November 30, 2020

Problem with your internet security

So I am aware of this scam because I have heard it before, but not everyone has. If you are familiar with the scam you are less likely to be caught by it. Also the scammer's cost is their time. I talked to them for 21 minutes and 30 seconds before I got bored.

09:36 The call starts with a recorded message (female voice, Australian accent) saying it is Telstra, and your IP address has had its security system compromised. Press 1 to talk to a technician.

Your internet service provider won't cold call you with a recorded message. Also I'm not a Telstra customer. This is the first warning that it's not real. They want the call to sound scary and urgent so that you'll do something.

I always dial 1 (unless I'm in a hurry).

09:37 I'm put through to a person with an accent. He launches into a pitch about how he is from Telstra and there is a problem with my security system and my IP address. How do you know the caller is really from Telstra? What if the caller wasn't?

I interrupt to say that I don't know what an IP address is. He says that suspicious traffic was detected coming from my IP. I tell him that I don't know what that means. Is it something to do with intellectual property? Oh it seems this is internet protocol. He wants it to sound technical, so that I'll think he knows what he's talking about. A scam requires you to trust the scammer.

09:38 He asks if my computer is connected to the internet. I play dumb and say that I think I have internet on my phone. He asks if I have a computer. I say yes. He asks if it is connected to the internet. I say I don't know. Scammers depend on you not really understanding.

09:39 He asks if I ever shared my wifi password. I tell him I don't know what that means. This is an effort to improve his credibility. Of course, don't go telling people your wifi password, but if you get hacked, it is most likely because of a virus or trojan installed on your PC, rather than someone using your wifi. At this point he puts me through to his supervisor.

09:40 I tell him that I'm concerned that if my internet is not secure, isn't it risky for me to let him look at stuff? Won't this just help the criminals? He says that these criminals have got into my internet connection. They are "overseas people". Practically it is likely that the scammer is calling from "overseas" where it would make it hard for Australian authorities to prosecute him.

09:42 I repeat my question. If the "overseas people" can get into my internet connection, shouldn't I just shut it down, not grant access to someone who just called me out of the blue. He assures me that we will lay a trap for the "overseas people" and to them, it will seem like my laptop is off.

09:43 He asks if I have a Windows or Apple Mac computer. I say I don't know, but it says "MacBook Pro" on the front. The scam is about trying to install software on my computer so that later they can do things like install ransomware, or steal personal data from me, so they want to know what kind of computer I have so they know how to attack it.

He asks me to open up Safari. I say I don't know what that is.

He asks me to open up Google Chrome. I say I don't know what that is. At this point he asks what I use the computer for. I say to play games, and to write letters to people.

09:45 He says to hover my mouse over the icons. Oh I see Google Chrome now! He says to open it. I say oh it came up with Facebook. Oh yeah I remember. I use this for Facebook.

He explains how to type in a web site www. Yes got that. Team Viewer. Is there a space? Oh no space. Yes OK got it. Now . and c o m. Oh yes .com I have heard of that. Team Viewer is a legitimate site that allows remote support. Scammers get you to run this to give them access to your computer.

09:46 Click enter. OK I read out the site to him. Sounds good. OK click the download link. I said I see "Windows" "Mac" "Line-ux" "Chrome OS". Oh "Chrome" is the one you said before. Should I click on that? No click in Mac it seems.

I said I got an error.

He asks what the error was. I said something about internet security.

He asks me to read it out, but I said sorry I already closed it. I'll need to go back. What was the site again? Team Security?

09:48 I click on the privacy policy link (next to the download link). He asks if the file downloaded. I read out the privacy policy to him. (He is very patient!) I tell him that maybe I clicked wrong.

09:50 I tell him I'm a bit concerned that I'm not actually a Telstra customer. This is a red flag. This should alert me that something is not right. He says that Telstra are the main internet service provider, and all other internet goes through them, so that is normal. Is that true? How could you make sure? You could hang up at this point, and call your internet service provider to double check.

