The Microduino-Core is a tiny little thing that is very functionally modularized. The example given on the web site is the MCU and support circuitry on one board and the USB to serial converter on another. That means you pay for the MCU every time, but the USB converter only once. The Core sells for $8.00 and the USB module for $12.00. The total cost of $20.00 might seem high for a pair of boards you can hide behind 50 cents in quarters, but if you buy two Core modules, and only have to buy one USB module, you make out pretty well.
Many of the Arduino and clone boards require a separate USB to serial converter cable that can cost up to $20.00, and the boards still sell for around $20.00. We've tried to shoot holes in this, but can't. It is just a good deal, and a great way to build a tiny little computer. If you already have a USB to TTL serial cable, you can wire it up to this board with a little ingenuity and a 0.1uF capacitor. This is the same thing you get with the Arduino Pro and Pro Mini, and for a lower cost. Flat rate $10.00 shipping and a long wait from Hong Kong are downsides. It would be nice if their US office shipped to the US.
The temperature data logger was made just to see how big it would be. It is very small. We don't have the obligatory US quarter to demonstrate how small it is, but you get the idea. It is logging the room temperature to a 32GB micro SD card every second.
Any type of Arduino shield you can get is likely to have a counterpart for the Microduino-Core. One thing you won't find is a mixed shield, where the Arduino Ethernet shield has an SD card socket, for example, two different modules supply these functions for the Microduino-Core. It is a problem with real estate - there isn't any.
The fault we found with the Microduino was the lack of documentation. Eventually a test program turned up, which had the correct chip select pin (7) for the SD card, and in five minutes we had a data logger. There is a documentation page on the SD card, but it has no specific documentation at all - only general Microduino info. The images are empty, and link to a generic front of site page.
|Operating Voltage||5 / 3.3|
|Test Current Draw||20.8mA@5V|
|Web Site||Microduino Studio|
The concept is that the system is less expensive because the USB module is only used to program the system, but in fact the only way to power it is via the USB module, which provides the 5V and 3.3V supplies to the rest of the modules. There is a battery power management board, but it is a little unhandy in practice. To help with our project we built a little board using male - male machined headers and a piece of perfboard. That board was outfitted with a 5V regulator and a 3.3V regulator - both SOT-223 packages. The battery pack contains a pair of AAA batteries - total voltage 8.1V. There is no charging circuit.