Saturday 6 August 2016

Wireless 433Mhz home alarm system from ebay

Following on with my faulty alarm problems at home (The X10 system) I've been looking for an alternative, waiting for when the current one acts up enough to warrant buying a replacement.
This week it did just that, making strange noises from the sounder and forgetting the remote fobs. So I decided to look around.
I had a few requirements:

  • wireless (to avoid the need for long wiring runs to the sensors)
  • gsm/remote alerting (to sms or ring me during alarm conditions or let me remotely check status, arm/disarm, etc)
  • keychain/remote arm/disarm (Wife and daughter prefer these to tapping in a code)
  • Interface with my home automation systems (More tricky, but basically have some I/O I can tap into)
  • "nice" appearance. It'll be in a prime location in the house so don't want it to look terrible.
  • Cheap (ish) as I'm a cheap-skate so don't want to spend a lot of money on a solution that I'll never be 100% happy with (I also have a high expectation for electronics, so I'm never happy!)
So after a lot of searching, I found a system that might fit the majority of my requirements, and have the potential for expansion and tinkering. It's also not mega-expensive which gives me more incentive to take a look inside and tinker with it!
The ebay listing I found was this one, so the unit came with the control box (and PSU), 3 door sensors, 3 motion/pir sensors, 1 smoke sensor, two keychain remotes, one additional sounder and an outside bell/sounder box. Not a bad package for the price I feel.

Delivery was in a couple of days, so now I have the unit I've started to play with it. So here are my findings on the unit. Firstly it's not the best plastic casing I've ever encountered. It's distinctly cheap, but rounded corners and smooth edges so it's not going to win a fashion award, but it's also not too hideous to put in your hallway!

This is the main control unit, front. At the front you have the two speaker grills either side (As I found out, one is a microphone and one is a speaker). Behind the clip down door is the push button keypad. At the top you have the LCD screen and a series of LED indicators either side for constant system status.

This is the rear view. You can see the 12v power cable going in, the SIM slot and the various I/O screw terminals. To the left you can see an on/off switch. This worried me slightly immediately when I found it, assuming it would turn the whole system on and off. However as it turns out this is only the battery master switch, normal power was not controlled by this switch!
The screw terminals provide 8 wired inputs (and can take normally open or normally closed with the use of a set of resistors supplied), it also has a sounder +/- terminal, a constant 9v output for supplying alarm boxes, etc. Two GND terminals for the I/O ports, then the final two are COM and NO which I've yet to work out their function or use.

Powering it up for the first time, I found the speaker to be VERY loud, even normal arm/disarm and voice prompts were at a volume unbearable for setting it up. The volume level I suspect was fixed so it always ran at that level, no configuration to set it either which was disappointing. So the first job I'd have to do was change this, as it was almost unusable in this state as soon as it was put up it would annoy me!
So, the back came off and I discovered some very recognisable components inside:

Looking at the board, top left (blue square) is a relay, which I think will be the alarm output switched contact.
Below it is a ZTE cellular modem which supports SMS and telephone calls. The coil to the left of it I think is the internal antenna for it (There is also the on-chip connector for external antenna if you need it). To the right of it is the SIM card (with mine inserted). NOTE: This is 2G only (EDGE/GPRS) so you need to find a mobile company that supports this (So O2, T-Mobile/EE I believe should be OK. Three is NOT an option - I tested this). So the potential here is that this won't work very well, and not for long as mobile networks phase out their 2G networks, so something to be aware of here. However chances are you can just swap the board for a newer equivalent that uses the same AT command set.

Over to the top right (with the yellow outline) is a small backup battery, this probably keeps power to the EEPROM for storage of data, time, system state, etc.
The to the very right of the board (which has the black wire coming out of it) is a very recognisable part! It is a 477Mhz receiver that is commonly used in Arduino and hobby electronics, soldered on as a daughterboard. The black wire is the antenna.
If you then look to the bottom left, you'll see the matching 477Mhz transmitter board with it's own black antenna wire running along the left towards the top. So these two are standard boards that you can buy for Arduino development.
Here are similar modules you can buy easily for Arduino development:

Above the transmitter board is a two-pin connector, this connects to the speaker round the front.
Here is the front of the board:

Here you can see the microphone to the top right (I've flipped the board) and the LCD screen and various status LEDs. You can also see the copper contacts for the buttons.
These may need to be altered as the key button presses aren't very accurate, so probably need some better contacts here which i'll work on another time.

