Should I buy wireless headphones?

Well… no.

 

I really wanted to have wireless headphones for running and gym visits, so I got myself a pair of Skull Candy SMOKIN’ BUDS 2 WIRELESS. Those headphones sound good enough for exercise – on par with in-ear headphones I used so far (Sony from Xperia Z and Z3 and Skull Candy buds).

But I’m not happy with the purchase. Here’s why:

  • The wireless headphones need charging. I’ve already run out of power once in the gym. And even if you have power the headphones tell you they need  charging soon by… beeping. Beep… beep… beep… every few seconds. Try to concentrate with that in your ears.
  • The headphones are not wireless. There’s no wire to connect to the phone, but there’s quite a lot of wire connecting the in-ear buds. And this wire is more annoying that a standard cable, because it’s not attached to a fixed point, so it bounces around neck. And it has a sizeable bit of plastic in the middle. Skull Candy tried to patch this by adding a quite heavy rubbery neck bundle. Which stills bounces a bit and is no less irritating.
  • Android 6 cannot reliable handle BT audio. I’m using BT audio in my car, with Sony SRS-X55 speaker and with those headphones. Switching between Sony speaker, car and SB2 sometimes confuses Android. I had to go to BT settings to remove the connection and reconnect the phone again to all those devices several times. It doesn’t always help – I had to restart my phone three times as well. Which is not what I want to be doing in gym’s changing room!
  • BT range is good in theory, but seems to have gaps. Maybe my phone (Xperia z3) has a directional antenna or maybe it’s the headphones. I can leave the phone 3 to 5 meters from me and the sound is working well, but as soon as I slip the phone into my pocket the sounds starts to break. Not much, but I’m getting very short breaks every few steps – just like my body is blocking the signal.

Would I buy different headphones instead of SB2? No. The whole approach is broken and the whole ecosystem needs updating. I’ll try again in 3 years.

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[solved] Mac OS X PPTP VPN connects, but not forward traffic goes through

Most hotel wifis are open, so to secure my connections I’ve set up myself a PPTP VPN using QNAS TS-453A box (btw. great machine, get one!) to tunnel all my traffic via encrypted connection.

Windows 10 and Android are connecting to the VPN and the traffic goes smoothly, but my Mac OS X El Captain caused me quite a bit of grief – it connected to the VPN without a problem, the internal connections were working great, but the forwarding traffic got stuck. Ping was working fine, but WWW did not. Some initial parts of first website were loading and then the connection got stuck.

Cause:

The issue was caused by MTU mismatch. It seems that NAT on VPN server adds some headers, which cause the packet to be to big and get rejected.

Solution:

Go to apple->system preferences->network-><your connection>->advanced->hardware and set MTU to Custom with packet size 1400 instead of default 1500. You may want to experiment to find maximum MTU value that works for you.

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Bandit the Quadcopter crashed / useless prop guards

And so I crashed today. I flew too far, lost orientation and decided for a firm landing instead of flying away into unknown. I’m glad I haven’t put cameras on this time.

Just last week I have installed the Diatone 5025 Propeller Guards. They looked nice and the green/red colours LEDs helped with orientation during hoovering, but not in flight. I’ve installed them to match DJI Phantom – red in front and green on the back, but I found them more confusing than helpful. Anyway – they lasted exactly one crash. The propellers indeed didn’t break, but one of them got bent. So the guards haven’t delivered on their promise. I paid £15 for them for which I could 8 full sets of propellers. Don’t buy them.

Now back to the workshop :)

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My First Quadcopter Build – Parts and Tools Checklist

 

 

Let’s start with something exciting – the final result! Say hallo to Bandit the Quad!DSC_1750

 

Building the Bandit was a lot of fun, but also a bit of frustration when I kept discovering I needed more things. Below you will find my final checklist.

 

