Tag Archives: energy meter

GridVortex talks Atmel on LinkedIn

Jonny Doin, the founder and CEO of GridVortex Systems, recently explained why and how his company uses Atmel microcontrollers (MCUs) in a series of LinkedIn posts.

First off, Doin said he was quite pleased with the support he’s received from global Atmel staff in various locations, including San Jose, France, Spain and Germany.


“We needed support for the crypto core details for the CPKCL and promptly [kicked-off] a teleconference with the crypto guys in France,” he wrote. “I now try to use Atmel parts in all my projects.”

In terms of specific silicon, Doin said:

“If you need a Cortex-M that does serious crypto operations, consider using an [ARM-powered] SAM4C16 from Atmel. It is a dual Cortex-M4 with 1MB/2MB Flash, 128K/256K RAM and very strong crypto support. The chip is targeted [at] Legal Metrology and offers secure hardware crypto to support TLS/SSL.

“It [also boasts] hardware support for ECC512, RSA1024, independent circuitry for AES and a subsystem that monitors memory areas and generates exception when the hash of the area changes. From what I saw, [this] is the fastest ECC512 engine in a microcontroller, [although it does not] tax the MCU cores. [Yes], you will need a crypto NDA to get access to the crypto hardware documentation, but the ECC crypto API is really complete. The timings are impressive and outperform [other microcontrollers].”

Doin also noted that he is currently testing an Energy Meter that includes an ARM-based SAM4C.

“Atmel has won almost all chips on my design. I am using the SAM4C, ATM90E25, AT86RF212B and the LED controllers from mSilica, MSL20xx. I try to use Atmel parts in all my projects. The IPv6 router for my mesh networking is being designed around the SAMA5D3. The intelligent nodes in the mesh are SAM4C16+AT86RF212B. My software defined LED power driver is being built around the SAMD10/MSL20xx and our intelligent smart vision cameras will also use Atmel processors.”

In addition, Doin confirmed that his company was in the process of designing its endpoint hardware with the SAM4C16.

“The documentation is really good, and so far we just got everything we needed directly from the datasheet,” he added. “Maybe we’ll [also] decide to use a SAM4C32 in one of our designs, so I am looking forward to the updated datasheet.”

Last, but certainly not least, Doin said he successfully designed a high-precision servo-DAC using delta demodulation and one of the center-aligned PWMs of the SAM4C16.

“Using just one digital output and one ADC input I achieved a very stable, precision DAC, at under 19cents of external discrete components. I [recently showcased] the DAC prototype at a recent meeting in Atmel San Jose. I plan to publish the design as an AppNote for the SAM4C16 (and also for the ATmega, which also has the same PWM) and present it as a lecture at the next Embedded Systems Conference,” he concluded.

Interested in learning more about Atmel’s portfolio for your next project? You can check out a detailed breakdown of our microcontrollers here.

Video: Designing an Uno-based energy meter

Electrical engineer Debasish Dutta has designed an energy meter built around an Atmel-powered Arduino Uno (ATmega328 MCU).


“I [come from the] village of Odisha, India, where frequent power cut are very common. Continuing studies after dusk was a real challenge [so] I designed a solar system for my home on a experimental basis,” Dutta explained in a recent Instructables blog post.

“I used a solar panel of 10 Watt, 6V for lighting few bright LEDs. Then I decided to monitor the voltage, current, power and energy involved in the system, [which inspired] the idea of designing an energy meter.”

Dutta said he chose Arduino as “the heart” of his energy meter due to the numerous available open source libraries and intuitive IDE environment.

Aside from the Arduino Uno, key project features and specs include:

  • 16×2 character LCD display
  • Arduino Ethernet shield
  • ACS 712 current sensor
  • Resistors (10K,330ohm)
  • Potentiometer (10K)
  • Jumper wires
  • Ethernet cable (CAT-5E)
  • Bread board
  • Supports Xively upload
  • SD card data logging

The energy meter uses three primary parameters to measure energy consumption: voltage, current and time.

“Voltage is measured by the help of a voltage divider circuit. As the Arduino analog pin input voltage is restricted to 5V I designed the voltage divider in such a way that the output voltage from it should be less than 5V. My battery used for storing the power from the solar panel is rated 6v, 5.5Ah. So I have to step down the 6.5v to a voltage lower than 5V,” said Dutta.

“I used R1=10k and R2 =10K. The value of R1 and R2 can be lower (one), but the problem is that when resistance is low, higher current flow through it. As a result, a large amount of power (P = I^2R) is dissipated in the form of heat. So different resistance value can be chosen but care should be taken to minimize the power loss across the resistance.”

For current measurement, Dutta used a Hall Effect current sensor ACS 712 (20 A), while leveraging the Uno’s built-in timer. The collected data is then uploaded to Xively.com for additional analysis.

Interested in learning more? You can check out the project’s official Instructables page here.