This is the front casing, showing the 8 Ohm 5W speaker and plastic casing and buttons.
So, first job is to reduce the volume output of the speaker. Since it's not used much and doesn't carry high current I'm going to simply wire a resistor in series with one of the leads.

The final soldering and resistor work looks like this:

That was a larger value than I'd wanted to apply (120 ohm) but it should reduce the volume appropriately. I powered it up and it reduced the volume pretty well, perhaps a little low (as it had distorted the spoken voice slightly) but that should do for now (It was the lowest resistor value I had!)

Now onto the 433Mhz sensors. These attached to the doors/windows and had a magnet one side and a reed switch a the other, very simple typical design really, so taking a look inside it:

Top left is the red LED which flashes when triggered. Top right is the 433Mhz transmitter crystal, the spring to the right is the antenna.
The push button is brought to the front of the unit as a press button (This is for setting, to trigger a signal). At the bottom is a 12v battery, and above it is a set of 4 jumper pin positions. I'm assuming these set a unique code for the unit so you can change it if so desired, adding a little more security to your setup. Naturally, no instructions on this! To the left you can see the reed switch soldered in there (and without trimming the excess wire!), so quite a simple design once again.

On the other side of the board is all of the transmitter electronics:

Which I was actually surprised it was so complex, as again this is just a simple 477Mh transmitter when the reed switch was activated. I'll dig into the wiring at some future date.

So there it is, all in all there are good points and bad points. For example, 477Mhz is hobby electronics, so you CAN sniff the traffic and protocols, and no doubt spend enough time to watch the data and decode/decrypt them. But for the average user and average building security this unit will do the job nicely.

I've noted down all the relevant chips I've discovered and looked up so far:

Follow-up to this is HERE:

Wednesday 3 August 2016

BT DSL, FTTC and a rant about BTO engineers

Here we go again, another blog comment about the copper-wires service BT provides and the DSL services on top of them. As most of you know I work for an independent ISP, who are BT wholesale customers. That means we buy in bulk off the carrier (BT Wholesale). BT still maintain the copper pair (wires to your premises), the street cabinet that these copper pairs terminate into and then get patched back to the exchange (Also BT). Once at the exchange they are fed over BT's core network back to their central hubs where we then take a bulk feed off them and service our DSL customers from our own network, IP space, etc.

So, in this case my DSL drops regularly. I'm in a new housing development (2yrs old) which is part of a larger older estate (+10yrs). The rest of the estate cabinets were upgraded to FTTC and were really good quality (I lived in one of the other houses/roads in the same estate and got 80Mb down on FTTC, really good!). But BT and the builders Bellway in their infinite wisdom decided NOT to upgrade the cabinet that's serving a large number of the new houses that were built.

Now this to me isn't an oversight. These buildings were planned for some time as part of the overall estate development. The plans had been in at the council, residents associations, etc, so it was clear this development would take place and would provide a large number of additional houses. In our street there are around 40-50 houses. There are then additional streets, probably 5-10 in number so that makes quite a considerable number of houses.
These are fed from an old, standard BT cabinet. No FTTC. And broadband is VERY poor to this cabinet due to it's copper wiring distance back to the exchange. 1-2Mb is the stated maximum potential speed. It's also not very reliable and drops regularly.

This gets me onto part one of my rant. Why didn't BT and Bellway agree and upgrade this cabinet during the upgrade rollout for the area? It seems there is joint blame here as the building company have a say/input into services from the telcos. (Before anyone asks, no it's not Virgin Media cabled area either as they're not doing any new rollouts at present). BT's continual statement when I press them about it is that the cabinet only services two business premises in their planning, and so wasn't fit for FTTC upgrades. OK, I can see what they're on about, there are two businesses along the same road that have been there for 20+years. So it appears their plans weren't updated, or provided by the builders, or were ignored. Either way these homes are without high speed internet, which to be honest is shocking considering the push for digital futures, etc.

