This is an adapter board to connect an IMST iC880A-SPI LoRaWAN concentrator board to a Raspberry Pi (B+ / 2B / 3B / Zero). It also gives you some ways to enhance and monitor your gateway. Current version: v1.5.
Availability as of 2018-04-26: The boards with sensors are almost sold out again, we have parts for about 4 more of those boards left. (We also have parts for about 10-15 boards *without* sensors left, so feel free to order more of those.) We will manufacture those boards and add them to the shop soon. Meanwhile, we have started updating the design of the backplane, the next version (probably 2.0) will contain a fixed DC-DC converter with castellated edges for direct PCB mounting, as well as an updated temperature/humidity sensor (the brand new SHTC3 if it becomes available soon, the compatible SHTC1 otherwise as a temporary solution). It might take a few more weeks until everything is ready though.
Note: This board is sold as a development kit and not a finished product. It is hand-soldered with leaded solder and is not ROHS compliant. No certifications have been done, but every assembled board is tested by us before shipping, to ensure it works!
A note on shipping: Due to the thickness of an assembled board (>2cm), the shipping costs for fully assembled boards are higher than for the non fully assembled versions. You can calculate the shipping cost in the shopping cart.
Besides connecting the two boards, the PCB gives you the following additional features:
- Screw terminal for direct power input/output (5V)
- Screw terminal with on-board MP1584 step-down regulator (6.7-28V input, screw-adjustable output). Great to connect a 12V PoE-Adapter.
- Polyfuse and TVS diode to protect against voltage spikes
- Protection against accidentally reversed polarity
- Full access to Raspberry Pi GPIO header
- Pin header for serial communication (RX/TX)
- 2 pin headers with pull-ups for I²C based sensors (SDA/SCL/GND/3.3V/5V)
- Mounting holes for Raspberry Pi B+ / 2B / 3B / Zero
- Programmable button connected to GPIO (e.g. to shut down the Pi)
- Three programmable LEDs (Red/Yellow/Blue) connected to GPIO header
- MOSFET with flyback diode for connecting and regulating a 5V DC fan
- Open source hardware, full schematics provided!
Two nylon spacers are included. For the basic version all SMD parts are soldered, through hole parts (pin headers, screw terminals, regulator board) are not soldered. For the basic version you will need a multimeter to adjust the regulator board, in case you want to use it.
Optional: With Sensors (+10 CHF)
- Sensirion SHT21 temperature / humidity sensor made in Switzerland (accuracy: ±2%RH, ±0.3°C)
- Microchip MCP3425 16-bit ADC to monitor input voltage
Optional: Fully Assembled (+20 CHF)
- All boards come with the SMD parts already soldered, but with this option we’ll also solder all the pin headers, screw terminals and regulator board.
More details can be found here: https://github.com/dbrgn/ic880a-backplane
Note: In most cases, PCBs with sensors have red soldermask, and PCBs without sensors have blue soldermask. In case we run out of PCBs of the “right” color, we may als use the other color though.
- You can find the schematics here.
- The step-down regulator can be adjusted with a small screwdriver. If you buy the board pre-assembled, the regulator should be preconfigured to about 5.1-5.2V, but checking with a multimeter won’t hurt. Otherwise, adjust it to ~5.1V BEFORE SOLDERING IT TO THE BOARD and use a multimeter to verify the output voltage.
- If you bought the non-assembled version, you need to cut one of the 2×20 pin headers along markings to make the pins shorter, so that the two headers can be stacked.
- Here is a quick guide to using the SHT21 temperature/humidity sensor from the Raspberry Pi. And you can find a Collectd plugin specifically for the SHT21 on Github.
- Note: The Raspberry Pi has a hardware bug that prevents the sht21 kernel module from working with the latest kernel versions. If you experience these problems, try this userland driver that does not use I²C clock stretching. I submitted a patch that should fix this, you could also wait for it to hopefully be included in the kernel, or apply it yourself and rebuild the kernel module.
- The LEDs are connected to GPIO pins 36, 38 and 40 (BOARD numbering system). The button is connected to GPIO pin 32 (BOARD numbering system). You can find an example script here.
- In case you want to use the MCP3425 ADC to monitor the supply voltage: Here is an example script. You can find a Collectd plugin on Github. And here’s a brand new Rust driver.
- The LEDs and the button can only be used with 40-pin Raspberry Pis (model 2 and newer).
Feel free to contact us at firstname.lastname@example.org if you have any questions or any general feedback. We’re also happy about reviews, just click on the “Reviews” tab above!
Thanks for your order! With it, you are supporting the efforts of our hackerspace to provide the infrastructure for noncommercial technical projects and to teach electronics and programming to kids and other people that want to learn 🙂