Audio Interference from Wi-Fi (?)

pdteam commented 7 years ago

Hi there. The Particle Photon Wi-Fi Audio through DMA works very well but when I assemble it as indicated I get really bad interference from what seems to be bleed over from the Wi-Fi. Here is a link to how this sounds: https://soundcloud.com/mademill/transmitted-audio-with-interference-from-wifi

Did you encounter this issue?

Things I've tried:

I have tried it on 3 different Photons and 3 different microphones (this type https://www.adafruit.com/product/1713) as well as other microphones from Adafruit and Sparkfun with built-in amplifiers. Different types of mics were quieter as they don't have the automatic gain control but the interference was there throughout.
Using different power sources for the microphone and the Photon with a jumper for a common ground. This was the most effective by eliminating around 60% of the noise but results in a much bigger circuit because I need separate power sources / charging etc.
I've tried USB power and Li-Po battery power. Doesn't seem to have any difference.
Moved the circuit away from other possible other sources of interference (computers, lights, fans, etc.)

The interference makes the audio unusable for most use cases. Please let me know if you have encountered and what steps you might have taken to resolve.

Many thanks,

Janak

taospartan commented 7 years ago

Did you manage to solve this issue? i'm experiencing exactly the same, tried everything i could think of but utimately looks like a hardware issue.

pdteam commented 7 years ago

No never solved it. I've tried every combination of alternate boards to alternate speakers. I've tried it on the breadboard and with a soldered circuit. Recently I've switched back to an Adafruit ATWin1500 Feather wifi board which after some initial testing using the onboard ADC and Direct Memory Access (DMA) is able to transmit without this interference at all. There are a few other issues around buffering that I'm still working with but it's shown me this is likely a Photon architecture problem.

taospartan commented 7 years ago

I've found that by using differing usb power supplies the effect was either reduced or increased, but never totally eliminated. Seems strange how simple use case can have so many issues.

taospartan commented 7 years ago

Solved the problem for me by setting WiFi.selectAntenna(ANT_EXTERNAL) and fitting an external ant!

pdteam commented 7 years ago

I have tried the same thing but it sounds identical. I put that line of code in the setup function. Can you share the code you are using?

https://soundcloud.com/mademill/particle-photon-audio-interference

Here is a sample of how it sounds still.

pdteam commented 7 years ago

Actually I take it back. The antenna was still in close proximity to the microphone. Removed them and it sounds great. Gave them a separate power supply and it sounds even better:

https://soundcloud.com/mademill/particle-photon-audio-interference-fixed

Thanks for finding that!

taospartan commented 7 years ago

No worries, the mic amp i was using was auto gain so i turned the gain to its lowest setting to improve the quality also.

rickkas7 / photonAudio

Audio Interference from Wi-Fi (?) #3