Hi! I have a project where i need to read weight data from scale (KD SHIP-200 Lesak), so it's similar thing to this work http://www.avdweb.nl/arduino/hardware-interfacing/scale-interface.html . But my problem is, i don't have the same scale and there are no external ICs except memory module 24C02C with software of the scale itself. So i have no idea where to connect my Arduino UNO. There are some pins, VDD, VPP and RST leading directly into processor, but nothing else. Here is scale DPS http://www.imagehosting.cz/?v=1199225210.jpg . I can add some detailed pictures if you want to. More in detail, i need to turn off big motor (with relay of course) when weight goes to 25kg, but there should be a button to set weight to 50kg and big ass red LED to indicate overload or error in the system, but first of all i need to read those data from scale. Do you have any idea how to get this to work? Thank you!
There are pins named SCL and SDA, indicating an I2C connection, possibly accessible on CON2. Question is whether this bus is used for communication between the controller and the ADC, or whether it also allows access to the controller itself.
Can you identify what is the U2 chip (type, data sheet)? It could be an ADC with I2C bus, then there exists a minor chance to address it via I2C. It may have some analog output as well, easier to connect to an Arduino.
Detail: http://www.imagehosting.cz/?v=wp002927.jpg It's 24C02C 2K bit Serial Electrically Erasable PROM. Datasheet: http://ww1.microchip.com/downloads/en/DeviceDoc/21202J.pdf
Well... i'm pretty clueless now. So is there a way how to do it? Maybe connect arduino directly to sensor?
If your scale has USB port.
Zeppy: Well... i'm pretty clueless now. So is there a way how to do it? Maybe connect arduino directly to sensor?
Well as you found out these cheap scales use an all-in-one solution for their microprocessor that contains the amplifier, LCD controller, and switch inputs and there's little to no chance of getting any interface with it. This has been my experience as well.
Fortunately you can get an "HX711" module to interface with the load cell directly. Just a little bit of web searching will provide many examples.
Yay! Today is my lucky day, i have one HX711! But is there a chance of bad measuring or calibration with another device connected onto sensor?