Posts: 3
Registered: ‎10-02-2015

si1145 UV and Visibility range problem

Hello there,

I'm using Si1145 for Visibility, UV and IR measurements.

for UV I've set the coefficient as follow

write8(SI1145_REG_UCOEFF0, 0x7B); 
write8(SI1145_REG_UCOEFF1, 0x6B);
write8(SI1145_REG_UCOEFF2, 0x01);
write8(SI1145_REG_UCOEFF3, 0x00);


and enable EN_UV, EN_IR, and EN_VIS in CHLIST, and I'm getting all three parameters in terminal tool

but the problem is from 1-2 feet close to my office window, sensors shows about 11 UV index in morning  and if i remove condition if(UV>11), then it reflects around 23-30 UV index!!!

Before measuring sensor data I've set VIS_Range and IR_Range parameters in PARAM_ALSVISADCMISC and PARAM_ALSVISADCMISC


Along with UV there is one more problem with Visibility

in my code I've set ALS_VIS_GAIN to 7 for maximum range and able to read data from direct sunlight

but the problem is, it shows -1 readings after 15000lx!!


where as it's not happening in case of your sensor puck product demo

Here I've attache my sensors reading file and It's program file

can any on help me 

I really appreciate all precious comments and suggestions! 


Posts: 18
Registered: ‎03-21-2014

Re: si1145 UV and Visibility range problem

Hi, thanks for entering this request also in our support portal.  Your case seems somewhat specific to your conditions, so we will reply in that system.