Have an original homebrew project using the WTV020-SD-16P. The WTV020 3.3V power is provided from an Arduino UNO. A PIR motion sensor is wired to a TTL NAND gate chip, and interlocked with the WTV020 pin 15 "BUSY" signal. If the PIR senses movement and the WTV020 is not running, a TTL NAND gate output wired to WTV020 pin 13 goes to zero, triggering the WTV020 to play the next sound file. The BUSY signal is also wired to an Arduino input to count & sequence LEDS & animation action. http://www.youtube.com/watch?v=mVS0TIDwLdM.
A second prototype of this project is in process, using an Arduino 2560Mega instead of the UNO. Eliminated the TTL HW, direct wire IO to control the WTV020. Have tried 2 different WTV020 modules, both cause the Mega to overheat the 3.3V power supply chip. A cheap Buck switching power supply is then used to provide 3.3V (from a 5V bulk supply). The Arduino is fed 12V from a separate supply, COM grounded ( ground prong of 115VAC plug). There is a 5v 5a bulk supply also with COM tied to ground. All COMs are ohm checked to ground. There was a buzz getting thru the 15W audio amp, adding a series ferrite core choke from the 3.3V supply to the WTV020 squashed the noise. ( Later I also added a 100 mike cap across the 3.3 V supply, and 6 ohm load to ensure continuous current on the 3.3V supply )
Now, the problem: Both WTV020s have somewhat misbehaved. The first WTV020 would lock up if the NEXT pin was grounded while it played. A reset by cycling power or grounding pin 1 would allow it to restart. Still used it to continue working on the project until a replacement arrived. Once the WTV020 was triggered by grounding pin13, it would not stop at the end of the sound file, it would continue onto the next sound file.
A replacement WTV020 arrived, seemed OK when first tested. Now it does the same thing, once triggered after powerup, it keeps running. Tried using optocouplers ( a 4N35 OMRON 61B1 solid state relay) and then a relay contact to trigger the WTV020, no change. All the WTV020 input pins read the same Vcc 3.3V open circuit. usually when I grounded the pin 13 to trigger , a 1k resistor was in series just in case.
Wondering if I just have bad luck, or if I am missing something in troubleshooting ( been testing things for 2 weeks ). Now waiting for the next WTV020 ordered ( 3rd one) to get here. The first protoype has a 5V supply from TTL triggering the WTV020 with no trouble. This protoype has no TTL interface, wondering what else could be different between UNO and MEGA, the interface is minimal anyway.......any ideas or experiences ?