Computers & Gadgets

These days there are hundreds of vendors online selling wireless transceiver modules for transmission of wireless data. These modules are there to make wireless integration with your system much easier. The prices really vary, but so does the quality and performance.

For one of my first wireless robotics projects I went with a cheap module that I finally managed to get working, but it was a pain and had reliability problems. After working in the electronics industry for a while I learned about the importance and differences of the modulation techniques that the modules use to transmit data. Take for example wireless modems for serial UART data. The cheap modules on the market use analog type modulation. If radio interference is present during transmission the data is usually lost, and that can cause problems for many systems. Unlike the cheap modules using analog modulation, the mid-range modules all use some type of digital modulation, such as spread spectrum, which yields much better results.

Spread spectrum techniques spread the data over a range of frequencies, thereby reducing the chance of interference, and increasing reliability and data throughput. If one wireless data packet doesn’t make it through reliably, the module re-send the data on another frequency. However, there are many types of spread spectrum technologies used in wireless transceiver modules. Most popular for the mid-range quality module is either DSSS or FHSS. DSSS refers to direct sequence which locks in on one channel, while the FHSS refers to frequency hopping, which randomly jumps around several frequencies. Under certain conditions both DSSS and FHSS methods have their advantages, but when you use the high-end modules they will typically use both methods. Using DSSS combined with FHSS can offer several benefits like increased reliability, lower power use, reduced multi-path effects, and less prone to radio interference. Unfortunately, only two companies are making modules that use both DSSS and FHSS methods. I have used both, but I really recommend DataBridge modules from Starman Electric. These modules are a third of the price of the competition, and are extremely easy to setup for point-to-point wireless systems. No doubt, they will provide superior noise resistance and provide very reliable transmission of your critical data.