We're probably a more than typical family. We're quite high-tech, all our kids use electronics and the internet. My wife and I use the internet for pretty much everything in our personal and professional lives. I also work from home at times and doing so on a slow connection is tricky, especially with VOIP calls which for the most part work, providing nothing else is happening on the line at the time.

Then there is the terrible stability problems. The line drops quite regularly. At least once per week, and when it drops the speed drops (both the download and upload sync) and quite often becomes more unstable. It seems when the line is at a good sync speed and stable for a long period of time it's fine and usable. As soon as it drops and re-syncs it becomes unstable.
This is my biggest complaint. The fact that when it drops it comes back and has high packet loss (20-30% usually) and then I have to run a BTW KBD to get the thing sync'd back at anything sensible and to stop the packet loss.

I have made a correlation though with when it drops. There is one period on a Sunday morning early hours (between 2am-5am I've noted) that it seems common to do this action. But the other time, is whenever a BT van/engineer is in the cabinet! EVERY TIME they are in the cab our broadband drops momentarily and resyncs with this poor/unusable connection.

This leads me to think that the jumpering in the cabinet is poor, as whenever an engineer is in there it must take the lightest of touch and the cables must move and cause a resync.
I've had numerous engineer callouts that we've arranged through BTW at work, to get this investigated, checked. They've remade the connections, swapped pairs and ultimately give up and just say it's as good as it'll get due to the long distance from the exchange and that it'll always be unstable.

I've also submitted to BT many times the request for FTTC and investigation into feasibility, polled my MP and tried every path I can into trying to get an idea on if/when that cabinet can be upgraded, or if not, why not! And so far I've got nothing. I've got various email communications from BT who repeatedly say it's not on their rollout plan, etc, and so won't go any further.

So come on BT. You're trying to give rural communities FTTC and better broadband. What about a large housing development, in an already converted exchange. Look at where you've deployed and check, did the deployment reach all the locations? Does it do what you want?

Monday 1 August 2016

Halfords Diesel Emissions Cleaner - with results

This is a quick review of the Halfords Diesel Emissions Cleaner from . These are in metal cans that you add to your fuel and will help reduce exhaust emissions, combustion chamber cleaner, cleans fuel system, removes soot deposits and is advised to be used pre-MOT to help ensure your emissions are within legal limits.
Generally it's a cleaner that helps keep your engine running better by cleaning out some of the deposits left on cylinder walls and piston heads due to combustion.

So I'm going to use it on my Chrysler Grand Voyager, 2.8 CRD engine, it's a big 2.8 engine with an automatic gearbox, so not a very efficient engine, and it's pulling around a big 1.5tonne (ish) car too.

I was sceptical, as I know a little about how these work and didn't see that it would make much difference, but at the same time wanted to give them a try and see how I got on.
(I also have the petrol version which I'll test out on my wifes car soon and show the results too)

So, the instructions are wait until you're down to 1/3 of a tank left, add the Halfords Diesel Emissions Cleaner to the tank then drive for a further 20-30 miles before filling up as normal. No need to drive differently, etc, so pretty straight forward.

So to test how it performed, I have my previous car computer miles to the gallon indicator, which before the cleaner was showing up at 28. This is a big diesel people carrier I drive so it doesn't get great fuel economy so let's see how it does!
After driving with the fuel cleaner in for 25 miles, I then got to refuel, so reset the trip counter

Then started to use the car as normal, I had a few town drives and a couple of longer journeys so used up around half a tank again, and at the end was quite impressed! The fuel economy was showing 33.7 which is quite a move up from 28.

A lot more than I was expecting to be honest! So all in all I think this is a good product, it definitely made a difference in this VERY unscientific test (So don't tell me how wrong/flawed my testing was, I know it wasn't scientific!) and to me any sort of improvement on a big old diesel engine like mine is a good thing.

I'll post a full video up soon on my testing and the results so you can see what you think.
Why not try it yourself and tell me how you get on, I'd love to hear back and see your results.

Disclaimer: I received this product in exchange for a fair and unbiased review. The review/opinions above are my own review on this product.

EDIT: Also I've recorded a quick video on this test: