Logic level shifter

The Arduino normally runs at 5 V. The pressure sensor and accelerometer run at 3.3 V. The sensors could be damaged by 5V. What to do? Use a "logic level shifter"! It converts between 3.3V and 5V signals (bi-directional), so it works well with the I2C protocol.

The logic level shifter board hangs off the end of the 17 row mini bread board, hence the cluge of gator clips for this checkout (note to self: if ever make perf board or PCB include at least 20 rows). Also pictured is Arduino and Fritzing running on Ubuntu (an open-source hoe-down!).