TSL237 sensor on ESP8266 Wemos D1 Mini - esp8266

Question

I'm trying to read a TSL237 light sensor using my ESP8266 Wemos D1 Mini board. I have got code for an Arduino Uno from here (see copied below) and loaded it on my board. I first tried pin D0 on my board (GPIO 16) for the sensor data input, then pin D1 (GPIO5). In both cases I get the same useless output; I've copied one loop of this output below. Any ideas what I'm doing wrong?
CODE:
#define TSL237 2
volatile unsigned long pulse_cnt = 0;
void setup() {
attachInterrupt(0, add_pulse, RISING);
pinMode(TSL237, INPUT);
Serial.begin(9600);
}
void add_pulse(){
pulse_cnt++;
return;
}
unsigned long Frequency() {
pulse_cnt = 0;
delay(10000);// this delay controlls pulse_cnt read out. longer delay == higher number
// DO NOT change this delay; it will void calibration.
unsigned long frequency = pulse_cnt;
return (frequency);
pulse_cnt = 0;
}
void loop() {
unsigned long frequency = Frequency();
Serial.println(frequency);
delay(5000);
}
OUTPUT:
14:26:59.605 -> ets Jan 8 2013,rst cause:2, boot mode:(3,6)
14:26:59.605 ->
14:26:59.605 -> load 0x4010f000, len 3460, room 16
14:26:59.605 -> tail 4
14:26:59.605 -> chksum 0xcc
14:26:59.605 -> load 0x3fff20b8, len 40, room 4
14:26:59.605 -> tail 4
14:26:59.605 -> chksum 0xc9
14:26:59.605 -> csum 0xc9
14:26:59.605 -> v00041fe0
14:26:59.605 -> ~ld