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SparkFun OpenScale Simple-to-use Open Source Solution for Measuring Weight and Temperature Includes HX711 24-bit ADC for weigh Scales TMP102 FT231 with Mini USB, for USB to Serial Connection

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$34.50

$ 17 .99 $17.99

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About this item

  • SparkFun OpenScale: Simple-to-use, open source solution for measuring weight and temperature while reading multiple types of load cells
  • The OpenScale was designed for projects and applications where the load was static and/or or where constant readings are needed without user intervention
  • Features: Operating Voltage: 5V, Operating Ampage: 80-100mA, Power Cycling above 500ms, Selectable 10SPS or 80SPS Output Data Rate, Local & External Temperature Sensors, Fixed & Adjustable Gain
  • ATmega328P microcontroller: Used to address all of your communication and data needs transfer your data to a serial terminal or to a data logger such as the OpenLog, an FT231 with mini USB
  • For a USB to serial connection: the HX711, a 24-bit ADC for weigh scales; and the TMP102, for recording the ambient temperature of your system-
  • The OpenScale communicates at a TTL level of 9,600bps 8-N-1 by default and possesses a baud rate configurable from 1,200bps to 1,000,000bps.


The SparkFun OpenScale is a simple-to-use, open source solution for measuring weight and temperature. It has the ability to read multiple types of load cells and offers a simple-to-use serial menu to configure calibration value, sample rate, time stamp and units of precision.

Simply attach a four-wire or five-wire load cell of any capacity, plug the OpenScale into a USB port, open a terminal window at 9,600bps, and you’ll immediately see mass readings. The SparkFun OpenScale will enable you to turn a load cell or four load sensors in a Wheatstone bridge configuration into the DIY weigh scale for your application.

The OpenScale was designed for projects and applications where the load was static (like the beehive in front of SparkFun HQ) or where constant readings are needed without user intervention (for example, on a conveyor belt system). A load cell with an equipped OpenScale can remain in place for months without needing user interaction!

On board the SparkFun OpenScale is the ATmega328P microcontroller, for addressing your communications needs and transferring your data to a serial terminal or to a data logger such as the OpenLog, an FT231 with mini USB, for USB to serial connection; the HX711, a 24-bit ADC for weigh scales; and the TMP102, for recording the ambient temperature of your system. The OpenScale communicates at a TTL level of 9,600bps 8-N-1 by default and possesses a baud rate configurable from 1,200bps to 1,000,000bps.


_Customer
Reviewed in the United States on January 16, 2023
As a load cell interface for a computer, this board works fairly well - when you finally figure out how to use it correctly! Spark Fun has put a number of different features on this board - not all of which you may need or use - but which makes it flexible and useful for a number of applications. The firmware has 13 different options or modes which can be set using a terminal program on Windows. That is both the good news and the bad news. For example, if you happen to mis-type the number when changing the serial port baud rate (yes, I did this), the board will use that rate even if it is not one of the standard rates. Once the terminal screen is gone, and if you don't know what that mis-typed number happens to be, you've just "bricked" communications. Fortunately there is a hardware reset feature, but you have to manually short two contacts and then reconnect the board - the "reset" button installed on the board doesn't do this (not really sure what it does, but it has a great tactile feedback click!).Anyway, for my application I was finally able to get the board reading my load cell and it is working well now. I cut the jumper to increase the sampling rate to 80 Hz and I get nice stable readings or reports (with one exception - see below!) at 40 Hz (note: the REPORT rate, or message rate to the computer will always be lower than the sampling rate due to internal overhead in processing and serializing analog samples).The "exception" that I mentioned (Spark Fun people, NOTE THIS PLEASE!), is that about once in every five hundred (or so) reports, there will be an erroneous force value that appears as a "spike" in your data. This is NOT a single character error (dropout or bad character), but an actual incorrect load cell value that is significantly different than the "true" values in the data stream. I did see a mention of this in a Spark Fun forum from several years ago, and it was supposedly going to be fixed in an ensuing firmware update, but as of the current version 1.2 it is still there. Because these spikes are easily detected and infrequent, I found a simple way to remove them in my software, but if you are using this without custom software then this may be a problem for you.For my use, I would give the board 4 stars, but because of the glitch and the learning curve to use the board well, it only gets three stars for general purpose use. If Spark Fun would update the firmware to remove the data spikes, and provide a bit better documentation, this could be a five star product.
MC BEEFUS
Reviewed in the United States on August 18, 2019
I'm on my second board, second set of load cells, multiple wiring configurations. I'm giving up.