Wednesday, February 24, 2016

Accurately measure the speed of (toy) cars in a track

A couple of months ago my friend Chris told me over a beer the problems he was having with accurately measuring the speed of a toy car over a track for a STEM project. At that time I was (and still am) looking for excuses to be involved in some technology fun outside of work. So not knowing much about possible sensors, I theorised with him that an Arduino could do a good job at measuring the speed rather accurately.

After some short research, I concluded that the so called beam-break sensors (i.e. a pair of sensors formed by an IR LED and an IR photo-transistor as a receiver) would probably be the best way to implement this. I also added a LCD to the mix so that the speed could be displayed straight away. The picture below roughly explains the idea.

For the demonstrator I used an Arduino UNO, a couple of beam-brake sensors for Adafruit, a cheap LCD board, a couple of breadboards and a few jumper wires. I actually didn't use the battery pack, but you can use 4 AAA rechargeable Ni-MH batteries to provide roughly the 5 volts required for the sensors, so that you don't have so pass so many wires from one side to the other side of the track.

The HW setup is rather simple. First connect the ground and power from the Arduino to the breadboard for a common bus. Connect the 4 sensors there. One sensor of each pair (the receiver) also need a digital pin so that we can tell if the beam has been broken or not.

The LCD is a bit more complicated. Apart from  power and ground, it needs 6 digital pins to work. We just need to make sure that these pins are connected to the right places in the LCD board. The pins in the LCD board that require connection are shown in the figure below, labelled as 'D7 to D4' and 'D9 & D8' . These are 6 consecutive pins starting from the 5th pin in the top-left corner (i.e. the 5th pin starting from the top-left corner is D4, the next downwards is D5, and so on). The reason why there seems to be a gap between pins D7 and D8 is because there is a gap in the physical pin of the LCD board (so it can slot on top of the Arduino pins). The A0 pin is used to drive the buttons of the board and should be connected to an analog pin in the Arduino.

In terms of SW, we need to use the LiquidCrystal library to drive the LCD, and make sure that we initialise the pins to the right ones, as connected to the Arduino.  We also need to set the digital pins of the sensors as INPUT, and turn on the internal pullup resistor to make sure the default value is HIGH, i.e. beam not broken. After setup(), in the loop section, we need to:

  • Read the status of the data pins of the beam-break sensors, to see if they have been broken or not.
  • If the were broken, record the time at which it happened (using millis()).
  • If the breaking of the beams happened in the right order, calculate the speed (for this, we obviously need to know the distance between both pairs of sensors).
  • Output our calculation to the LCD.
  • Output our calculation to the serial port (for debugging).
  • Prepare the variables to run the 'loop' section again

I won't put all the code here, so I leave it as an exercise for the reader. It is not a difficult job if you have some experience with the Arduino. I do have a full user guide which I might upload at some point. 

Happy Hacking.

Friday, February 10, 2012

BT nonsense with VPN

I might be shooting on my foot for talking too soon, but I have just spent half an hour talking with the customer service of BT about why my BT Infinity connection won't work with VPN. After talking to numerous people that had to talk to their supervisors because they had no idea what I was talking about, I ended up speaking to a sales guy. He said that if I want VPN support, I had to change to a business package and end up paying more than double what I'm paying now, which is over £50 per month. That would include an static IP address (which is a nice addition, but honestly, I don't care about it at the moment). The thing is that it used to work before, but they didn't care when I said this. They just said that BT home does not support VPN. End of discussion.

This is all my fault for not doing my research before calling BT, although one would think that they should know better than anybody else about what's possible and what is not. Of course they don't, because after a brief search I found a BT forum in which they (as in customers, not BT) suggested to enable "port clamping" in the BT hub's settings. Sure enough, there is a menu called VPN, where it is suggested to enable this setting if you are having problems with VPN, which I had. Oh magic... now it works with no problem whatsoever... well, that is so far, because apparently it is unsupported according to their own sales department.

Lesson 1: Always do your research before talking to anybody
Lesson 2: Do not think that customer support knows what they are talking about
Lesson 3: For God's sake, do not believe sales people!

