz channel. Beware that other devices, not yours might be transmitting on these channels too, car remotes, garage doors, heat meters, etc..

The drawback is security is virtually non existent and to secure secret data, you should not use any of these modules on this page.

In my opinion, these are the simplest and cheapest way to do it.

0

I would suggest that connecting with Ethernet (preferable) or Wifi is inexpensive and simple. I have several Edimax wifi USB receivers, which required no driver configuration: the receiver had to be required with AP login info. With wifi, it is simpler with no configuration

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service, privacy policy and cookie policy

Not the answer you're looking for? Browse other questions tagged or ask your own question.