Friday, May 26, 2017
Head Move Donkey V02: progress
After this post on my donkey update I learned some things, much of it from Adafruit Support on the forum in this thread.
First I was concerned with a statement in the MusicMaker Learning Guide "Don't forget to make sure you have a good strong 5V power supply - especially if you're using the 3W 4 ohm speakers! " It turns out that I was able to do what I needed with the 3.7V LiPo--I noticed no difference in output using the 5V 2A wall wart. I was even able to run everything off the 4xAA battery pack (using NiMHs only give 1.2V each, 4.8V total). However, when I added the second Servo. I needed 2 power supplies.
Second I had trouble getting decent volume from an 8Ohm .5W speaker. I was directed to use 4Ohm 3W speakers. I tried an 8Ohm 2.5W speaker I took out of a CRT television amd that was fine, but it's too big for the donkey. I got some 1.25" 4Ohm 3W speakers off ebay, but they did not produce enough sound. The smaller Adafruit version did the trick.
Third, I cooked an SD card and a MusicMaker. I think it was while I was experimenting with power options...I may have mis-connected something. First symptom was that it could not initialize the SD card. I replaced it, and it got past initialization and said it was playing music but it wasn't. Back to Adafruit for replacement board.
The reason for the second Servo is that I decided to move the donkey's tail, too. I move the Servos in opposite directions, just because for grins.
Here's my appearance with the project on Adafruit's Show and Tell. I'm on from about 11:30 to 14:00.