A Low Power Arduino Board - Designed for Solar!
The Arduino family of processors is a fabulous prototyping and building system for Makers. The combination of the Arduino IDE with its thousands of available drivers for sensors and the ATMega line of processors have spawned a tremendous burst of creativity around the world.
At SwitchDoc Labs we have been building and writing about Arduino projects for years. From Project Curacao in the tropics to specialized Arduino based solar powered weather stations, we have extensively used these devices in many ways.
12/9/2017 Update: Now at 16MHz clock speed
The Grove Pro Mini LP Board in the Sunshine!
Solar Grove Mini Pro LP Far From Home (430 meters) powering the WXLink kit from SwitchDoc Labs
In building all these projects with off the shelf Arduino devices we realized that we were missing two features.
And this is why we are building the Grove Pro Mini LP.
We redesigned the Arduino Pro Mini LP board to be very low power. We removed the regulating power supply, modified the circuit to run the processor at 8MHz and provided 3.3V and 5V compatibility. Whew! And the engineering prototypes work! We have about another week of testing and we should be able to release to production. That means we will should ship this Kickstarter on time!
Each Grove Pro Mini LP Board ships with a plug-in DS3231 highly accurate RTC (Real Time Clock) that can be used to wake the Grove Pro Mini LP up at regular intervals or even on specific dates! (Software provided).
What is the Arduino Compatible Grove Pro Mini LP?
Below is an annotated picture of the Grove Pro Mini LP showing all of the connections available.
Annotated Grove Pro Mini LP Board - Grove everywhere!
All those Grove Connections for IOT Prototyping Goodness!
JP4, JP5 and JP6 preserve the original Arduino Pro Mini Pinout.
The Grove Pro Mini LP keeps the Arduino Pro Mini Pinout
The Grove Pro Mini LP has the pinout of the Arduino Pro Mini LP but has been modified for low power. Here is a comparison of power used by various Arduino devices compared to the Grove Pro Mini LP:
Grove Pro Mini LP Power Consumption
Our design goals were 2mA sleeping at 5V and 1mA sleeping at 3.3V so we beat our design goals! Less power means more battery life and smaller and cheaper solar power systems.
To go solar you need a low power processor unless you want BIG Solar Panels. We are providing in the rewards two inexpensive sizes of Solar Panels and if you want to go bigger, there are the excellent panels from our buddies at Voltaic Systems.
Testing our Solar Panels
SunAir and SunAirPlus boards are solar controllers and chargers from SwitchDoc Labs. The main difference between them is that SunAirPlus allows you to collect and see all the data from the solar panels, battery and the power for the Mini Pro LP Board.
Battery Operated IOT Device
This device uses the Mini Pro LP to control an ESP8266 for WiFI (turning it off between transmissions for power considerations) while read the temperature and humidity from a Grove AM2315 and a Grove Sunlight Sensor (reading visible, infrared and UV) through the I2C interface. Powered straight from a LiPo batter. All ready to go solar!
Our WXLink Radio Application
One of the inspirations for this project was the previous kickstarter we did, "The Weather Board for the Raspberry Pi". One of the devices that the Weather Board connects to is the SwitchDoc Labs WeatherRack wind and rain sensor.
WeatherRack Wind and Rain Sensor
The issue is sometimes you don't want to run a wire all the way from the Weather Station to the wind and rain sensor. Like all the time. So, using the Mini Pro LP, we build a solar powered WeatherRack reader and then we use a transmitter to send it back to the station inside the lab. Did it on an average power of less than 5mA which made solar power easy to add. No power. No wires. More on this project in the next few weeks. Here is the complete project on a walkabout near the Spokane river. 433 meter (1,473 feet) range. Amazing for a little solar powered device!
Solar Powered Mini Pro LP on a Walkabout
More applications to come!
The way we have been wiring I2C connections before just didn't work for building fast and quick IOT projects. Then we found Grove.
There are hundreds of Grove Devices from multiple manufacturers around the world. Just check out Seeedstudio. Just for a quick look at over 100 boards.
You can't plug it in backwards. If you put the connector in the wrong plug it just doesn't work. No smoke. No fire. This makes us happy as we look over into our Box Of Death, filled with boards we have ruined. No more additions to the BOD! Well, hopefully. Have faith.
We quickly found the connectors and their respective cables very useful. With the large selection of Grove I2C devices available, we decided to include a Grove connector on all our future boards and products.
For more information, check out our full Grove Tutorial here.
For up to date information on Grove, you can check out our GroveWeekly Newsletter here.
Yes, this board is designed to be compatible with Arduino devices. But, wait, there's more. We designed it to be 3.3V and 5V compatible, so it works perfectly with a Raspberry Pi based processor. It can work with the ESP8266 too (since the Pro Mini LP will work at 3.3V).
Our beloved (most of the time) CTO, Dr. John Shovic, always insists on putting in something about the theory behind the board. Here are his thoughts.
"We build a lot of solar powered devices around SwitchDoc Labs. Projects for books, project for articles and customer specific devices. The thing we were missing was an easy way to build prototypes or one-off devices for experiments or customers that are robust and easy and quick to wire up. That was the thought for Grove connectors. The second criteria is that we had to get the power way down from the Arduino. At least 10 times lower. That would give us solar power flexibility that we have not been able to achieve with the normal Arduino or the Raspberry Pi. We looked at the entire board and did away with anything that was not strictly necessary and worked on the power consumption that was left.
One key piece of the design was to make sure we could put the processor to sleep and then wake it up from internal and external sources. The interrupts are set up that way. Then we added the optional DS3231 (included with your board) to provide a whole new set of external wake up possibilities. I'll admit that this board is fun to play with."