Kit Reviews: Snootlab Power ScrewShield and I2C Power Protoshield
In this article we will examine the first two products from a bundle sent for review by Snootlab, a Toulouse, France-based company that in their own words:
… designs and develops electronic products with an Open Hardware and Open Source approach. We are particularly specialized in the design of new shields for Arduino. The products we create are licensed under CC BY-SA v3.0 (as shown in documents associated with each of our creations). In accordance with the principles of the definition of Open Source Hardware (OSHW), we have signed it the 10th February 2011. We wish to contribute to the development of the ecosystem of “do it yourself” through original designs of products, uses and events.
Furthermore, all of their products are RoHS compliant and as part of the Open Hardware commitment, all the design files are available from the Snootlab website.
First, let’s examine the Power Screwshield kit. This is a feature-laden prototyping shield suitable for Arduino Uno and compatible series boards. It can be used with the Mega, however not all of the I/O pins will be available.
Apart from obvious use as a prototyping shield, there are also three other useful features:
- space for a 16-pin SOIC SMD part in the prototyping area;
- a full line of screw terminals that connect to all the shield pin connections (in a similar way to the Wingshield Screwshield);
- and a socket to allow power to be sourced from a standard computer ATX power supply, which brings 5V and 12V DC to the shield. I have never seen this implemented on a shield in the past – a very novel and useful idea.
… which contains all the necessary parts:
… and a very high quality PCB:
The PCB thickness is over 1mm, and as you can see from the image above the silk-screening describes all the areas of the PCB in a detailed manner. Note that this shield is much larger than a standard Arduino shield – this becomes obvious when compared with a standard prototyping shield:
Assembly was very smooth and quick. There are a couple of things to watch out for, for example you need to slide the terminal blocks together so that they are flush on the sides, such as:
… if you want to enable the 12V DC rail from the ATX power lead, short out the jumper SJ1 with a blob of solder:
… when soldering the PC power connector, be sure to make the clamp bracket flush with the socket, for example:
… and finally, to enable use of the shield’s LED, you need to cut the track in this area on the underside of the PCB:
Although at first the introduction of another Arduino prototyping shield may not have seemed that interesting – this version from Snootlab really goes all out to cover almost every possible need in a shield all at the same time. Sure, it is a lot larger – but none of the board space is wasted – and those terminal blocks would be very hand for making some more permanent-style prototypes with lots of external wiring. And the ability to accept power from a PC ATX-style power supply unit is certainly original and possibly very useful depending on your application. So if you need to create something that needs a lot of power, a lot of prototyping space, and a lot of wiring – this is the protoshield for you.
For the second half of the review we have the Snootlab I2C Power Protoshield. This is another example of an Arduino prototyping shield with some interesting twists. Apart from employing the same PC power connector as used with the Power ScrewShield, this shield is designed for hard-core I2C-bus enthusiasts. (What’s I2C? Check my tutorials). This is due to the 10-pin HE connector on the edge of the board – it contains pins for SCL, SDA, 3.3V, 5V and GND. With this you could use you own cable connections to daisy-chain other devices communicating via the I2C bus. Again, the shield is a kit and assembly was simple.
Like other Snootlab products, the kit arrives in a reusable ESD bag:
… with a high-quality thick PCB that has a very detailed silk-screen layer:
… and all the required parts are included:
When soldering in the shield connectors, using another shield as a jig can save time:
And we’re finished:
One could also mount a small solderless breadboad on the I2C Power Protoshield:
One great feature is the inclusion of an NCP1117DT33 3.3V 1A voltage regulator. Using this you can source 3.3 volts at up to one amp of current (only) when using the PC power supply connection. This is a great idea, as in the past it can be too easy to accidentally burn out the FTDI chip on an Arduino Duemilanove by drawing too much current from the 3.3V pin. The use of the external 3.3V supply is controlled by a jumper on the header pins here:
Finally, in the image above you can see the area for external I2C pull-up resistors. Generally with our Arduino the internal pull-up resistors in the microcontroller are adequate, however with many I2C devices in use (e.g. eight 24LC512 EEPROMS!) external pull-ups are required.
After examining the two shields I am impressed with the quality of the components and PCBs, as well as the interesting features described in the review. Theyare certainly unique and very much useful if required, especially the PC power supply connections. Support is available on the Snootlab website, and there is also a customer forum in French (use Google Translate). However the people at Snootlab converse in excellent English and have been easy to contact via email if you have any questions. Stay tuned for more interesting Snootlab product reviews.
As always, thank you for reading and I look forward to your comments and so on. Furthermore, don’t be shy in pointing out errors or places that could use improvement. Please subscribe using one of the methods at the top-right of this web page to receive updates on new posts, follow on twitter, facebook, or join our Google Group.
[Disclaimer - the products reviewed in this article are promotional considerations made available by Snootlab]
Otherwise, have fun, be good to each other – and make something!