What is the purpose & intended usage of the connections on the Spark core's pins labeled A1 & A2?

[Stephen Germiller]

What is the purpose & intended usage of the connections on the core's pins named A1 & A2? They seem to be used with the microphone and/or amplifier? I ask because the stock hardware setup for the mic needs significant changes. Even when used with the code on "Purple Rain" by "momo" and with a jury-rigged externaly mounted stock mic.  

My main pcb does not have a version number and would appear to be from before the November rev 1.0 maybe? 

[bie...@gmail.com]

I agree, T

he stock microphone setup is not working at all.... Only very loud noises are picked up.

[Shawn Frayne]

Hi all - we've definitely found variability in the responsiveness of the mics in the Christmas Cubes.  Some work well and some don't.  It's likely the result of ultrasonic cleaning of the baseboards, which led to a decrease in sensitivity of some of the mics over time.

Alex, Samtim, and I are working out a solution and will post up here on Wednesday.  (of course, any other ideas or test data are always super welcome - please post here!)

-Shawn

[TECH_GEEK10]

Is it possible to have the mic itself not installed in the factory? I think a simple way to solve this would be to have the user install the mic into some sort of connector like this: https://www.sparkfun.com/products/10571

[Shawn Frayne]

Tech_geek10, yes that's possible.  We definitely did not expect the ultrasonic cleaning of the base PCB to have an impact on the mic performance, and all boards passed a full sound check after cleaning and before we shipped -- but there is some (possibly) moisture-related degredation of performance that happened over the course of a couple weeks, because in some of the Cubes in our lab we are now seeing the lower sensitivity that you and a few other Christmas cubers are finding.

So...yes, a snap-on mic like you suggest is definitely a possibility for the next run, or soldering on the mics after the ultrasonic cleaning process is complete.

p.s. If you're experimenting with external mics, you should be able to input your signal at the A2 pin of the Spark Core, but you will need to amplify the signal going in.  (one of the things we're testing is whether a two-stage amplification of the current mics will give better results)

-Shawn

[TECH_GEEK10]

A mic that uses a connector like the one I linked would also allow users to more easily modify where the mic is located. Or to swap the mic for another, and possibly to add a additional amplifier to the mix.

[TECH_GEEK10]

I did as you said and it now actually senses noise, but not in a good way. I tried screaming & tapping the case, but only get 1 led on the graph :( Before it didn't even respond unless I tapped the mice itself.

[TECH_GEEK10]

I would try adding the mic after wash, however you should break-out the mic's pins and put a solder jumper that disconnects the stock mic so users don't need to deslolder the mic to use the breakout pins to get access to the amp(s).