I’m a little confused about powering and using the Little Soundie. The board will “work” with Vin of up to 5.5VDC, but the triggers only work with 3.3VDC? I’m making a permanent installation, don’t find a 3.3VDC wall wart available from SparkFun.
I’ve got a gazillion 5VDC wall warts in my stash, what would I need to do to use one of them and not blow out the triggers?
If there are no simple mods, and I need to buy a new unit, I think this power supply will work, can someone confirm?
What’s the point of making a board that “works” on 5.5VDC, but doesn’t actually work with 5.5VDC?
Why design it so we can’t use a USB charger as the power supply?
I can’t find Vin on the schematic. There’s VBUS, VHIGH, and VCC. I’m guessing VCC=Vin? I know electronica is slippery territory for a mechanical engineer, but it would help if labels on schematics more nearly matched labels on the board.
Thanks for the suggestion. That looks more complicated than I think I need. Even adding resistors for a voltage divider would add components and complexity. Since I’m still waiting on other parts for the project, I’ll just order a 3.3VDC wall wart.
I’m still curious why this will “work” with more than 3.3V, when the I/O is not 5V-tolerant. Any insights?
I’m still curious why this will “work” with more than 3.3V, when the I/O is not 5V-tolerant. Any insights?
Unfortunately that’s a design limitation of the VS1000D chip used on this board, you’d need to contact VLSI to see exactly why they designed it that way. I imagine the original intent of this chip was to be used in a portable audio player that could be connected to USB to transfer files but the rest of the circuitry was probably supposed to run at 3.3 volts.
It would have made more sense if Sparkfun brought out DVDD to a connector…
The data sheet specs the absolute max input voltage for the trigger inputs as 3.6 volts; going above this will damage the chip, and for safety I would keep it at 3.3V max. The data sheet shows the buttons tied to the trigger inputs being pulled up to 3.3V (DVDD aka IOVDD) with a 10k resistor. I would tap DVDD from the board with a wire and use that to feed the button pullups. U3 (the 8-pin SOIC chip) pins 7 or 8 are a convenient point to tap DVDD.
You should be able to power it from a usb power bank or charger if you use a power-only cable (one that only connects the red and black wires, and leaves white and green floating)
I have the Little Soundie running from the 5v pin of a Nano and have used logic level shifter (as has been mentioned) for the signaling, and it works fine. I even wired up the PB pin on the soundie so it powers up automatically.