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HX711Scale.ino
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/
HX711Scale.ino
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#include <SevSeg.h>
#include <HX711.h>
#include <avr/sleep.h>
#include <BTLE.h>
#include <RF24.h>
HX711 scale(7, 6); // parameter "gain" is ommited; the default value 128 is used by the library
SevSeg sevseg;
RF24 radio(9,10);
BTLE btle(&radio);
unsigned long long lastChangedTime;
float lastWeight;
struct nrf_weight_data {
int16_t service_uuid;
int16_t value;
};
nrf_weight_data payload;
void splash() {
for(byte i = 9; i > 0; i--) {
sevseg.setNumber(i*1111, i % 4);
unsigned long long nextFrame = millis() + 200;
while(nextFrame > millis()) {
sevseg.refreshDisplay();
}
}
}
void setup() {
byte digitPins[] = {14, 17, 18, 8};
byte segmentPins[] = {15, 19, 4, 21, 5, 16, 3, 20};
sevseg.begin(COMMON_ANODE, 4, digitPins, segmentPins);
sevseg.setBrightness(50);
scale.read();
btle.begin("Scale"); //8 chars max
payload.service_uuid = 0x181D; // org.bluetooth.service.weight_scale
scale.set_scale(27477.f); // this value is obtained by calibrating the scale with known weights; see the README for details
splash();
scale.tare(); // reset the scale to 0
// Serial.begin(9600);
}
void powerDownCpu() {
ADCSRA &= ~_BV(ADEN); // ADC off
set_sleep_mode(SLEEP_MODE_PWR_DOWN);
sleep_enable();
sleep_cpu();
}
inline float ABS(float a) {
return a >=0 ? a : -a;
}
void loop() {
float kg = scale.get_units(1);
// Serial.println(kg);
sevseg.setNumber(kg, 1);
payload.value = kg/0.005;
for (byte i=0; i<3; i++) {
unsigned long long nextAdvertisement = millis() + 100;
while(nextAdvertisement > millis()) {
sevseg.refreshDisplay();
}
btle.advertise(0x16, &payload, sizeof(payload));
btle.hopChannel();
}
if (ABS(kg-lastWeight)>1.f) {
lastWeight = kg;
lastChangedTime = millis();
}
if (lastChangedTime + 15000 < millis()) {
scale.power_down();
radio.powerDown();
powerDownCpu();
}
}