The Mini Pearl Logger is a powerful and inexpensive device for logging environmental data. It is based on an Arduino Pro Mini in combination with a real time clock and a microSD card reader. Combining these common electronic components allows logging data from multiple sensors for multiple months. Three different kits to build a Mini Pearl Logger are available at the [KAPtery](http://kaptery.com/products/data-and-control). The [Mini Pearl Logger Kit](http://kaptery.com/product/mini-pearl-logger-kit) is a minimal version that requires soldering and runs a sketch that puts the logger to sleep between logging events to conserve battery power. The [Mini Pearl Pro Logger Kit](http://kaptery.com/product/mini-pearl-pro-logger-kit) includes a TPL5110 low power timer which turns the logger off between logging events and maximizes battery life. The [Mini Pearl Snap Logger Kit](http://kaptery.com/product/mini-pearl-snap-logger-kit) includes a TPL5110 timer, a BMP280 sensor, an FTDI converter, and snaps together with no soldering required. [![FeatureTable.PNG](https://publiclab.org/system/images/photos/000/023/322/large/FeatureTable.PNG)](https://publiclab.org/system/images/photos/000/023/322/original/FeatureTable.PNG) All three kits include a DS3231 real-time clock which has an integrated temperature sensor and timekeeping is automatically corrected for temperature. Data from this sensor can be read and logged. The Mini Pearl Snap Logger Kit includes an additional external sensor for barometric pressure and temperature, and many other sensors (including I²C, 1 Wire, and Grove) can be connected to any Mini Pearl Logger. [![miniGo_20180107-2413.JPG](https://publiclab.org/system/images/photos/000/023/319/medium/miniGo_20180107-2413.JPG)](https://publiclab.org/system/images/photos/000/023/319/original/miniGo_20180107-2413.JPG) _Above: The parts included in the Mini Pearl Snap Logger Kit. Everything needed to log temperature and barometric pressure for many months (except three AA batteries) is included. An FTDI converter (red) for connecting the logger to your computer is also included._ This logger is based on Ed Mallon's [Cave Pearl Logger](https://edwardmallon.wordpress.com/2015/10/24/diy-arduino-logger-build-instructions-part-1/) which uses a similar combination of components. Ed has done extensive testing to extend the field longevity to more than a year. [![miniGo_20180107-2448.JPG](https://publiclab.org/system/images/photos/000/023/318/medium/miniGo_20180107-2448.JPG)](https://publiclab.org/system/images/photos/000/023/318/original/miniGo_20180107-2448.JPG) _Above: An assembled Mini Pearl Snap Logger. The six components are connected with DuPont wires which slide onto header pins on the PCBs. It takes about 15 minutes to get one finished and logging data._ ###Parts Primary components: - **Arduino Pro Mini**. Pro Minis are available on [eBay from sellers in Asia for under $2.00](https://www.ebay.com/sch/i.html?_from=R40&_sacat=0&_nkw=Arduino+Pro+Mini&rt=nc&LH_BIN=1). At US retailers prices are between $4.00 and $20.00. Pro Minis come in 3.3v and 5v versions, and the 3.3v version is required. - **Adafruit TPL5110 Low Power Timer**. Available from [Adafruit for $4.95](https://www.adafruit.com/product/3435). - **DS3231 real time clock**. This module is available on [eBay for about $1.20](https://www.ebay.com/itm/Top-1-2PCS-Arduino-DS3231-AT24C32-IIC-Module-Precision-Real-Time-Clock-Memory/182840998778?hash=item2a922c3b7a:m:mkMwmF_bfaCkRIqfFG3yeTw) or from [US retailers for $4.00 to $15.00](https://www.amazon.com/Diymore-DS3231-AT24C32-Precision-Arduino/dp/B01IXXACD0/ref=sr_1_5?s=electronics&ie=UTF8&qid=1513187359&sr=1-5&keywords=ds3231+real+time+clock+module). Some DS3231 chips do not work at temperatures below 0°C, but these are not included in KAPtery kits. - **3.3 volt MicroSD card socket**. These modules are available on [eBay for less than $1.00](https://www.ebay.com/sch/sis.html?_nkw=10pcs+Mini+SD+Card+Module+Memory+Module+Micro+SD+Card+Module+for+Arduino+AVR+ARM&_id=331907413969&&_trksid=p2057872.m2749.l2658). There are many different microSD card modules, and some are better at low sleep current. Also required: - **Battery or battery case** for AA or AAA. The Mini Pearl Logger is a 3.3 volt device. Three alkaline batteries (3 x 1.5v = 4.5v) are adequate or four NiMH (4 x 1.2v = 4.8v). LiPo or LiPoly batteries (3.7v) are also good. - **MicroSD card**. Cards of 1 GB or smaller capacity are best if the logger will be slept (instead of turned off with a timer) because they tend to sleep better and at lower current. - **CR2032 coin cell** battery for real time clock. ###Assembly There are documents with guidance about assembling and getting started with the Mini Pearl Loggers at the [KAPtery Guides page](http://kaptery.com/guides/). ###Software A different Arduino sketch for each version of the Mini Pearl Logger can be downloaded at the [KAPtery Guides page](http://kaptery.com/guides/). Below are some research notes about activities done with Mini Pearl Loggers. Some of these notes include the sketch which was used in the activity described. ## Activities [activities:mini-pearl-logger] ## Questions [questions:mini-pearl-logger] ...
