Fire detection using the scattered light principle with a staggered activation of a further LED unit for radiating in further light pulses with different wavelengths and scattered light angles

Various embodiments may include a method for fire detection comprising: radiating light at a first wavelength into a scattered light volume and measuring a radiation intensity generated by forward scattering; radiating light at a second wavelength and measuring a second scattered radiation intensity generated by forward scattering; determining a first quotient from the scattered radiation intensities and comparing it to a first and second value; and if the first quotient lies between the first and the second value; radiating pulses at the second wavelength into and measuring a third intensity generated by backward scattering; determining a second quotient from the first and third scattered radiation intensity and comparing the second quotient with a third value; and generating a fire alarm if the second quotient exceeds the third comparison value.