Multichannel Professional Data Logger on Raspberry Pi - Part 2

See the Part 1 for the overall description and Part 3 for the software implementation.

Hardware

The most interesting part to deal was the hardware. Below you can see an old prototype board, which includes a Raspberry Pi, two custom boards for ADC, sensor connectors and voltage dividers. In the middle - a small board to supply a power. It has real-time input voltage monitoring: on 7.5V - the Data Logger start making warning sounds, on 7.0 V - automatic shutdown. Two power supplies: AC-DC external, and internal pack batteries. Also the embedded ORing controller makes a smooth transition between battery and external power supply.

The boards has been designed and implemented by Boris Shogan, my old friend and awesome Electronics Engineer. It took a noticeable amount of collaborative work in our spare time and midnight oil burnt to make this happen. But it was a plenty of fun.

Since we need 16 ports total, the natural choice was to take two MCP3008 8-Channel 10-Bit ADC with SPI interface, and have it on two standalone boards (a compact 16-port single board which hosts both ADC is also available).

Originally we had it working on Raspberry Pi Model B (512 MB RAM), and later used the Model B+. We did not tried the Raspberry Pi 2, it was released just a few days ago.

Below is the IV-board for Currency and Voltage. The low-side external Shunt or Sense resistors are plugged to the blue connectors:

Currently this types of Shunt and Sense resistors are supported by default, other types can be easily added:

• Shunt 500A 50mV
• Shunt 300A 50mV
• Shunt 100A 100mV
• Shunt 100A 50mV
• Shunt 10A 100mV
• Shunt 2A 100mV
• Sense R=0.1 15A
• Sense R=0.1 20A
• Sense R=0.25 14A

Below is T-board for Temperature measurements. The sensor is J-type thermocouples (also not shown, can be plugged to the connectors on the bottom).

See below the image of the complete product in the box. We have been given the enclosure, and this Customer asked us to make a table-top version, so here it is. Meantime we are working on a smaller "portable" version. Stay tuned.

Feel free to get back to me if you would like to get more details about the system, get a copy of software, or customized version for your needs. You can also purchase the assembled ADC boards or DIY kits.