Author | Comment | Last activity | Moderation | ||
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warren | " Indeed, that's cool! Thanks! I did notice their link seems broken though - did you want to reach out to the editor? It links to: https://makezi..." | Read more » | over 5 years ago | |||
cfastie | " I just noticed that Limor Fried wrote an article for Make Magazine in January citing this research note and using one of the images. An editor ask..." | Read more » | over 5 years ago | |||
liz | "This is so useful! Another imaginative concept brought to real world utility by Chris Fastie. If I ever have a well, I will install this to learn a..." | Read more » | almost 6 years ago | |||
warren | "Tremendous! :tada: " | Read more » | almost 6 years ago | |||
MadTinker | "Just a quick update on the status of this project. Willow Creek is going through a couple of serious events. First, the stretch of the stream where..." | Read more » | almost 6 years ago | |||
MadTinker | "@cfastie FWIW I used a Kalman filter algorithm for my TDS analyses with data from a similar setup data logger setup. I believe that my original im..." | Read more » | about 6 years ago | |||
cfastie | "What do you guys think, is it okay to use the mean instead of the median? @pdhixenbaugh, @MadTinker, @Shanlter, @rockets " | Read more » | about 6 years ago | |||
hpprinter1995 | "Nice And Informative Website. Please Keep Continue Such Kind Of Effort. Contact Us And Get On-Site HP Printer Support & HP Scanner Support. Our..." | Read more » | about 6 years ago | |||
pdhixenbaugh | "I'm also looking to measure Conductivity, and I have a Riffle. So you have any advice for what sensor to buy, with the memory constraints and other..." | Read more » | about 6 years ago | |||
Paquicamus | "I have done many calibrations to correlate Conductivity vs TDS. One thing that I have found out it will only work for one Creek, river or any surfa..." | Read more » | about 6 years ago | |||
cfastie | "Fig. 6 was created using Fritzing (http://fritzing.org/home/). The annotations and some editing were then done in PhotoShop. " | Read more » | over 6 years ago | |||
overwriter | "@cfastie Cool project. I'm try to create a diagram similar to Figure 6. How did you go about creating that? " | Read more » | over 6 years ago | |||
cfastie | "The first two times I tried the Rev. P wind sensor, I also tried the Rev. C sensor. The Rev. C sensor did not work as well as the Rev. P, so I focu..." | Read more » | over 6 years ago | |||
cfastie | "It’s fairly straightforward to use the Modern Device Wind Sensors with either a Mini Pearl Logger or a Nano Data Logger. I had great success with t..." | Read more » | over 6 years ago | |||
warren | "@cfastie, what do you think? The AREN folks are asking us for some that'd be relatively quick to plug in and start logging on a kite, that could be..." | Read more » | over 6 years ago | |||
warren | "Oh no! I recycled the sour cream containers. We'll have to go eat some sour cream now. :-) I'm hoping it'll be possible to attach these to a stake..." | Read more » | over 6 years ago | |||
xose | "Master! Unmeasurable amount of work to get this. Thanks a lot @cfastie!! " | Read more » | over 6 years ago | |||
xose | "@xose awards a barnstar to cfastie for their awesome contribution! " | Read more » | over 6 years ago | |||
xose | "Amazing Christian!!! " | Read more » | over 6 years ago | |||
warren | "@warren awards a barnstar to cfastie for their awesome contribution! " | Read more » | over 6 years ago | |||
cfastie | "Yes, I agree that this is a different approach to an issue that has had a lot of effort directed at software solutions. This is a purely hardware s..." | Read more » | over 6 years ago | |||
warren | "Wow, this is really cool. I'm thinking about how to break out some of this info into a low-power-data-logging section or something. Would it be hel..." | Read more » | over 6 years ago | |||
donblair | "Great question re: whether powering the Feather on the 3V line really does work well ... I don't really know. But: looking at a schematic for one ..." | Read more » | over 6 years ago | |||
cfastie | "That's a really good point that the En pin on the Feather can disable the regulator and reduce power consumption. We need a table of all the featur..." | Read more » | over 6 years ago |