IoT Radio Receiver Test

433MHz/315MHz receiver test with the PlatformIO and Arduino framework

Boards:

Arduino UNO
Digispark ATTiny85 USB clone (LED on PB1)

Tested with non-default CPU frequencies 1, 8 and 16MHz. Default 16.5MHz feels to be the most stable due to being calibrated precisely by the micronucleus,while 1MHz has the most unstable receiving which probably could be fixed by adding antenna to the receiver module or otherwise by oscillator calibration.
Wemos D1 Mini (ESP8266)

Radio hardware:

Preferred: WL101-341 433MHz superheterodyne receiver and WL102-341 transmitter.
Cheapest: MX-RM-5V 433MHz ASK OOK super regenerative receiver and FS1000A transmitter
RFM83C superheterodyne receiver

Tips to improve transmit/receive distance:

Consider coil loaded antenna solution
FS1000A transmitter can use anything from 3.3V to 12V. Increasing voltage will increase transmit distance. If you are using voltage regulator, attach transmitter directly to the battery. Receivers needs 5V, it doesn't work on 3.3V unless otherwise is mentioned in specs
For WL101-341 and WL102-341 use bundled antennas (short for TX, long for RX).

Development

UART (Serial)

Digispark ATTiny85

Digistump dtiny core TinyDebugSerial overrides Serial and uses:

PB3 as TX for CPU frequencies <= 8MHz
PB2 as TX for other frequencies

See TinyDebugSerial.h for the details

Generic ATtiny85

SpenceKonde tiny core TinySoftwareSerial overrides Serial and uses:

AIN0 (PB0) as TX
AIN1 (PB1) as RX