I have an idea for little project where I want to log weight changes (standalone) on a bee hive, preferably low-cost.
Now there's a lot of cheap temperature loggers on the market, for example this one: Temperature Data Logger on ebay.
Is it possible to connect a load cell to this or any other generic temperature logger, provided that I apply the right amplification to get the load cell to work in the same output range as the temperature sensor? Or is a temperature sensor output radically different from a load cell output? I have no problem with using a formula to convert the temperature values to kg values.
Best Answer
Almost certainly the output from a load cell is a Wheatstone bridge whereas the output from a temperature sensor is typically a single-ended two-wire configuration that offers a resistance change with temperature or maybe a constant current output like the AD590.
This likely means that the load cell would need to be buffered with an instrumentation amplifier followed by a voltage to current generator if you are lucky to find that the temperature logger you have uses a device similar to an AD590 then you are OK - it can be done.
However, if your temperature data logger expects the input sensor to be a thermocouple of platinum resistance type gauge then you won't be successful.
Added to this, you need to provide an excitation voltage to a load cell - it is a four wire device; two wires are excitation supply and two wires are its output.