Teensy 4.1 + audio as test signal generator


Well-known member
Bottom line question: Does anyone know of issues in driving DC-to-kHz signals with a Teensy audio shield?

I've been involved in a multi-channel (64-channel) analog data acquisition project and want to propose a regression / system test platform to our management. We have had great success in using the T3.1 DAC to produce single-channel output for validating basic functionality. That said, we have not yet built a test platform to validate a completely configured system repeatably. (Insert whining about not being a federally-funded research lab here...)

I was thinking about using a stack of T4.0 or T4.1 and audio shields. The signals we measure range from DC to several kHz, so I am thinking of using the line outputs of the audio shield, removing the high pass filter capacitors to allow output to range down to DC. We expect to route the output through an amplification stage and resistor network to produce the test signals driving our existing input. DC bias coming out of the audio shield is acceptable, and we are driving a known high impedance circuit so we're not trying to drive "significant" DC power out of the audio shield.

Does anyone on the forum have practice with the shield as DC-to-audio frequency signal sourcing? Are there any "gotchas" that we should be aware of?

We have an existing toolkit to manage comms, precision time-sync, and system management, and our firmware is based on NXP K60 and K66 parts. Most of the heavy lifting for controlling/driving the digital side of this work is already in place. All I need is to promise repeatable analog signal production given consistent input datasets.