We do a lot of work with microcontrollers. We wanted to free up some projects from the power cord and let them run away from a bench. We also wanted projects that could be self-powered from sunlight or even run for months at a time. How could we do this without a power outlet or large batteries? We only needed small bursts of energy for data collection and transmission.
A small, nano-watt powered, self-managing battery charging system that provides power to the microcontroller. We've seen some ideas come and go, but if you're looking into powering your microcontrollers for a long time, this is the solution you need as well.
Athena Energy Corp's (AEC) Energy Harvester BoosterPack is the perfect power source. It is designed for the popular super low-cost Texas Instrument's (TI) LaunchPad Series of development boards, we also plan to offer a system for Arduino with your support.
- Plugs into the TI LaunchPad series of development boards
- 4 solar cells
- Lithium Ion rechargeable coin cell battery
- Battery charging/management system
- 40 Pin Prototyping area
- 3.3V regulator with ultra-low quiescent drain (Datasheet)
- External solar connection (add your own solar cells)
- External Lithium Ion battery connection (use your own battery)
- Option to measure battery voltage and create a battery gauge with MSP430
We use multiple micro-controllers and their development environments everyday. Here's why we chose the LaunchPad:
- Low cost entry into the world of microcontrollers ($4.30 for the MSP430 LaunchPad)
- Works with multiple Development Environments (Energia, IAR, CCS)
- Ultra-low power capabilites of the MSP430
- One BoosterPack fits the LaunchPad Series
- A small hardware interface already exists on the board for user input with buttons and LEDs
Wait. What's Energia?
It's ok, we said that at first as well. We started working with Arudino and loved its simple open-source programming environment; it's designed for everyone. Energia is a development environment very similar to the Arduino environment. You can read more about it here. We think that people who even aren't engineers will like the simplicity of the environment and the similar feel to the ultra-popular Arduino programming environment. We're using it as the development tool for our LaunchPad projects.
We have something we like and we want to make it better. If the following stretch goals are met, we'll make the following modifications:
$30,000 - We'll add wireless connectivity to the board. We think using a popular RF Transceiver would make this package perfect for wireless self-power sensors. We're looking at the CC1101 RF Transceiver from TI (link here), it provides good range at 900Mhz using zigbee protocol but we're open to suggestions. We want your input here. Let us know what wireless (and low power) option you would like to see. If there is a large majority that wants something else, then we can make it happen, and we will. We think an energy harvesting wireless booster pack would offer the open-source community a more simplified way to develop solar power and sensor networks. This addition will be same low cost as the original BoosterPack.
$40,000 - We will give you a choice of TI or Arduino Version (both with wireless) of the energy harvesting BoosterPack. It will be built as a compatible Arduino shield with wireless capability. You'll be able to pick between the LaunchPad and Arduino versions.
Here's where you come in:
Again, we think we have something great to offer the community. Here is where we are:
We have a protoype of the Energy Harvester. We've tested the battery management system and operation on the Launchpad board. We've been hand assembling these and know the demand will be there once we get the production line rolling.
We need your help in funding the full first run of the AEC Energy Harvester. With higher quantities of parts, the overall cost decreases (sometimes a dollar a part!) and this way we can offer the Energy Harvester at a much better price.
We're also excited about our Stretch Goals. If we see the demand to add functionality and platforms we'll go ahead and do that. Because YOU deserve it.
What happens after the funding deadline?
Once we've been fully funded, we're going to respond to multiple quotes that we have received from electronic assembly houses. These quotes gave us a good picture of how low we could get the cost when buying in bulk. Once we get funded, we'll get in touch with our assembly and get the line rolling!
With regards to Stretch Goals
When we reach Stretch Goals, we will be modifying board layouts and sending out protoypes the SAME WEEK we reach the Stretch Goals. We want these in your hands and see the amazing things YOU do with them as bad as you want them.
- What size is the button cell?
The button celll is rated at 3.6V and 110mAh. You can find more information on it here.
- How in the world is this thing going to run for a very long time? Your battery is too small!
We see your point. However, do you really need to be getting data every millisecond? What about once an hour? Or when a passive interrupt is activated? To maximize battery life, we recommend you sleep your device when you don't need it. Also whenever there is any kind of light (sun, ambient, florescent), the Energy Harvester will be gathering energy.
- It's cool, but what can I do with it?
We're planning on making a solar insolation station for monitoring sunlight conditions. You could add a photosensor to measure rainfall, detect smoke, monitor your pet's waterbowl, tell you if a door was left open, check the soil moisture in your garden, or use the internal thermometer and relay to turn on and off your air conditioner or heater. You get the idea...
- What solar cells are you using?
We are using the IXYS KXOB cells found here.
- What is the power output of your solar cells?
Each solar cell has a rating of 22.3mW. We're using 4 panels to give a total power of 89.2mW. This assumes ideal termperature and light conditions.
- Well that's not enough power for me. What is the largest solar panel that I can use?
You can use up to 310mW of additional solar power for a total of 400mW. This is the limit of the energy harvesting controller.
- I thought solar panels only work in direct sunlight. Can you give a better explanation on how this works?
In short, the panels charge a tiny intermediate energy storage capacitor. Once this capacitor reaches a certain charge, the stored energy in the capacitor is harvested and put towards charging the battery. It will harvest energy in direct sunlight in a larger quanity than ambient indoor lighting. Feel free to research the IC we use, the BQ25504. The datasheet is found here.
- (30 days)