I'm tempted to send a letter of complain telling them that they should have known about the BT Hub option and that it almost seems they were just trying to make more money out of me... but I think I will pass just in case they decide to cut my VPN and say "We told you it wasn't supported". Shame on you, BT...

Thursday, January 19, 2012

Status report on the Internet of Things

Almost two years ago I wrote about the Internet of Things and what, in my view, the IoT did not encompass. In that post I argued that because nobody could really tell what the IoT was, it could be a good idea to start by discussing what it wasn't. There were mixed opinions, of course. My intention was to try to focus the discussion on the IoT a bit and try to avoid falling into the buzzword black hole. But two years down the line, how has the IoT discussion evolved? Has the community gained any focus or has it all finally spiralled out of... well, that, focus.

As you probably sense, my answer is going to be the second one. The last couple of years have seen an increase in conferences, books and journals dedicated to the Internet of Things. This is great, until you realise that most of these are just using the IoT as a buzzword just because is “in fashion”. Consequently, the majority of the papers submitted to these conferences and journals are written by researchers that have not changed their research topic, but they have just added “Internet of Things” to the titles of their papers to be able to publish in more places. Of course, since the conferences and journals had been set up in the first place just to attract more submissions, there is no real filtering on the suitability of the topics and anything with the IoT name on it will be deemed as within the scope. When these papers get eventually published, they send the signal that any topic remotely based to networking and the Internet is valid, and this contamination just goes on an on.

Basically, in my point of view we have seen little or no improvement in the understanding of what is the IoT, what are its implications and how it will actually work. I haven't found any publication talking about how the architecture of the IoT should be, what are its challenges, how can it be achieved or how far we are from it. Yes, there have been some papers describing enabling technologies and applications, but that doesn't really help without a generic, structured vision (and eventual agreement) in how all should fit together. At the same time I have not found much criticism on what is happening... it would almost seem that nobody wants to kill the golden egg hen. Of course, eventually all the research labelled now as IoT will jump to a new buzzword if it is convenient, stick to the old buzzwords if necessary, or none at all if that gives it better chances to be published / funded.

The Future Internet (or the future of the Internet, just to keep avoiding buzzwords) is of course still relevant, and research will inevitably carry on because it is a hugely important ICT area. One could argue that irrespectively of the community going somewhere with the IoT or not, research will continue in a very similar, if not identical, way. As argued earlier, the fact that research in this area has only changed the title of its publications when the IoT discussion became trendy, tells us that the popularity of the IoT will come and go without any major impact in research investment. So, if this is the case, will we then get to the same place regardless of how the research is labelled? Well, yes, but the path is also important. Eventually, the concepts that the IoT encompasses (whichever they are) will happen anyway, but a focus on a structured vision of the IoT would allow us to enjoy results earlier and better. For that reason it is sad to see how the grand vision of the Internet of Things becomes adulterated and diluted over time. Is it perhaps too late for the IoT? I think it is, but I would like to be wrong.

Tuesday, August 9, 2011

Things I learnt with ESXi

I have been using a Vmware server at work to run virtual machines. The server (2.1) is running on one of our Kubuntu boxes. I never liked the Web Access for it, and the whole thing seems buggy and some times just doesn't work properly. Anyway, I decided to give a go to ESXi (4.1), which is another free product from Vmware. Basically its a linux-based distribution which is optimized to run virtual machines. You install it as you would install you regular Linux distro. I did it from a CD that you can download from Vmware we pages. You will need to create an account first.

Direct control over the ESXi box once installed is very limited. You can change some things like the password and network access, but full control is intended to be achieved by using the Vmware vSphere Client. Unfortunately, the client only works in Windows, and furthermore there is no Web Access for the free ESXi. Some things to think about before installing it I suppose.

The first thing you might want to do is to create a virtual machine or import one. In my case, I have installed two so far: one imported from the vmware server that I'm already running, and the other one from Bitnami, which gives free virtual appliances (virtual machines) with specific pieces of software already installed. In both cases, the easiest way to deploy your VM to the new ESXi is using the vmware converter, which luckily runs also on Linux. It will allow you not only to convert VM formats, but also to import and deploy VM from a one server to the other. It will even handle the case when your VM is running. The converter software can independently run in a different machine than your VM servers.

