Evaluation Type: Independent Products
Did you receive all parts the manufacturer stated would be included in the package?: True
What other parts do you consider comparable to this product?: -
What were the biggest problems encountered?: The first device I got was not working at all, but I quickly got a replacement.
Let’s face it: Cleopatra and Nero aren’t the smallest names in human history. So when a company announces two products inspired by these names, the expectations are high. I was lucky enough to be selected to roadtest these items: Nero is an Arduino compatible board, with an onboard power supply able to source 1A. The Cleo35 is a 320x480 pixel TFT LCD touch screen and ideally, they will form the perfect marriage.
To start with the Nero: this is a pretty looking board, with a well designed PCB layout. It's equipped with long headers that can be used to attach the Cleo on one side, while still having access to the standard Arduino headers on the other. In a configuration like this, one has to keep in mind that not all pins can be used for other purposes: four digital pins are claimed by the Cleo. As well as the SPI pins, which of course could also be used as digital pins without the Cleo on top. I couldn’t help noticing that the soldering of the headers could have been cleaner: there where little blobs of solder on top of the pins, as we can see in figure. It also must be said that the layout of the board looks good, that quality components have been good and that the smd soldering is straight and solid.
The main feature of the Nero is the onboard buck converter, which can source up to 1A by 5Volts, without overheating. A normal Arduino is usually equipped with a lineair voltage regulator (ldo). They are cheap and will conveniently convert the voltage of the source, to the desired voltage. For an Arduino is that 3.3Volt or 5Volt. This conversion, however, is far from efficient. If we convert 12Volts into 5 Volts with an ldo, in an application that uses 1A, that would mean 5*1 = 5 Watts are consumed by the application. But the remainder, 7*1 = 7 Watts will be converted into heat. In other words: far over 50% of the battery capacity will be wasted. And since the wasted energy is fully converted into heat, we quickly run into heat problems if we try to source too much power from and ldo.
This is where the buck converter comes in. For this review, it’s sufficient to say that buck converter uses a switching circuit, in combination with an inductor and a few capacitors to reduce the voltage to a lower level, without wasting so much of the energy as an ldo does. The result is that we can source more power from the buck converter, without wasting battery capacity and running into heat problems. I decided to put it to the test right away and placed a 5.7 ohm resistor between the 5V output and GND. This will result in a current of almost 0.9A and a power dissipation in the resistor of 4.4 Watt. As we can see on the photo, that is way too much energy for a simple 0.25 Watt resistor. It started smoking first and then glowed up red. Just keep in mind, that an LDO converting 12 volts to 5 volts would dissipate even more energy! I repeated the same trick with a ceramic resistor of 5.6 ohm. That one did survive and I let it sit there for a while. Although the resistor heated up to the point where it became unpleasant to touch it, the board itself remained cool. So I think it’s safe to assume the claims of FTDI are true: we can source at least up to 1A from this board.
All in all the Nero is a nice board. A critical note is the MCU of choice: the Atmega328. Of course, it makes the board conveniently Arduino Uno compatible, but the 328 has it limitations. Especially combination with the Cleo, that will use both the SPI and a couple of digital pins as resources. However, that should not be a reason not to buy the Nero, when in need of an Arduino with a proper power supply. I am happy to have in in my collection now. And the price for the device is more than reasonable: a little over 21 euros at Farnell. Including VAT that comes down to about 25 euros in The Netherlands. That makes the Nero a very affordable Arduino clone, manufactured with quality by a respectable company.
Of course, I was also anxious to try out the Cleo35. Unfortunately, that turned out to be a little bit problematic. While unboxing, I noticed the packaging had been opened before. The same applied to the Nero. I assumed I just received a review copy that had been tested by others as well. No big deal. I attached the Cleo and it showed me the startup screen. But after I followed the installation procedure which is well described on the dedicated website http://cleostuff.com. The screen turned black and never went on again, no matter what I tried. I took a closer look at the pcb and to my big surprise it not only showed signs of rework, it also had traces of flux or even corrosion on it, as we can see in the photo: watch the green residu between the components.
Of course, I mentioned the issues to FTDI. After swapping some more details about the nature of my technical problems, we came to the conclusion that is must be a hardware problem and the Cleo was replaced with a working one. From then, everything was pretty straight forward. The website mentioned earlier offers tons of information, as well as loads of examples on how to use the Cleo and updates to the preinstalled firmware.
The Cleo uses processing power of its own to create the graphics, so that the demand on the Arduino is relatively small. Another nice feature is the desktop software for the Cleo. With this program we can not only update the forware, we can also convert media files into a format that we can use with the Cleo. The resulution of the Cleo is good enough, but not great. It’s slightly behind today’s expectations, but they may be a lillte bit too high when using OLED smart phones on a daily basis. The sensitivity of the touch screen is good and it since it’s based on resistive touch, it responds to everything that presses on it.
In the end, the Cleo is a well working display, that can easily be combined with either a normal Uno, or the Nero. I would have definately recommended it to my students, if the price would have been lower. Farnell now offers the Cleo35 for 82 euros. With VAT added, in the Netherlands that would come donwn to about 100 euros. From my experience, for many hobbyists and most students that is more than they can spend. And quite frankly, for that money I’d like to see better specs for the display. On the other hand, it's obvious that a fair amount of investment has been done in the development of the Cleo. This a applies to both the hardware and the software. So we should not make the mistake to relate the pricing of this device to the never ending stream of extremely low priced and poorly produced copies and counterfeits on the open source market.
Nero and Cleo35 are a nice couple, for sure. I am happy to have them in my Arduino collection and at some point I will definately use them for a more power consuming project that includes visual feedback to the user. Something that most Arduino projects simply don't have yet. The Nero is a well designed board, with a proper working buck converter on board. So it's more than just the next Arduino clone on the block and it comes at a very reasonable price, especially when taking the quality of the board into consideration. Cleo is a well designed LCD touchscreen add on, that is easy to use and puts relatively low pressure on the Arduino core. Just like the Nero, this device is a great addition to the collection, for everyone who is working with Arduino's on a regular base. Downsides is the price, which is on the higher side. But it's working out of the box, as promised and that's also worth a lot.