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Simple Arduino voltmeter for starters

Building a DC voltmeter with Arduino is really a matter of seconds. But for those who is learning microcontrollers and want to build something working this is a great project. Here you have to deal with several areas of electronics. First of all reading analog signal. As voltage cones in directly to analog pin, the range is limited to 5V. Next thing is driving three 7-segment Led display. It is common anode type where anodes of each digit is driven with transistor key. Program code is also easy to follow and easy to modify if needed. Even if it looks simple project, it can be useful in many areas like checking battery voltage, or probing other things where voltage ranges from 0 to 5V. Continue reading

Monitoring four voltages with Arduino

This is really simple project when speaking of measuring voltage with Arduino. This is only a matter of reading analog input value. 1.8” TFT display makes it look more solid and useful in many areas. Johnag build four channel DC voltage meter project where he is able to monitor voltages up to 55V DC. We all know that arduino is capable to measure voltages from 0 to 5V, but with use of resistor divider this range can be expanded with adequate resolution loss. Since it is measuring higher voltages that Arduino would handle there are protection diodes used on analog inputs. To make readings reliable, it requires some initial calibration with multimeter or known voltage reference. Author indicates one constraint. It cannot measure voltages across any component – only from ground reference. But this doesn’t make it poor device as there are many applications where this problem doesn’t apply. Continue reading

Arduino as multichannel voltage meter

Arduino voltmeter

Practically there is nothing special about measuring voltages with Arduino. Simple analogread() command already takes care of getting values and converting them to voltage using coefficient. Anyway for some starters this might be quite educational to build something similar. This voltage meter uses four Arduino analog inputs. Each channel is equipped with resistor voltage dividers that scale down voltage 10 times. So practically 5V powered Arduino can be used to measure voltages up to 50V. Voltage values are displayed on standard LCD which already has library for fast use. If you need to tune the measured values there are calibration constants available in sketch where you can individually select to make Arduino voltmeter pretty accurate. Continue reading