Photo: the emonGLCD by openenergymonitor.org
The second part of a post reviewing what is available to the hobbyist in terms of open source hardware for wireless sensing networks. This time I look at a series of kits that are compatible with the JeeNode from JeeLabs.
The second part of a post reviewing what is available to the hobbyist in terms of open source hardware for wireless sensing networks. This time I look at a series of kits that are compatible with the JeeNode from JeeLabs.
One of the
key design challenges with any modern electronic device is the age-old problem
of how do you get the power in and the data out? A bi-directional low power wireless link
solves the second of these problems, and innovative use of low power
electronics, rechargeable batteries and possibly a tiny solar PV panel solves
the first.
So with a
low power microcontroller and a short range wireless transceiver you have the
basis of a smart wireless node – which can be used for a variety of sensing on
control applications. The ability for it
to communicate with web connected devices – via the wireless to Ethernet bridge
opens up a vast number of possibilities for remote sensing and control. With
the availability of open data services – such as Open Energy Monitor and Cosm,
there is an easy route to get sensor data up to Cloud based servers from where
it can be processed, graphed or mapped using appropriate data manipulation
tools.
Having
decided in principle upon a simple Ethernet to Wireless bridge, then comes the
task of supporting a range of diverse wireless nodes. Range tests have shown
that the RFM12 has a useful range of 100m in the household environment, opening
up a whole host of possibilities for wireless energy monitoring, central
heating control, solar pV monitoring or other wireless gadgets that just need
to get a few bytes of data up to a central server.
Through
suppliers such as JeeLabs, Open Energy Monitor, Wicked Device and Nanode Ltd
there are starting to become available a wide range of compatible wireless
devices aimed at low cost wireless sensing and control applications. These
devices all use the RFM12 library code as developed by JeeLabs for the JeeNode,
and generally devices from different vendors may be mixed and matched.
A short
summary of some of the devices.
The original
wireless node by Jean Claude Wippler of JeeLabs. A simple combination of an ATmega328
microcontroller and RFM12B wireless transceiver on a small pcb. JeeNode utilises the concept of 4 identical
ports into which a wide variety of functional modules can be plugged to extend
the basic system. For full details see
the comprehensive JeeLabs site.
emonTx
A development
of the basic JeeNode, designed specifically for electricity monitoring
applications. It has 3 current
transformer interfaces, and voltage, pulse and temperature inputs. emonTx forms
the basis of the Open Energy Monitor – see OEM website for more information.
emonGLCD
One useful kit, is the emonGLCD wireless
graphical display from Open Energy Monitor. This consists of a 128 x 64 pixel
graphic LCD with an ATmega328 and the Hope RFM12 wireless transceiver. Whilst
originally designed to display data from the energy monitor, the GLCD may be
used to display any data – either that generated locally, or generated from a
web based application. The versatile
GLCD has three user push buttons “Up”, “Down” and “Enter” allowing the user to
select items or parameters from a menu an modify them, or select particular
modes. My first intended application for the GLCD is as a user interface for a
smart central heating controller.
In addition
to the user push buttons, the GLCD has a LED backlight, a bicolour LED to show
for example the status, and a LDR light sensor. The LDR may be used to determine whether it is
day or night, or whether the room lights are on – suggesting that the room is
occupied. To complete the usefulness of
the device, an on board 18B20 temperature sensor allows the room temperature to
be measured, allowing the GLCD to be used immediately for smart thermostat
applications. As with all the wireless
devices offered by Open Energy Monitor, the GLCD is firmware compatible with
JeeNodes, Nanode RF and WiNode.
WiNode
WiNode is
the first standalone wireless sensor device from Nanode Ltd. It is aimed at wireless sensing and control
applications, and has a number of features not found on other devices.
1. Motor driver IC for driving 2 motors, 4 relays or even a loudspeaker. Accessible via screw terminals.
2. 4 general purpose analogue inputs with voltage scaling networks. Accessible via screw terminals. Could be used for current transformers or opto-reflective pulse counters (gas meter)
3. microSD card – for datalogging or file storage. Can be used to store audio files for playback via loudspeaker
4. 32K battery backed SRAM – retain data during a power outage
5. Real Time Clock and Calendar with alarm wake-up function.
Air Quality Egg - by Wicked Device
This is a new development this year from our friends at Wicked Device and Sensemakers/Cosm.
Photo: Wicked Device.
On the left is a stripped down Nanode RF - fitted with the Air Quality Egg sensor shield - a series of plug in gas sensors to allow measurements of typical air pollutants to me measured and sent up to a open data server - provide by Cosm.
2 comments:
Hi, after reading this awesome piece of writing i am as well delighted to share my familiarity here with colleagues.
www.schnap.com.au
e cigarette, electronic cigarettes, e cigarette reviews, e cigarette, smokeless cigarettes, ecigarette
Post a Comment