NerO – An Energy Efficient Arduino UNO Compatible Design
This project started out as an accessory for another planned KickStarter project – a smart TFT display for Arduino called CleO. Now, the display itself required 150mA current, fine, but when you add a camera with its LED lights, this goes up to 250mA and if you have 1W audio playing simultaneously, unlikely,but possible, then it would require 450mA of current at 5V in order to guarantee operation. You could the USB jack to supply 500mA power, but this doesn’t leave much headroom to power other Arduino shields, so connecting a PSU to the DC jack seemed to be the answer. This started us thinking – well, the LDO regulator on an UNO and compatible boards is rated at 1A **but** how much current can you actually take without the regulator overheating and shutting down. We decided to measure it on a genuine UNO R3 board at 9V and 12V input, and the answer was surprisingly low especially with a 12V supply. Our measurements and test methodology are shared with you below.
The UNO R3 is the staple of most Arduino based projects but it’s been around for a number of years and many of the features have been improved for example by Adafruit and Sparkfun who make excellent enhanced UNO compatibles. However, our additional requirements for a full 1A current without excess heat dissipation and FCC/CE conformity led us to consider a new 3rd party UNO compatible reference design that met these requirements hence the inspiration behind NerO. We were delighted with the results of our prototype so we decided to make it available in its own right for anyone to use. On launch we will make the NerO schematic and pcb design files available publicly as a reference design under OSHWA ( Open Source Hardware Association ) terms and welcome the community to benefit from our original design work.
NerO – Specification and Enhancements.
- 16MHz ATMega328 MCU with Optiboot Bootloader
- VIN Input voltage – 7V to 20V ( 9V or 12V recommended )
- UNO R3 form factor
- 14 Digital I/O Pins (6 PWM outputs)
- 6 Analog Inputs
- FTDI FT231XS USB UART interface
1. Micro USB connector
2. Status and PWR LEDs moved to edge of PCB – and remain visible when a shield is placed on the expansion connectors
3. On-Off Switch for added user convenience
4. FTDI FT231X USB UART ( Note 1 )
5. 5V Switching regulator vs LDO regulator ( Note 2 )
6. FCC/CE certified ( Note 3 )
7. Quality product – manufactured in Europe ( Note 4 )
Note 1 – FT231X is one of the latest X-series family of USB UART solutions from FTDI. It has larger communication buffers at a lower cost compared to our popular ubiquitous FT232R device. FT231X has 3.3V output levels and 5V tolerant inputs. FTDI provide drivers for its USB bridge devices across many platforms including certified drivers for Windows, including Windows 10.
Note 2 -The NerO Buck Switcher regulator is much more energy efficient than an LDO device especially at higher Voltage inputs. It can supply a full 1A current at 5V without breaking sweat, or anything else.
Great in all circumstances where external power is used – especially for designs with higher power requirements such as driving displays/LEDs/ Wi-Fi etc. An excellent solution for for 9V battery powered solutions, automotive ( 12V ) and POE designs as well.
Note 3 – NerO is FCC/CE certified as is the original UNO, and so is suitable for commercial applications as well as hobbyist/maker projects. Most other compatibles are not FCC / CE certified. NerO is manufactured using quality manufacturers and components and, despite this, is still priced at an affordable level ( under $20 US ) for all. Our Kickstarter backers can enjoy a 25% or more discount on the R.R.P.
Note 4 – As mentioned above, manufacturing quality is very important to us – so we have partnered with MikroElektronika in Europe to manufacture our NerO using their advanced SMT assembly line. We plan to show you around their production line in a coming Project Update.