I have built a data logger that monitors the start-up star of my analog water meter and calculates the current water consumption. It works great, but now it's hard for me to decide how to get the data out of the basement where the water meter is mounted. Since there is no electricity in the basement, I have to lay a cable anyway.
Option a) Solar power it with a short cable and use wifi for the data transfer
Option b) Lay a 20 m long three- or four-core power and data cable
I prefer option b), but now I wonder if I will have problems if I simply extend the cables to the laser and the photodiode. It works in my test setup, but I don't quite trust it.
I pulse the laser diode at a rate of ~ 500 Hz, that means if I want to place the op-amp down in the cellar I would probably need at least a 4-core cable.
I basically see three options for the wired circuit:
- Simply extend the laser and photodiode wires (3-wires needed)
- Extend the op-amp output (4-wires needed)
- Add an additional microcontroller between the operational amplifier and the data logger for digital transmission of the signal. (3-wires needed)
Which route would you suggest and why?
PS: The data logger itself is currently an Arduino Nano with a DS3231 RTC, a microSD adapter and an OLED display. It logs every 1/6 revolution of the start-up star with millisecond resolution.