Currently Gridspy has a centralised server where each user gets a dashboard online to read their power usage. Originally we planned to have these dashboards hosted inside each building on simple servers. Our first prototype simply used a small PC, our IO range and simple sensors. The PC logged the data and also hosted the dashboard.
It seemed sensible at the time. It seemed easier to have one device both logging data and providing a website. A locally hosted dashboard would ensure a nice fast connection between the user and the dashboard. We found ourselves a nice cheap low power PC and created a nice blend of custom software and great open-source technology. The custom part was a sensor-polling database stuffing daemon. This plan let us develop rapidly and we planned to take it to market.
These cheap PCs each need a power supply, case and hard disk drive. Once the hardware is in place we then spend hours setting up a reliable software configuration and installing it onto each PC. But it soon became apparent that this was going to get annoying, fast. With this system we open ourselves up to the possibility of 3rd party reliability issues. Most cheap PC owners expect to reboot often, but we wanted uptime measured in weeks. I shudder to think how difficult it would be to maintain 1000 PCs in the field. Think of all the failing hard drives.
Also it turns out low power computers are not as green as we thought. These little power hogs would sit there 24/7 chewing up the very power we are trying to save. We also had a performance problem. Our clients expect a very fast response in their web browser, but they use that interface extremely infrequently. In that 0.1% of the time they are waiting for their dashboard to load they want the very best performance. Computers that excel in bringing so much data together in a short time require expensive, power hungry hardware. Our compromise between good performance, low cost, low power and high reliability was not going to end well.
To get performance we need a fast box. That immediately ruled out cheap and low power.
So we centralised the data processing and dashboard aspects of Gridspy into http://your.gridspy.co.nz. Now the Nexus takes the place of the PC in each house. The Nexus is a little box that streams sensor readings live from your house to your dashboard. The Nexus has much lower power hardware than the web server because it doesn’t have to do processing “on demand”. Each Nexus draws around 1-2W, a normal PC 150-400W and a powerful web server 500W or more. Since the dashboard sits outside of the users’ premises on a shared web server its real power use per user is minimal.
Our little box has a lot of advantages over the in house PC/dashboard combo. It is easy for us to assemble and program without the complexities of shifting consumer hardware and 3rd party software installs. It has a comparatively low cost, especially as we move into mass manufacture (I look forward to passing that saving on). As there are no moving parts or major heat sources it could be installed in a sealed box inside a hostile, vibrating environment and survive. It integrates the entire system onto a single board, it is silent, it’s easy to install, and it is discreet (especially compared to a locally hosted PC!). An online dashboard is a huge win for both our customers and for us.
There are lots of advantages to us when we serve our dashboard to clients online. Chief among them is the lack of an installation step. We totally control the hardware that serves the site. We can poke, prod and customise the data collected, and we can analyse it in great depth. This also means that we can roll out a dashboard improvement or bug-fix to all our customers nearly instantly.
A central server also lets us centralise all that expensive hardware so that every individual request is served quickly but the server doesn’t spend all day standing idle. I have to admit that I get quite excited when I imagine a server performing well under load - requests flying in, processing going on and insightful data flowing out.
For the client monitoring power use it is much easier for the novice to turn a Nexus on and then visit http://your.gridspy.co.nz than it is to type in something like http://192.168.5.1. This is especially so if you bookmarked the dashboard when you purchased your Nexus. Only the ‘most hardcore’ computer geek (yes: you, me and all our friends) could successfully route an internal IP address to the wider world so it could be accessed from your mobile phone. By comparison the online dashboard is easy to find and access on any device.
So, Gridspy is the power monitoring solution that just works. It’s just plug (and get online) and go.
Further reading:
- Real-time data from sensors to browsers - more about the website
- Introducing the Nexus - more about the device
- Where does all the power go? - why you should monitor power
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