The design and construction of the low-cost electric pulp tester

Abstract

The Electric Pulp Test (EPT) is one of the common method to evaluate the pulp vitality. Generally, the devices which provided in Thailand are imported and mostly expensive which limited the use of this technique. Then the objective of this research is to design and construct the low-cost electric pulp tester. The devices consisted of 3 parts; part 1 is the current source, part 2 is the current display and the last part is battery alarm part. The current source, which generated the maximum current at 90mA, and voltage comparator circuit were employed in our design. The plastic box of device was design by CATIA program and printed out by 3D-printer. To test the functional efficiency of circuits; generated current, current at each LEDs display and the effective voltage of the battery were detected. The results showed that the current source which we designed represented the accurate function as the percentage error was only 2.9% compared to the expecting current. In display part, The percentage error of the current at the green, orange and red LED were 2.8%, 1.6% and 0.3%, respectively. For the low battery alarm part, the LED display alarmed at the average voltage downed to 6.85 :f: 0.32 V. We concluded that the device we developed has effective functions and the price was 3000 baths. We expect to improve the better quality and purpose to produce the commercialized product of EPT afterward.