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DS18B20 are small true temperature sensors. You can find them easily on ebay for a couple of $.

Default settings:

By default the bugOne use PD5 for this sensors. You can tweak this in devices/onewire.h

#define OW_PIN  PD5
#define OW_IN   PIND
#define OW_OUT  PORTD
#define OW_DDR  DDRD

The default setting for power supply is parasite. Just power the device through a 4.7k pull-up on pin DQ. You can change this in devices/ds18x20.c

int8_t ds18x20_read(struct packet_t *packet) {
    uint16_t temperature;
    uart_putstr_P(PSTR("ds18x20 read\r\n"));
    DS18X20_read_decicelsius_single(DS18B20_FAMILY_CODE, &temperature);

    return set_data_int16(packet, temperature);


  • If you receive dumb values from a sensor, usually mean the bugOne can find this sensor. This can be a wiring error, or a wrong power mode (check parasite mode).
  • If you receive 850 (85.0°), usually mean the bugOne found the sensor but was unable to read the value. This usually occurs with bad connexion, for example on a breadboard. I spent some time on this error, but it's always a hardware failure not a software bug.
devices/ds18b20.txt · Last modified: 2014/12/24 16:47 by jkx
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