I'm trying to build a trash bin that can weigh papers and send those results in a PC/laptop every 5 minutes using arduino and sensors, particularly load cells(I'm familiar with arduino and IR sensors but this is my first time to encounter other types such as this so please bear with me). So basically, my project is made up of two parts: the data transmission and data gathering. I'm already done with the transmission and can send sample data(strings) to this statistical software tool:
using this wifi shield(can't afford the arduino one :( ): http://www.dfrobot.com/wiki/index.php/WIFI_Shield_V3_RPSMA_SKU:TEL0079.
now about the weighing part, i found out the simplest logic for it:
load cell => amplifier => ADC
so i bought a 3 kg and 40 kg load cell(at the bottom): http://www.e-gizmo.com/PRODUCT/ELECTRO/SENSOR.HTM
and an amplifier(i bought an already-built amp to save some time): http://www.e-gizmo.com/KIT/sensoramp.html
plus i also bought a controller w/ display for the sensor(to see actual values from the load cell): http://www.e-gizmo.com/KIT/weight%20Sensor.html
those product's documents are also in the links(left panel).
Now i connected the load cell in the amp based on its manual(I'll also call their technical support to verify if I connected it right) then fed that single output from the amp into the Arduino(Uno r3) analog pin(A0) and i got random numbers from 0 - 1023 in the serial monitor. This is the confusing part, i know this figures are amplified voltages(?) but my question is, how can I convert these into weights particularly into grams? Seems like these numbers are way too random to even be of use and plus is it normal to see fluctuating readings even if there's no load? . and how can i verify that the load cell's output with a load is different from without a load just from looking at the readings? or is it impossible?
Sorry for those annoying questions but i really really really need every help i can get. Also, sorry for posting too many links and step by step info about our project(it seems like i really need to do it to explain more efficiently). I would really be grateful to anyone who can help me out with this. Thanks in advance! :)