The JeeNode Micro is the powerful little brother of the JeeNode. The key difference is that it’s based on the ATtiny84 processor with 2 ports instead of 4. It’s also considerably smaller: 15 x 47 mm, and less than 4 mm thick from using a thin PCB and the extra-flat version of the HopeRF wireless module.
Software development can be done with the Arduino IDE – but this does require some extra hand-holding and software support, see the Arduino-Tiny library and this project for more information on how to do this. The JeeNode Micro (or JNµ) is currently aimed at advanced developers & makers – you will need an ISP programmer to upload the firmware and there is no hardware/software support to debug or communicate through.
The JeeNode Micro normally runs at 8 MHz, but the JeeLib library will work with the ATtiny84 down to 4 MHz.
Version 2/3 added logic for very lower power operation – the HopeRF module can be completely disabled by the ATtiny, allowing for slow-startup energy harvesting power sources. For extra flexibility, new options are available for selecting the power source that matches your application:
- 2.2 .. 3.8 V, fed from a coin cell, 2x or 3x AA, rechargeable or ‘dry’. Lowest quiescent current draw.
- 3.5 .. 5.1 V, fed via dropper diode(s) e.g. 4.2V Lithium, 5.0V from a powered USB hub or a mains adapter (check < 5.1V unloaded output). Low quiescent draw but some energy lost across the dropper diode(s).
- 0.9 .. 5.1 V, fed in through the “PWR” pin with the optional Boost circuit (coin cell must be removed). Higher quiescent current but stabilized 3.0V logic power rail.
The Direct Power JeeNode Micro is pre-assembled. A great option for lowest consumption, battery-powered use. It does not include a voltage regulator so select a power feed in the range of 2.2 .. 3.8V, such as 2x AA batteries, or mount a 3V Lithium coin cell holder in the space provided (the CR2032 coin cell and holder are not included). Alternatively, connecting a 4.2V LiPo battery by adding series forward-drop diode, or use a 5.0V external supply (check < 5.1V unloaded output) with two series diodes.
The Boost power JeeNode Micro is pre-assembled and adds a similar circuit to the AA Power Board. This allows powering from as low as 0.9V through to 4.5 V. The quiescent current is a little higher to keep the switching convertor chip alive. The CR2032 coin cell and holder are optional.
The PCB only variant is the bare board without any components. You’ll need to add your own ATtiny, HopeRF, pin headers, and a few other components to create a working JeeNode Micro. This board uses SMD parts of size 0603 – you will need to use proper SMD tools and soldering technique to assemble a JeeNode Micro yourself.
Note: The JeeNode Micro is not yet compatable with the RFM69C radio module, but may be in the near future!