To provide a large enough pulse to drive the ceramic transducer , you need a lot of energy, so they pump up the 5v with an inductor/transformer to provide a high voltage pulse. This is 60v or more…
The more Energy you produce the farther the pulse will travel….
Everything thing else on the board run at 3.3 to 5V.
Add a large Capacitor of 100 µF are so between the 5v and ground on the device, this may clean up your problem.. Some CPU modules just can’t supply enough current quick enough that’s needed when the pulse is triggered.
These are very inexpensive device, we’re luck to see them work at 1/2 the spec range.
@shabba
Hi, unfortunately I don't have time and patience for doing BOM's on all of my projects but in this case it's not very hard as the external component count is greatly reduced by using the NRF51822 RF SOC which is a PTR5518 module from Aliexpress. Other than that there is the Microchip touch sense controller - MTCH105 and the usual smd resistors(0603) and caps. Other than that you're not forced to use and solder the onboard dc-dc converter so you don't have to worry about those components - you just need to solder the 3V_EN jumper to use the Livolo 3V output coming from the main relays/power supply board.
