After developing several products focused on data acquisition, like the MRBW-RTS and a few currently in development like the MRB-DCCM (DCC Meter) and MRBW-DAQ (Data Acquisition node), we realized some of the ICs used in those designs would be useful on their own. To enable rapid development with these ICs, a series of ArduinoTM shields was created allowing you to easily implement a wide variety of data acquisition applications.
The ARD-LTC2499 puts together a high accuracy 24-bit ADC with a precision reference providing 8 differential input channels, 16 single-ended input channels, or any combination in between. The LTC2499 ADC is capable of directly converting a variety of inputs, including bridge transducers and even thermocouples and includes an internal temperature sensor that can be used for software-based cold-junction compensation. The input range is limited to 2.048V (50% of the reference voltage) by default, but this can be accommodated in most cases. The voltage reference is an LT6654 with 4.096V output voltage.
As with all our data acquisition Arduino shields, an EEPROM is also available for storing configuration coefficients or other data that travels with the shield (as opposed to inside the microcontroller on the Arduino board). The EEPROM also contains a 6-byte EUI-48TM-compatible globally unique ID to enable identification of specific boards or networked nodes.
A hardware reference can be found here describing the various jumpers and configuration options available on the board. A complete Arduino software library is also available. All communication with the board is via I2C.
The ARD-LTC1863 contains a 12-bit 200ksps ADC (LTC1863) with 8 single-ended inputs or 4 differential inputs. While the accuracy and resolution is not as good as the ARD-LTC2499, its speed is orders of magnitude better, making it suitable for many applications. The input range is 4.096V and an EEPROM for storing calibration data and providing a 6-byte EUI-48TM-compatible globally unique ID is also available.
Due to the data conversion speed, SPI is used to achieve the full data rate. Therefore, the ICSP header must be available to this shield. The EEPROM communicates via I2C.
The ARD-LTC2990 provides access to two LTC2990 Voltage, Current, and Temperature monitors. These parts let you measure single-ended voltage, differential voltage, or temperature using inexpensive and commonly available 2N3904 type transistors. The ARD-LTC2990 can measure up to 8 single-ended voltages, 4 differential voltages, 4 temperatures, or various combinations.
All communication is via I2C, including the onboard EEPROM for calibration coefficients and the 6-byte EUI-48TM-compatible globally unique ID. A hardware reference is available, as is a complete Arduino software library.
The links to the user guide info for the ARD-LTC1863 are missing.
Thanks – that’s an oversight on our part and I’ll get that fixed later today.
EDIT: It took a bit longer than expected because the original Ard186x library page apparently never was uploaded. However, I’ve got the hardware reference, library reference, and source library/example tarball all updated and uploaded now. Thanks for your patience!
I’m looking for a ADC 24 bits like ARD-LTC2499 but compatible with Arduino Due 3.3V,
Someone knows a shield like LTC2499 for arduino due?
The ARD-LTC2499 actually should work just fine with the Due, except that you can’t use the onboard I2C pull-up resistors (basically never jumper JP1). Those pull the I2C bus up to +5V, which will damage the inputs on the ARM processor. The built-in pullups on the I2C bus inside the part may be adequate for such a short, slow bus, or you may need to add a pull-up resistor (2k ohms or so) on each of SDA and SCL to +3.3V.
Is it possible to stack 2 or more of these boards to acquire more channels of data acquisition?
The LTC2499 on the ARD-LTC2499 has 8 possible I2C addresses (configured through JP4-JP6), so in theory you could use up to 8. The only gotcha on that one would be that the EEPROM only has four addresses, so you wouldn’t be able to use the EEPROM on each board.
The ARD-LTC1863/ARD-LTC1867 has two choices for the chip select line (D3 & D8), so assuming both of those lines are unused by other applications, you could stack two of them. If you really needed more, you could solder a jumper wire from the CS jumper over to other pins, but on most microcontrollers available in an Arduino-style form factor you’re going to struggle to get and process samples at the full rate from more than 1-2 boards.
The ARD-LTC2990 has been discontinued due to low sales.