Let's Control It

I just found out that you could attach several sensors to the same SCA/SCL lines and got really happy and connected several sensors to try out. I now have LCD, BH1750, BMP180 and a HC-SR04 sensor connected to the same wemos. But how many sensors can I power directly from the wemos?

burton666 wrote:I just found out that you could attach several sensors to the same SCA/SCL lines and got really happy and connected several sensors to try out. I now have LCD, BH1750, BMP180 and a HC-SR04 sensor connected to the same wemos. But how many sensors can I power directly from the wemos?

this strongly depends on power supply and type of sensors. one limiting factor for 3,3v is the rt9013 power regulator at500mA, where the esp self takes about 350. usually the us-sensor should be powered by 5v straight from input and ping+echo connected to gpio by level shifter. so there most of the current comes straight from psu. pir must be powered from 5v too (doesnt need level shifter, ttl@3,3) relais boards with optocoppler can als use coil voltage @5v, servo should too. dont be stingy on the 5v power supply ... 1A is recommened minimum for many sensors, i had to go up to 1,5A for a node with 4relais, 4dallas temp, si7011,lh1750,mlx infrared temp sensor, servo and analog input.