I am new to this technology and I would like to develop a system that will provide a voltage output from a standard 4-wire load cell. Can I do that with your Qwiic Scale? If so, what other Sparkfun components will I need? Thank you.
Bob
Sure; check out the hookup section of its hookup guide and wire is similarly 
Hi Bob.
Sparkfun doesn’t carry a load cell amplifier that by itself can output an analog voltage. The best you could do with Sparkfun only parts would be to combine a digital output load cell amplifier, a micro controller board like an Arduino, and a DAC (digital to analog converter). Those three items along with some code you would need to write would convert a force on your load cell to an analog voltage.
If you’re looking for a board that just takes a load cell input and produces an analog voltage, Google can help you there. Aliexpress and ebay seem to have these pretty cheap, Mouser/Digi-key have modules that do this but they can get pricey. Google “analog output load cell amplifier” for some possibilities. 
What value of voltage? When powered appropriately, the load cell outputs a differential voltage in the mV range, which most instrumentation amplifier modules can handle.
Hi Bob (@Robert_Balmer ),
Welcome!
Your simplest set-up could be: a pair of AA batteries to power the load cell at about 3 volts; a precision digital multimeter to measure the small differential voltage produced by the cell.
What is your ultimate goal? What would you like to do with the voltage once you have it?
Best wishes,
Paul
Bob, I’ve got quite a lot of load cell experience and here’s how I’ve come to think of them:
Design a chunk of metal that flexes in a straight line, predicable manner within the load range. A simple bar of aluminum or material similarly stiff will work a little but it soon become apparent that curvature limits the load range and resolution. This gives rise to the weird dogbone shaped geometry you often see in the machining, they’re trying to get the load cell to bend as a parallelogram box. In the old days, they would install mechanical displacement/distance instruments, micrometers and dial gauges, to measure deflections of the metal and determine load. Proving rings and mechanical dynamometers are some of these still around.
With the metal chunk bending as needed, they glue electrically resistive pads (they resemble snips of foil) to the surfaces of the remaining chunk so that the electrical resistance changes with the flexing. There’s a lot of fine detail in the positioning and bonding but the pads, called strain gauges, are usually installed in pairs to form what we call a Wheatstone bridge. The design seeks to provide some off axis canceling and can help with temperature compensation.
This bridge gets powered by a pair of wires they often call excitation, I can’t remember ever seeing more than 15 volts and it’s usually 5-10 VDC, more is better. I’d rename that if I had my wish and simply call it load cell power supply or input or Vcc or any other conventional term. But the output of the load cell is usually called signal and it’s already a nice, linear voltage output. A good load cell properly mounted & loaded should have almost zero millivolts at zero Newtons load and a proportional output through it’s rated load capacity. The value of this output is given by the load cell’s rated output but 0.5-4 millivolts-per volt is typical.
Suppose you have this 10 kilogram load cell:
and measure 4.5 volts excitation and 1.87 millivolts signal. We see from the specsheet below that this is a 1 millivolt/volt cell but we’re only 41.6% of our maximum 4.5 millivolts at 10 kg so the load is around 4160 grams. This relationship gets better correlated through calibration when the load cell’s measured output is benchmarked against a known load.
You can do a lot of things with this output but, as suggested by @PaulZC, a battery and millivolt meter is all you need to begin taking some measurements. If you need a larger output swing than a few millivolts, a strain gauge amplifier or transmitter is a term to research. Strain gauges & bridges aren’t only used for weight and load cells, they use them in gas/air pressure transducers, torque measurements, seismic instrumentation, chemistry. Half the time, the elongation is the what’s being measured while the applied force is known. For example, if you were designing, I dunno, a better cue stick for pool or billiards, the same strain gauges as above glued along the surface can measure tiny displacement/elongation changes which can be otherwise really hard to measure during a fast movement like an opening break. Or golf clubs. Or piston rods or landing gear.
If what you really want is conventional weight or force, it’s hard to beat a commercial scale instrument. Even an ultra-economy one like QwiicScale is loads easier than taking it from the top.
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