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.

Sunday, May 7, 2017

49 States!

I've been working HF for just over a year, and have been looking forward to qualifying for the ARRL "worked all states" (WAS) award.  After starting digital modes in February, I got up to 48 states, leaving just Maine and Hawaii.  I did not think ME would be a problem, since I live in Massachusetts, but it proved to be difficult.

This weekend is the New England QSO Party, so I figured that this would be my chance. I am not hearing a lot on 40 meters today (the most likely band for me to hear ME on), but I did get 1 ME confirmed now I just need Hawaii.

Any HI hams out there wanna help me out?

73, W1LEM

Monday, May 1, 2017

Head Move Donkey V02 in-process

Adafruit Feather M0, with MusicMaker and PWM/Servo FeatherWing stacked, running the Head Move Donkey code: plays
"Donkey Serenade" while moving the servo about 60 deg right and left to move the head.
As described in detail in this post, I recreated a wind-up toy that I bought for my daughter (an infant in 1978) with a Pro Trinket 3V and other components.  In the 2.5 years since, I've gotten a little smarter and the available technology has gotten a lot better, so I thought I'd try a version 2.  The biggest difference is that I needed fewer components. 
Donkey V01 
In the original, I needed an SD card reader, an amplifier, and a PWM/Servo Board. I still need those things, but the Adafruit Feather System makes it a lot simpler, eliminating most of the wiring and some of the code.  Also the Feather uses a ATSAMD21G18 @ 48MHz with 3.3V logic/power and 256KB of FLASH + 32KB of RAM while the Trinket uses the ATmega328P  at 12MHz with 28K of flash, and 2K of, the M0 is much more powerful.

Power management is slightly different. I was able to power the Trinket from a 4xAA battery pack, using the 3V output to power the SD card and the 6V to power the Amp and servo driver.  Logic levels were not a problem.  I power the M0 from a 3.7V LiPo and the Servo Wing from the 4xAA--again, the Servo is forgiving with respect to logic levels.  I probably should have had separate power sources in V01. One twist is that I'll need a DPST switch to turn on both power sources together.


Donkey V02 Circuit Working

Next steps are to construct and enclose the completed circuit and re-stuff the donkey.  Since the enclosure will be smaller, I'm going to try to get the batteries inside the donkey this time.
Fritzing Diagram of Circuit