Hi all,
I am wondering if anyone has tried to integrate two different sensors at one Bristlemouth node site on a Sofar Spotter buoy? Or is this a non-starter with the current configuration?
We are interested in comparing readings from two different instruments deployed at the same exact same depth and so we thought the most streamlined way of doing that would be to use the same node.
Thanks in advance,
Katey Lesneski
Florida Keys National Marine Sanctuary
Hello Katey,
This is definitely possible to do, but you might run into issues if the two instruments use the same communication protocol. For example, RS232 is a point to point communication protocol and if both sensors utilize this protocol, then it would not be possible with a single development kit.
Do you have the name of the two instruments that you are attempting to utilize and/or the communication protocol required?
Hi Katey,
Are you talking about plugging multiple sensors into a single dev kit mote (which is what Matt’s talking about), or do you mean multiple dev kits at the same site along the smart mooring cable so that they’re at the same depth in the water column?
If you mean the latter, I know we recently put an RBR alongside a development device mounted side-by-side on one fixture. We just put this in the water for a brief deployment to learn about the development device.
1 Like
Thanks so much Matt and Zachary for your replies!
We want to explore the possibility of plugging multiple sensors into a single dev kit node.
One instrument is the Seabird SBE37SI MicroCAT (appears to utilize RS-232) and the other is a device that @Anuscheh is developing at UW - hoping she can help fill in some details!
Thanks @katey.lesneski! We currently have all data (from pressure, temperature and salinity) routed through an Arduino, which we ping from the computer. @kucewicz can you help with the details here? We have integrated the sensor with the dev node.
As Matt was saying, using a serial line (UART, RS-232, RS-485) the dev kit mote can only talk to one sensor at a time.
A bus like SPI or I2C is designed to handle communications with multiple devices, and the mote has both of these available.
Since the Seabird SBE 37 SI can only speak serial, then you’ll have to talk to the other sensors on SPI or I2C. Depending on what interfaces the other sensors have available, you could do either of these options:
- If the UW pressure, temperature, salinity device can speak SPI or I2C, then you can connect it to the Bristlemouth dev kit using that bus. In this case you don’t need the Arduino.
- You could connect the dev kit to the Arduino over SPI or I2C. The main downside is that you need to maintain both firmware applications — one on the mote and one on the Arduino — as well as designing a protocol for them to talk to each other.
Hope that helps! Let us know if you have more questions.
Thanks for the info and sorry for the late reply on my end as I have been on work travel! @kucewicz do you have any thoughts given these details?
Hi all,
I’m working with Anuscheh, connecting our Arduino-based CTD to the Dev Kit.
So far, I have tested connecting Arduino to Dev Kit by using the serial_bridge guide.
We want to connect one RS232 sensor in the Dev Kit side if possible.
Would it be possible to connect the Arduino to Dev Kit by I2C, and RS232 sensor at the same time?
If there is an example firmware, it will be highly appreciated.
1 Like
Hi @cwl20!
What you are suggesting is totally possible, however, there are no examples of it right now. So you will need to write a lot of code for the Devkit to be able to talk to an Arduino via I2C.
I’ve thought about another approach that may be a tad more simple to implement.
The devkit actually has two USART peripherals. One is the LPUART and this is referred to as the PAYLOAD_UART in the example code. There is also the USART3 peripheral which is currently not being used.
You could in theory (this is untested) leave the LPUART/PAYLOAD_UART connected to the Arduino and then use jumper wires to go from the USART3 pins to the RS232 transciever that is on the devkit to talk to your sensor. You would need to implement a lot of the USART3 code, however, you could essentially replicate the PAYLOAD_UART code, but use USART3 as the serial handle you are using. (refer to payload_uart.h/.cpp). Once you have a similar system set up for USART3 you could follow the RS232 integration guide.
(Or you could use the PAYLOAD_UART for talking to the RS232 and hook up the Arduino to USART3, either approach would involve about the same amount of work.)
Here are some photos of where to connect the jumper wires:
Either approach should work whether you use I2C or USART3!
Hope this helps! Let us know if you have any follow on questions!
2 Likes
Wow, thank you for sharing this!
It looks like a really smart approach, but a bit overwhelming to me since I’m more comfortable working on the Arduino side.
I think I’ll try to keep everything within the Arduino or maybe just add a bridge Arduino for now.
Thanks again!
2 Likes
Keep us informed as to how that works! We’d love to follow along.
Z