#define TWI_ACK TWCR = (1<<TWINT) | (1<<TWEA) | (1<<TWEN) | (1<<TWIE)
#define TWI_NAK TWCR = (1<<TWINT) | (1<<TWEN) | (1<<TWIE)
#define TWI_RESET TWCR = (1<<TWINT) | (1<<TWEA) | (1<<TWSTO) | (1<<TWEN) | (1<<TWIE);
#define TWI_ACK TWCR = (1<<TWINT) | (1<<TWEA) | (1<<TWEN) | (1<<TWIE)
#define TWI_NAK TWCR = (1<<TWINT) | (1<<TWEN) | (1<<TWIE)
#define TWI_RESET TWCR = (1<<TWINT) | (1<<TWEA) | (1<<TWSTO) | (1<<TWEN) | (1<<TWIE);
static volatile uint8_t start_dist_fwd2=0;
static volatile uint8_t start_dist_bwd=0;
static volatile uint16_t voltage=0;
static volatile uint8_t start_dist_fwd2=0;
static volatile uint8_t start_dist_bwd=0;
static volatile uint16_t voltage=0;