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Posts: 30
Registered: ‎09-12-2016

EFM8-Powered Plug And Play Solar Concept

[ Edited ]

Hey everyone,

 

I used the EFM8UB1 starter kit to complete construction of my plug and play solar system concept. The goal of the concept is to make solar system installation as easy (and hopefully) as cheap as possible by reducing the amount of on-site assembly required.

 

It has a built-in inverter, charge controller, 12 Volt, 12 Ah UPS battery, 12 Volt solar panel input, a 5 VDC power rail for a later centralized USB power project, and 120 Volt AC outlets. You just connect a solar panel, flip a switch, and you have a 120 VAC solar power source.

 

I used the EFM8UB1 to construct an automatic transfer switch for it, so it can automatically switch appliances (or a house, if it is scaled up) to the grid if there is a shortage of solar power. This is convenient for those who want to minimize battery costs without running the risk of a blackout.

 

Here is a video of me discussing and demonstrating it. 

 

The EFM8 made it very easy by providing the option of a low-energy USB port (which the white USB cable is connected to) and a built-in CR2032 battery slot.

 

This is important because it is battery-powered, and I couldn't afford to have it deplete the battery during a cloudy week, or in general: wasting the power generated by the 20 watt solar panel that recharges it. 

 

In addition to that, the analog-to-digital converter configuration was very quick and easy.

Posts: 30
Registered: ‎09-12-2016

Re: EFM8-Powered Plug And Play Solar Concept

I also wrote a GPIO introduction for the EFM8UB1 on Kompulsa: https://www.kompulsa.com/getting-started-silicon-labs-efm8-basics/

Posts: 8,176
Registered: ‎08-13-2003

Re: EFM8-Powered Plug And Play Solar Concept

When a pin is ON/HIGH on the EFM8UB1 (and most other MCUs), it is supplied with a very small current (often in the order of microamps, denoted by the uA symbol) at 3.3 volts. 

 

what about configuring the pin as push-pull?

erik
Posts: 2,384
Registered: ‎10-14-2014

Re: EFM8-Powered Plug And Play Solar Concept

@nikodean1

You could get the drive capability of GPIO in the datasheet of EFM8UB1, see detail in figure 4.6 and figure 4.7 in page 24 and table 4.13 in page 19.

WeiguoLu
Posts: 8,176
Registered: ‎08-13-2003

Re: EFM8-Powered Plug And Play Solar Concept

with all the mistakes instead of "getting started" it should be renamed "how I got started"

erik
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Posts: 30
Registered: ‎09-12-2016

Re: EFM8-Powered Plug And Play Solar Concept

Hi Erik,

 

By 'it is supplied', I meant that the MCU supplies the pin with the small current. That article is not intended to be a full GPIO tutorial, just a guide to help people get started quickly.

Posts: 30
Registered: ‎09-12-2016

Re: EFM8-Powered Plug And Play Solar Concept

Thank you! I added it.

Posts: 8,176
Registered: ‎08-13-2003

Re: EFM8-Powered Plug And Play Solar Concept

[ Edited ]

you still should change the title, what you have written is, by no means comprehensive, even about the subjects you discuss

 

"how I got started" would be a fair title

 

By 'it is supplied', I meant that the MCU supplies the pin with the small current

configured correctly it can supply 20mA

 

your 'article' reminds me of my first microcontroller project, there was a few things that was a "working implementation" but, by no means, how I would have done them after gaining more experience.

erik