This is the latest instalment of my adventure integrating the Ping Sounder.
When I send the “set_ping_enabled( disabled )” command, I can successfully read back the state with a get_ping_enabled() message. What’s more, holding it up to my ear I can hear it start and stop. (Yes critics, I know I can’t hear 115kHz, I’m probably struggling with 10kHz these days, but there is enough spectral leakage that you can hear it clicking away quite clearly)
I also see a small drop in the power consumption but not as much as I was hoping for. What should the consumption be for the disabled state?
I’ll give you the whole context. The hotel load on my host board is about 5mA. The Ping looks like it’s pulling around 100mA in disabled mode. I had intended to power down the Ping entirely, but the minimum voltage is spec’d at 4.5V. If my supply output voltage is above 4.3V I’m supposed to have a Schottky diode between the coil and the output which means that I can’t power down the supply completely (because the lower voltage input is passed straight through the coil and diode).
So either I need to run the Ping on 4.3V (and remove the diode and be able to shut it down completely) or I need to put the Ping into a deeper sleep somehow. Are either of these possible?
(The 4.3V is a bit of a soft limit too. I can also avoid the problem by band limiting the oscilloscope channel, but I’m sure that’s cheating 
)
Edit: Never mind the voltage limit option. If there is some kind of sleep option I’ll still take it, but the reduced voltage thing is ruled out in any case..