09:52 He tells me that once I install the application it will say it is connected to Telstra's secure server. Think about it. This caller could be anyone. Anyone could make an app that says "You are connected to Telstra's secure server" and it means nothing.

I say I can't see the download (I didn't actually download anything. Don't download stuff that a stranger says to download!) He says to look in the top right corner and see if there is an arrow. I say that the top right corner has the date and time, and it says my batter is 100%. He asks if I see teamviewer.dmg. I say I don't see it.

He says check in the bottom left corner. I say I see icons in the bottom left, and one that looks like the Mac smiley face.

09:55 He says to hold down the control key (and talks me through how to find it). I say OK it's down. He says to press J at the same time. I'm not sure what this is supposed to do, but it doesn't do anything.

09:57 He's still trying to trouble shoot why team viewer didn't download.

I tell him that I need to go now, but that I think his company is dishonest for trying to scam people, and he shouldn't work for them.


August 30, 2020

Configuring Home Assistant for the Aeotec Z-Wave Stick

In theory Home Assistant's native support for Z-Wave is quite good. Plug and play.

In practice, not quite.

Start here of course: https://www.home-assistant.io/docs/z-wave/

Note: Make sure you follow the steps about configuring a network key if you want to add secure devices (which I do).

Home Assistant installs the required Python modules at runtime when you modify your configuration, so in theory there is nothing to install. It's just a bit slower at start up the very first time.

Unfortunately I had problems pretty quickly. The logs show that the openzwave module failed to install.

The solution was to install a required system library that was missing on my Ubuntu server system: libudev-dev. Details at https://community.home-assistant.io/t/aeon-labs-z-stick-gen5-on-hassbian/31687

The next problem, although obvious now, was that my homeassistant user didn't have permission to access the USB device. Add the user to the dialout group, but of course, that only works for new login shells. If Home Assistant runs via systemd, better to just reboot!

Now I see the Z-Wave section in my configuration screen.


If I go in there I only see 1 device (the USB stick). Here is the information screen.


It seems that HA lies about its zwave plus capabilities, and also the baud rate. Anyway, looks good.

The electrician is coming tomorrow morning.

Planning for Home Automation - lighting edition

I'm planning on connecting up the lighting in my flat to my home automation system. At my previous place I was renting, and I had normal BC bulbs, so smart bulbs was a good choice then.

Now that I'm not renting, I have more freedom, but also my lighting uses LED modules, so you can't just screw in a smart bulb. I have decided to go with a Z-Wave solution. It is a wireless solution that uses a mesh network. The standard guarantees compatibility between parts, and also it integrates well with my existing home automation system Home Assistant.

In choosing to go with Z-Wave, compatibility with Home Assistant was important (although it does support most things), as was the ability to have the system operate even if not connected to the internet. Note that Z-Wave is not cheap, but once you exclude solutions that are not approved for connection to Australian mains wiring, some of the cheaper options are ruled out already.

The first step in planning was to look at what lighting circuits I have, and what I need.


I have about 10 lighting circuits in total. A couple of those I won't connect up to home automation, such as the light in my bathroom, and the light in my laundry.

My existing switches are Clipsal C2000 rocker switches. While you can use rocker switches, I am going to swap these out for "bell press" switches.

I have one circuit that has a 2-way switch. One of those switches is next to the front door, and it would be really handy to have an automation rule that lets you use the front door switch to turn off everything. My research showed that common Z-Wave lighting controllers have 2 switch inputs, which would allow you to wire up the 2 existing switches to the same module, and have them do slightly different things.

The next step was to get an electrician. A friend recommended Ryan from It's On. He wanted to come and take a look first, to make sure he was happy that my project would be able to be done to completion. Apart from my 2-way switch concern, I wanted to check that the control modules would fit in the wall cavity (behind the switch). I 3D printed some mock-ups of common brands of controller so we could check. (You can download the designs at https://www.thingiverse.com/thing:4560264 )

All good. Ryan is happy to proceed.