Once you have deployed your VMs to ESXi, you surely will want to back them up. Free vmware products do not have fancy back up support, but for some of them, the guys from the vmware community have been nice enough to provide command line scripts. On the Vmware server, I had my backup set up so I would manually stop the VM, rsync them with my NAS, and start them again when the syncing is finished. For that I used the vmrun utility from the vmware server 2.1 and set up the script as a cron job. Not very intuitive, but after some trying it worked all right. Something like this:
  • sudo vmrun -T server -h -u user -p password suspend "[standard] machineName/machineName.vmx"
  • rsync -a --password-file=/etc/rsyncd.scrt /var/lib/vmware user@IP_of_NAS::volume_name
  • sudo vmrun -T server -h -u user -p password start "[standard] machineName/machineName.vmx"
The ESXi, unfortunately, is not running a standard Linux distribution, and also does not support the same commands as the vmware server, so I can not use the same method. After some digging, there is a script called ghettoVCB which basically does the same thing and more. The trouble is that you need access to the console of the ESXi server for that. To enable that, you need to enable what they call Tech Support Mode (TSM) like here. You can now follow the instructions in the ghettoVCB web site to configure and back up your VM. A few highlights:
  • To backup through NFS, you need to add an NFS data storage to your ESXi server using the vSphere client. Once you do that, make sure that you point your configuration files to there.
  • Once you manually test that your configuration works, don't forget to set up a cron job as explained in the same web page.
  • You will need to install vmware tools on your VMs so the script can stop your VM before starting the backup. If your host is Ubuntu, make sure you read this for doing that.

Monday, August 30, 2010

Installing Linux without CD, Floppy Disk or USB

Recently I got hold of a laptop without a CD or floppy drive, and which BIOS wouldn't boot from USB (is a pretty old laptop). I wanted to install Linux on it, so what were my options? Well, so far I have come across two options:

1. Network Install

If the laptop's BIOS can boot from the internal NIC (network card), you can set up a DHCP and TFTP server and do a netboot. This will load the installer's image from your server at laptop's boot time. There are many guides out there on how to do this, but the one I followed is this one. Substitute Etch for your distribution. I installed Debian Lenny.
The HOWTO is quite self-explanatory. Perhaps one thing worth mentioning is that I decided to create a private network with a different network switch rather than using my regular wireless home router. I did this because I didn't want to stop the DHCP server from the router while I was doing the installation, because I had other machines running using the Internet. If you are also doing this, remember to 1) assign a static IP to your DHCP server so you can configure the server itself properly (I used, obviously the same as the TFTP server and also the default gateway) and so your server can start properly (otherwise it will probably fail or complaint about something when you try to start it from /etc/init.d) and 2) once your laptop has boot from the network card, plug your network card to the actual router so it can install via the Internet.

2. Set up the image from an existing operating system

If you already have Linux or Windows installed in the laptop, you can set up a boot loader so it will boot the installer image from the hard disk instead of retrieving it from the TFTP server. I have tried this with Grub and when you have Linux installed, it is quite straight forward because the boot loader is already installed: you just need to put the installer image on your hard dish and modify the Grub menu so it will show an option to boot from that image. This small tutorial gives you a flavor of how to do both from Linux and Windows. Just skip the boot.ini part if you are doing it from Linux.

Happy installation!

Monday, March 22, 2010

What the Internet of Things is NOT

The “Internet of Things” is a very popular term that many mention but few seem to exactly know what is about. Is one of those buzzwords that are gaining momentum and that walk the line, still uncertain if they will reach the other side. As a good buzzword, the IoT is rather abstract, and aside conceptual definitions, it is very hard to tell exactly what the Internet of Things is. Is because of that that rather than talking about what the IoT is, I will talk about what the IoT is not. With some luck, that will narrow down the scope for a more focused discussion in the future.

The IoT is not ubiquitous/pervasive computing

As if Weiser wouldn't have been referenced enough since he predicted the second wave of computing (4925 times according to Google, and counting), some seem to use interchangeably the IoT and the ubiquitous computing concepts. Although the miniaturization of computing devices and the ubiquitous services derived from their data is probably a requirement for the IoT, pervasive computing is NOT the Internet of Things. Ubiquitous computing doesn't imply the use of objects, nor it requires an Internet infrastructure. The miniaturized devices that Weiser envisioned could represent anything, and provide data for anything. And of course, in 1991, there was little Internet to go around, and although it could have formed part of the ubiquitous computing vision, I don't think it could be argued that global network connectivity was ever a requirement for that vision.

The IoT is not the Internet Protocol

The Internet as we know it can be used globally because clients and servers use the same protocol for communication: the Internet Protocol (IP). It therefore appears logical that the Internet of Things must also run the IP (since is the same Internet, some might say), and that all the new clients to this extended Internet, the “things”, must connect to the same network and therefore run the Internet Protocol as well, right? Wrong. Of course, in a perfect world of limitless power on effortlessly miniaturized wireless devices integrated in everyday things, this would be true. But the reality is that the technologies that have the greatest potential, in terms of size and cost, to empower most of the IoT in the short term, can not run the Internet Protocol because they just don't have enough juice to do it. Examples of this are RFID or Wireless Sensor Networks. Some will argue that there are new low power versions of the IP aiming to running on very constrained devices. Acronyms such as 6LowPAN, ROLL or IPSO will surely be mentioned in those arguments. It is true that the IETF and other standardization bodies are making great efforts to reduce the footprint of IPv6 and related protocols, but they are still IP: a passive RFID tag can not run the IP, nor do many wireless sensor nodes based on the low-end hardware specs, which are precisely the cheapest ones and the most likely to become pervasive. What is more, there are already hundreds of millions of RFID tags and wireless sensor nodes out there, not to mention several billion mobile phones (largely without IP capabilities). Is the IoT going to be an elitist group of only IP-capable devices of which existing old or just cheap devices can not be part?

The IoT is not communication technologies

I was recently at a workshop where NEC Europe described LTE as an enabler for the Internet of Things. Be LTE as it may the next generation of cellular networks (with the permission of HSPA+), I have my reservations in that it has anything to do with enabling the IoT. If is about global connectivity, other older cellular technologies, although slower, also provide the same (or more) pervasive connectivity. In any case, the same reasons given for the IP apply, since Internet over cellular networks is implemented nowadays via IP stacks on the cellular modems. A similar reasoning can be applied to many other technologies that some insist in equalling to the Internet of Things. Technologies such as WiFi, Bluetooth, ZigBee / 802.15.4, 18000-7 come to mind. It is obvious that if things are going to be wirelessly connected to the Internet, they are going to need wireless communication technologies, the same way the “regular” Internet needs WAN and LAN connection technologies (e.g Ethernet) to interconnect millions of computers. However, we can not say that those technologies are the Internet, although they certainly might be part of it.

The IoT is not embedded devices

Words such as RFID or wireless sensor networks (WSN) have often been heard when discussing about he Internet of Things. Indeed, visionaries at the Auto-ID centre and other people working on RFID circa the year 2000 appear to be responsible for coining the term. They envisioned what is today the EPCnetwork, a set of distributed Internet resources that gather, filter, store and discover RFID data. Maybe because the term was never formally defined, because the vision has been extended with new technologies, or maybe just because other disciplines have seen on the Internet of Things an opportunity to attract an increasing interest, the IoT has come to mean much more that just networked RFID systems. Furthermore, too many times has RFID been used to describe what the IoT is without painting the back-end information infrastructures into the picture. If something the IoT is certainly not is a bunch of RFID tags attached to objects an read by random RFID readers. Another technology that has recently become popular when describing the IoT are sensor systems in general, and WSN in particular. This equivalence is even more inaccurate, because while RFID systems have at least certain standardized information architectures to which all the Internet community could refer, global WSN infrastructures have never been standardized and many, many times, not even considered. Some may say, however, that global Internet based sensor standards exist, to which I would reply: yes, but they were not built with “things” in mind (i.e they don't have a standardized way for uniquely identifying things!)

