Types of technology for short distance, low latency, secured, small (1-2 bytes)

Hi all,

I'm trying to motorize a pair of blinds that are outside my home, from within my home. The motors and stuff are outside, but I want to transmit the signal from within my home. The 2 boards are pretty close though!

Essentially, I have a wireless board hooked up to a few buttons, and when I press each button, I want a different byte to be sent to the other arduino to control the motor.

Key aspects are:

  • Low latency, no more than 50ms.
  • Reliable connection, as little dropped packets as possible? No idea what metric encompasses this.
  • Secure connection, ideally, some method of pairing devices like bluetooth? (Wouldn't want someone else to control my blinds :D)
  • Distance of around 50cm apart.

I tested out 433MHz RF modules with the arduino but I kept having dropped packets, maybe I was doing something wrong, but I also looked at Bluetooth and XBee 2.4Ghz. Leaning toward bluetooth at the moment for cost considerations, but was wondering if the experienced people here had any suggestions before I dived in and bought another chip to try!

Cheers.

As requested, a suggestion. I use the NRF24L01 radios quite often. See Robin2's simple nrf24 tutorial..

Bytes? You want bytes? I would think that a couple of bits would be enough. "Up" and "Down".

I would use a 433MHz transmitter+receiver for this. Maybe one that has 2 buttons, originally intended for 2 garage doors. The receiver will have 2 outputs that can go to the Arduino controller next to the motors. 433MHz with "rolling codes" can be secure. At least secure enough to be used on a garage door which accesses the house.

Can you not run a wire ?

A pair of 433MHz modules will probably cost less than the drillbit to drill through the wall.

MorganS: Bytes? You want bytes? I would think that a couple of bits would be enough. "Up" and "Down".

I would use a 433MHz transmitter+receiver for this. Maybe one that has 2 buttons, originally intended for 2 garage doors. The receiver will have 2 outputs that can go to the Arduino controller next to the motors. 433MHz with "rolling codes" can be secure. At least secure enough to be used on a garage door which accesses the house.

I wanted some control in terms of distance, so was wanting to send like 1 or 2 to denote meters. Thanks for the suggestion about rolling codes! I'll read into it.

Anyway, i decided to continue working on the 433mhz chips, after I attached a 17cm antenna they performed pretty well with far less dropped packets! Will try to implement rolling code as MorganS suggested!