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I made my own USB DOCTOR!!

A lot of power meters available in market which delicately made to work with 5volt charger power. The maximum ratings of my commercial one is 7v at 2amps. Now I want to use this USB charger doctor with my fast charger but it is not compatible at all. That’s why designing of this DIY charger came into my mind. My fast charging adaptor goes upto a rating of 80watts. A voltage divider network is used to measure the voltage upto 20volts with a current rating of 5ampere. I want to display the real time readings of this USB doctor on a small display and I choose atmega328p as a microcontroller and SSD 1306 128x32 OLED display of it.

Voltage readings are direct measurable with 10-bit internal ADC of the microcontroller which gives a resolution of 15mV and I used dedicated ACS712 for the current measurements. Which is based on hall effect and using this current readings can be easily converted into respected voltages and then any variation in current produce variation in voltage (For 5v ACS take 2.5v as a reference). To know more about ACS712 and it’s different variants check the data sheet from here.

- Arduino nano or Atmega328p
- ACS712 5A version
- SSD1306 OLED 128x32 display
- 10k, 4.7k resistors
- 100nf and 10nf ceramic capacitors
- Ams1117 5v
- USB Type A connectors
- 16MHz crystal oscillator
- Custom PCB

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