FabLab Project - Are the Fish Biting?


I run a FabLab and we are planning to hold a class called Raspberry Pi and Cayenne - the perfect recipe for IoT. We need to come up with a good project that students can complete in a few days. Fly fishing is really big around here, perhaps we could develop a project that notifies you on your smartphone if the fish are biting :slight_smile: Hhhmmmm…what kind of sensor integration would we need for that?

Maybe we should start with something easier. I have connected up a BMP180 and a LED to the Pi. Configured the temp and pressure aspects of the sensor and have them displaying properly. I added the Light Switch and set up a trigger so that if the temperature exceeded 80deg F the light would turn on. Added a second trigger to turn the light off when the temp dropped below 80deg F. All of that is working good. Hooray!

I understand the BMP180 also has an altitude sensor? But I don’t see that as an option when I go to configure it.
Also, the pressure is reporting in pascals. Can we get the units reporting in/Hg?


Hi Matt,

Good to see you here in the Cayenne Community. I think the altitude is just used as an input to determine the pressure, but it’s not an actual sensor on the BMP180.

The fly fishing project sounds cool… perhaps we start with goldfish though :slightly_smiling: @Ian seems to be the current community expert on aquatic Pi projects at the moment. TSL2561, BMP180, DS18B20 on a Zero

We will allow for users to change units, but there it is not possible right now unfortunately.



@matt.grimes, welcome to the fray!

I have no idea what parameters make for good fly fishing, but I do know that the combination of a BMP180 and a DS18B20 are an excellent combo that could be implemented into several projects very easily. I currently have this combination is service on 2 separate RPi’s reporting to Cayenne; one with the 18B20 outside measuring ambient temperature (with SMS and email triggers) and the BMP180 in the basement (with a turn on a LED trigger to a third RPi). The other one has the 18B20 in my fish tank monitoring the water temperature and the BMP180 catching the upstairs temperature. Both of the sensors are supported by Cayenne and not very expensive.

One of the nice things about the 18B20 is its one-wire protocol allows for fairly long cabling to the sensor. It seems I2C is much more sensitive to cable lengths.

The BMP180 only senses temperature and atmospheric pressure. If you know the current pressure you can determine altitude using MATH, oh the horror. Here is an excellent read on the correlation between altitude and pressure Parallax’s New Altimeter/Barometer Module.

Things get a little more complicated where I live because I’m at 4900’ (1500m) and things tend to be referenced from sea level.

The BMP180 is very sensitive, it can detect pressure changes with only a couple feet (1m) change in elevation, as is demonstrated here by Paul McWhorter.

Sounds like a great project, please let me know if I can help,



@Ian , Thanks for the links to the articles. They will be extremely helpful. My interest in altitude has to do with a different project that we are going start working on soon. It is a near-space photography project similar to the one detailed in Make Magazine - Article and we will need to determine the altitude of the balloon as high as 90,000’ (27,000m). Math is ok,we can deal with that, my colleague has a PhD in Physics!

@Benny, yeah goldfish might be a better place to start. Particularly as I need to involve some youngsters in the project.


Please visit my friends at Edge of Space Sciences as they have been doing high altitude balloon launches since the early '90’s. They are well over 200 successful launches now. I was a part of the group when the launches numbered in the teens. I worked on the tracking a recovery team when the primary means of location was radio direction finding by ground stations, this was before GPS, APRS, mobile internet, digital cameras, although I do remember having some payloads with LORAN-C on board, leading edge technology for the time.



I would definitely like to connect with them. Do you have anyone specific in mind? Having a mentor would be ideal since we’ve never done this before. You can email me directly at matt.grimes@umontana.edu


These sensors would likely be useful as well.

Rain, Lightning