The IoT is not the applications

I recently read an article by The Hammersmith Group in which they talk about plants asking to be watered using wireless sensors, wine racks that know which bottles are stored and medicine bottles that issue warning if the medicines are not taken on time. They titled this article “The Internet of things: Networked objects and smart devices”. What we see here is another common misuse of the Internet of Things, very related with the pervasive computing issue described above. Think about somebody using Facebook or Google at the beginning of the 90's to describe what the Internet is. But is worse, because although I'm sure that we agree that Google is not the Internet, at least is well accepted that is an Internet-wide service. All these applications that many are describing as the IoT are just small services on an Internet-like scale. So, not only is absurd to use Internet application and services to describe the Internet itself, but it is even more illogical to refer to small applications that would have no real impact on a global Internet

Saturday, March 13, 2010

Wireless Communication for the Internet of Things

On last Thursday 11 of March, the University of Surrey held an event called "Wireless Communications to Enable the Internet of Things". This event was organized by the Wireless Sensing Interest Group of the Sensors & Instrumentation KTN and the Electronics KTN. The sessions featured the view of industrialist, academics and reports on existing deployments. I attended this event as a researcher from the University of Cambridge.

The event was organized around four sessions. The first session introduced the three main technologies that are considered the future of cellular communications, namely GPRS, 3G and LTE. The first two were introduced by ST Ericsson, and the talk focused on the key considerations for a communication project. It concluded that 2G and 3G networks are now pervasive and will stay for many years, and that they are best suited for environments which do not require massive amounts of data transfer such as machine-to-machine (M2M) applications. The second talk was given by NEC, and introduced LTE as the next generation cellular technology that will enable the Internet of Things. LTE was compared against HSPA+, and some NEC's ICT solutions based on this and other technologies were also presented.

The second session focused on issues in communications and location based services. Two companies presented: Libelium, a Spanish wireless sensor network start-up, and HW Communications, a British company dealing with mobile wireless communications. Libelium compared the 2.4Ghz, 686Mgh and 900Mhz bands for chips running the ZigBee / IEEE 802.15.4. Some test results were presented and the best configurations for each band were outlined. HW communications talked about location services, and the pros and cons of technologies such as cellular network positioning, triangulation and GPS.

The third session presented two implementations of short-range wireless networks. The first implementation, from the company Zarlink semiconductors, dealt with health-care implants and how to solve problems related with wireless communications. A solution based on a double frequency, single antenna implementation was presented, where a 2.4 Ghz link is used to wake up the device and the medical band MICS at 402Mhz is used for data communications. The second implementation was more of an academic introduction to energy storage technologies by Imperial College London.

The fourth and final session focused on solutions for large scale Wireless Sensor Networks. The first talk in this session introduced the implications of embedded devices and the Internet of Things in urban environments. The concept of Web of Things was introduced as hyperlinks given by physical objects, which is somewhat different from what other initiatives understand by Web of Things. The seconds and final talk on this session was about security and key management in Wireless Sensor Networks.

In my opinion, this event brought much about technologies and applications but little about what the Internet of Things is. It is probably not a good idea to put "Internet of Things" in the tittle without defining what is understood by it. Obviously, the event was oriented to the believe that the IoT is the same as ubiquitous computing or similar terms, but I think is quite clear that both concepts should not be same, because otherwise there would be no need for a new term. Most of the talks were useful to understand the advances in technologies and how companies and academia are aligning towards the future of wireless communications, but I gained no new knowledge on how wireless communications are going to enable the IoT, which is the main title of the event. This is not a new feeling for me though, since so many times I am hearing people talking about the IoT when they either don't know what the IoT is or its implications, or they think that is understood that the IoT is a something that everybody knows (when obviously, they don't know or don't agree on the same definition). Therefore this events has reinforced my believe that a globally agreed definition of what the Internet of Things is should be realised, or we will go deeper and deeper in the buzword hole that I talked about a while ago.