RPI is powered by USB from laptop
Transmitter is connected to Attiny85 being interfaced from RPI at 3v3
Receiver is connected to Arduino at 5v
If I have transmitter VCC connected to RPI 5v, data pin to Attiny85 running at 3.3v and all of them having same ground - all works fine, but obviously range is not great.
At this point same ground connects: transmitter, Attiny, RPI.
So I've tried using external power supply for transmitter.
I have power brick with DC output running at 12v
DC output positive goes to VCC, negative to common ground.
At this point same ground connects: transmitter, Attiny, RPI, power brick.
This doesn't work at all, receive nothing.
I've connected same power brick DC output to YwRobot DC in, positive 5v from board (actually pushing 8v) goes to VCC, negative from board goes to common ground.
At this point same ground connects: transmitter, Attiny, RPI, YwRobot.
This setup transmits data some times, still worse results than connecting VCC to RPI 5v.
Am I missing something? Does external power supply has to be something specific? I've thought as long as grounds are connected any power supply can be used on transmitter.
This 433MHz transmitter with PCB integrated antenna from my thermostat (powered by 2xAA) has no problem penetrating 3 walls and floor in my house. Sorry for my ignorance, but I need to achieve similar form factor and performance. 2.4GHz modules also require a lot of pins limiting what else can be done with Attiny85.