Wireless Transceivers

A project log for The Open Woodwind Project

An Electronic Aerophone with focus on usability as an instrument.

J. M. HopkinsJ. M. Hopkins 09/16/2014 at 10:480 Comments

Currently I'm using the Polulu Wixel 2.4GHz transceiver pair as my device for communication. Due to the ever present noise associated with that band, and it's limited range I've been thinking of changing the transceivers to a higher power.

One of the nice things about the Wixels were their power usage, and upgrading to a 433MHz device will start eating into battery life.

The APC 220 RF modules have a much increased range, and though the available baud rate is lower, still fits within MIDI standards.

Ranges of 1km at full power are achieved with line of site, however, a lower power well suffice for my needs and help save battery life. At around $30 for the set, it's not a bad deal either.

With the addition of sma connectors for the antenna connection I'll change from a trace antenna to a 1/4 lambda for the instrument and a 5/8 lambda for the base station. The reason for the differing length for the two is the radiation pattern. 1/4 gives 2db and a higher angle of radiation (useful for when the instrument is moving around), and the 5/8 gives 3db but with a pattern much lower. This gives a 16.3 inch antenna for the base station and a 6.88 inch antenna for the instrument. The antenna well be hidden on the inside.