The next step was to order the parts I needed. I ended up going with Oz Smart Things. They are local, and their prices are quite competitive. They have Clipsal bell press switches that match my existing switch plates. I ordered 6 Aeotec dimmers, and 1 Aeotec switch (my balcony light doesn't need dimming). For circuits with less than about 20W of load, Aeotec recommends a dimmer bypass, so I ordered a couple of those for my hallway circuits (that have only 1 x 10W LED module). Also Calum at Oz Smart Things has been really helpful with answering questions.

I'm going to use the Aeotec USB stick connected to my Intel NUC server to control everything. It supports secure devices.


So good when everything arrives!

The next step is to make sure everything works on the software side, so that I don't have any setup issues once we start to install them.



April 25, 2020

Toilet roll roller

This week someone kindly left a box of industrial sized toilet rolls in our building's foyer for people to take. The large size roll isn't going to fit in my bathroom, but maybe I can improvise something. Hey it was free!

My first thought was maybe I can wind some onto an empty roll. Perhaps there is a way to fit the roll to my drill to help wind.






While it looks broadly feasible, the fit is not good enough. Maybe I could make some kind of roll holder that attaches to the drill, and fits inside the cardboard roll to help roll it. At this point I'm thinking of just doing the minimum to get something working.

I have plenty of time at home at the moment, what with COVID-19 and isolation. Captain Over Engineering to the rescue. Why not just 3D print the roll itself, along with an attachment for the drill. I sketched it up to help with my thinking.


Maybe slots in the roll, and some kind of spoke things in the drill attachment. I made a design in OpenSCAD and printed a proof of concept.





It seems broadly feasible. My roll was a bit too thin, but the fit between the parts is good. Not too loose. Time to print the design at full size. A toilet roll is 10cm long, and 4cm in diameter.





With the roll a bit thicker (and so stiffer), the fit was tighter. I needed to sand the joints a bit.

I needed a way to spool the paper off the large roll easily. Luckily I still had some metal piping left over from my towel rail project. Add some chairs, and I'm in business.





Now it's winding time. I wondered how easy it would be to wind consistently. The tension is a bit tricky, but I didn't have any problems with side-to-side movement.





Cut the paper, and I have a bathroom-sized roll.





Now the end cap detaches until I'm ready for my next refill.





If you would like to print one yourself, the STL files (and the OpenSCAD source) are on Thingiverse at https://www.thingiverse.com/thing:4309439

March 09, 2020

Adding a second towel rail in the bathroom

My bathroom only has one towel rail. That's fine when there is only one person living here, but a bit inconvenient when there are two.

The company that makes the bathroom fittings do make a double towel rail, and you could probably get one for around $100. The down side is that they are very hard to find, and also the length is slightly different to the existing one. Once you had paid a tradesperson to tidy up the wall where they removed the old one, it is not going to be a quick job.

Enter the towel rail extension.


This is a bracket that attaches to the existing towel rail and allows you to attach a second one.

First you'll need a second rail that's similar to the first one.

This cost me $5.49 at Bunnings for a 900x19mm rail.

My existing rail is only 600mm so I needed to cut it to fit. This leaves a tube with open ends, so I designed and 3D printed some black end caps.


I worked out the angles and the rough design on paper, and then built it in OpenSCAD. I made the sizes customisable, so if you don't have the exact same diameter of tubing you can easily adjust it. The mock up in OpenSCAD looks like this.


I designed screw holes to put it together, and then I split the bracket into 3 pieces.


There's a piece that rests against the wall to hold the second rail in place. With the first 2 pieces attached it looks like this.


You can see the detail of how it is screwed together.


Now with 2 brackets in place I can fit my second rail and screw on the end pieces.


Works nicely.

If you are interested in making one you can see the design on Thingiverse.

Things I would do differently next time:
  • The angle is still not quite right. Making the wall pieces slightly shorter would work better.
  • I could incorporate an end cap into the bracket itself, rather than making it a ring around the second rail. That makes cutting the second rail to size more tricky though.
  • The bracket fits the existing rail just slightly too loosely. I would probably make it 0.5mm smaller, but it's close enough.