Where can I find/Why Can't I find a basic low cost voltage data logger?

Community Chit Chat
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I have spent a lot of time searching for a low cost data logger but haven’t been able to find anything. All I’m looking for is something that measures a voltage over time and writes that to memory (SD card or other) to download later. Example application would be measuring the voltage coming from a solar cell over the course of a day. I had something like this in College 16 years ago, but can’t find any out there today. There are data loggers out there but they are expensive (~$200) and high end, I am just looking for something cheaper( <$40). Sparkfun has OpenLog but that is a serial data logger, is there something equivalent that just logs voltage over time? In fact OpenLog has all the hardware available to do this, it would just require a PCB change to provide access to the ATMega328 ADC Pins, so I know there’s not a hardware limitation to building a device like this. Thanks

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While the OpenLog may need some alterations, you should be able to alter the software in the SparkX OpenLog Artemis to configure the RX and TX pins to ADC pins.

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The OpenLog Artemis (link: https://www.sparkfun.com/products/15846) actually has 4 analog input pins broken out on the PCB already. Two of those, as Brandon mentioned, can also be used as an auxiliary UART. But you should be able to use pins 11 and 32 directly without taking up your extra UART capability. (According to the schematic, link here: https://cdn.sparkfun.com/assets/c/6/c/a … ematic.pdf)

I believe that those pins can be configured to log analog voltage without even changing any firmware - just connect to the OpenLog through a serial monitor and follow the on-screen menus to configure it. Enjoy!

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One of my “pet peeves” is that so few SBCs (Single Board Computers) include a true “Real Time Clock” built-in…

Anyway, I’d suggest that you take a gander at the Teensy line – for instance the [Teensy 3.5 (with headers). You can add a separate battery to keep the RTC going, and it has 25 analog inputs as well as a built-in Micro SD slot.

Not bad for less than $30! (It may take a bit more programming than the previously mentioned Artemis, though I’d be surprised if there wasn’t an existing “sketch” out there that will do it.)](Teensy 3.5 (Headers) - DEV-14056 - SparkFun Electronics)