Abstract: These days, environmental pollution by heavy metal is a serious public concern. A low-cost and an environmental-friendly equipment is rigorously needed to measure heavy metal existed. In this work, we developed a low-cost spectrophotometer to measure heavy metal absorbance by using TCS3200 sensor. The sensor is used to sense the color gradation from dissolved heavy metal. System developed is highly sensitive, cost-effective, user friendly, IoT-enabled and connected to smartphone-based Android operating system. Heavy metal materials that used in this work are FeCl3, NiSO4, and CuSO4. We found that the increasing of the heavy metals concentration affects to the reduction of the sensor frequency. Equipment system developed shows good performance in measurement of heavy metal concentration. For FeCl3 material, the average accuracy is found to be 95.5% and the precision is 98.7%. For NiSO4, the average accuracy is 96% and precision is 98.3%. For CuSO4 material, the average accuracy is 99.3% and precision is 99.8%. Total amount of production cost less than 20$. Detail on the research is described in this paper.