Errata

Isolate speaker cinch socket

Any contact between the outside of the Cinch connector (speaker connector) and the metallic housing creates a short circuit on the audio amplifier output. Luckily, the audio amplifier has short circuit protection so there is no damage to be expected, but the audio signal is shut off. Either increase the opening in the housing back plate, or slip a short ring of heat shrink tube between connector and housing.

AD converter P/N and voltage divider

Resistors R1 and R2 have been mixed up in the bill of material, These two resistors build the voltage divider for the A/D converter. Correct is R1=10k and R2=120k.

The bill of material and schematic referenced ADS1110 as A/D coverter, but gave a Farnell P/N for ADS1100. The ADS1100 works, but with slightly lower accuracy and a different scaling factor in \opt\conf\sensord.conf. For the ADS1100 calibration factor is around 736, for the ADS1110 and its internal reference expect a calibration factor of around 1200.

Sensorboard PCB tracks too close to mounting hole

On the first sensorboards produced one PCB track is too close to mounting holes of the POM block. The installed M2 nut and washer can create a short circuit to ground and shutdown I2C communication. This can be easily fixed with an isolated washer (or a drop of Epoxy).

Misleading Fotos in the Assembly Guide

List of wrong fotos in the assembly guide (Unfortunately the original document is missing!)

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