Bill of materials

  • Frame. I used Emax 250 Nighthawk Pro Frame made from carbon fibre. 250 is a size class. It is supposed to mean that the distance between opposite motors is 250mm, but in reality the size is 280mm. Close enough I suppose. This size is comfortable to build and not scary to flight.
  • Motors. I used MT2204 2300KV outrunners. Two of them with clockwise nuts and two with counter-clockwise, which should keep the propellers steady.
  • Flight controller (FC). I used CC3D – small, open source based controller. It is inexpensive and has a very decent software helping to set it up.
  • Electronic Speed Controller (ESC). I used Emax 12A. The brushless motors require alternating inputs on three wires to spin. ESC is a component that translates PWM impulses from the flight controller to inputs for a motor. Those are smarter than they look – they are microcontroller based and their software can be updated. Mine use SimonK firmware, which seems to be a standard in this class of quads. Mine ESC have BEC (Battery Elimination Circuit), which provides power to the Flight Controller.
  • Propellers. I used 6×3 carbon fiber props. I do not like them – they look cheap and have scratched edges straight out of the box. Also the carbon fibre is very tough, so in case of unavoidable crash the motor may be hurt more that with a plastic prop which would just snap. On the other hand some say the carbon fiber props give less vibrations. I’ll probably will be changing them.
  • Radio transmitter (TX). I used Spektrum DX5e because I happened to have one. I like it – it feels good in hand and Spektrum is recognized as a good quality brand of RC.
  • Radio receiver (RX). This is a crucial component – it needs to work well with your transmitter and with the flight controller. I opted for Spektrum AR610 – one of the simplest and cheapest in line. It uses PWM communication with the controller, which is fine for now.
  • Power Distribution Board (PDB). In Quadcopters there are two almost separate set of electric systems: low current signals (RC-FC-ESC) and high current power to motors via ESC. PDB helps with the latter. You may use PDB or you can make the harness using wires (14AWG should be enough). PDB leaves exposed contacts which may lead to short-circuits, but it is easier to assemble than the harness. You choose.
  • Battery plug. I own few batteries with XT60 plugs, so I used the same in my quad. I bought one already soldered to a piece of 14AWG wire.
  • 14AWG wires to connect the battery plug with PDB.
  • Battery. I used 2100MAh 3S LiPo from DJI Phantom. Most people recommend smaller and lighter ones around 1300MAh 3S.
  • LiPo Battery charger. Self explanatory
  • Mini USB cable. The flight controller needs to be set up from a computer. CC3D uses mini usb, not micro as phones do.
  • Battery straps. You need to fix the battery to the quad somehow. I used two velcro straps.
  • Heat Shrink. There’s quite a lot of things to solder and isolate. Heat shrink is much safer and looks better than isolation tape.
  • Cable ties. There are a lot of wires in the finished quadcopter and the frame offers no help in hiding them. My receiver does not offer any mounting holes, so I used the cable tie to fix it as well.  I used few of 100x2mm and some of 150x3mm cable ties.
  • LiPo Charging bag. Rarely the LiPo batteries can cause violent fires. LiPo charging bags contains the most of the flames. Grab a bag, they are worth it.
  • Crocodile clips (see tips and tricks)

 

Tools

  • Soldering iron and solder. You will need to solder the motors, ESC, PDB/harness and a battery plug. I used 30W iron and I felt it was to small for the power cables.
  • Helping hand/3rd hand tool – you want the wires as short as possible, which means the soldering is harder than usual. Without the helping hand tool from Maplin I would be sitting here until next Christmas.
  • Heat gun. I didn’t feel using a cigarette lighter would be good for the machine. Heat gun is the cleanest way to shrink the shrink wrap. Go PRO and buy one!
  • Cable cutters
  • Screwdrivers
  • Hex keys
  • Small spanners for the frame and propeller nuts. I used pliers instead.
  • Computer with internet access.
  • Multimeter – to check for the soldering work before connecting a real battery.

 

Tips and Tricks

  • ECS and motors have three wires with no information how to connect them. I soldered the middle wires together and then connected the remaining ones using crocodile clips in a random order. This allowed me to check the rotation direction of the motors before committing the proper joint. I happened to choose wrong order on 3 motors! You will check the rotation direction while setting up the machine in Open Pilot software.
  • It is extremely easy to scratch the carbon fibre with any sharp tools. I have made circles around few bolts where I used pliers instead of a correct spanner.
  • You can get a pack of 75 cable ties in three sizes for a £1 in Poundland. You want to have different sizes, so you would spend £5 in B&Q and £9 in Maplin to get them. And you will end up with many unused ties.
  • If you haven’t soldered the 14awg wires before practice it on a side before starting the real thing. I found this to be the hardest part.
  • Remember you put the shrink wrap before soldering ;)

 

The build took me two evenings after I have gathered all parts.

 

And now it is time to fly!

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Cancel Virgin Media Broadband after installation

Background: My BT Infinity 2 gives me speeds around 37Mbps only, so I decided to try Virgin’s XXL Broadband 152Mbps. The installation was smooth and first speed check run after installation at noon shown 160Mbps. Wow! As I quickly learnt timing of the test was crucial – the Virgin infrastructure can’t gets congested around 6pm. On most of the days the actual speed around 7pm was between 30 to 80 Mbps, but on Sunday it dropped to 11Mbps. What’s worse the pings were quite unstable, up to a point that response time was noticeable on Ajax based websites (like facebook). Torrent downloads weren’t that great either even during the day – I tried to download Debian .iso and uTorrent never shown more than 50Mbps, so I suspect some kind of traffic management, which I do not like. All in all we decided to cancel Virgin and stay with BT.

 

Cooling off period vs Virgin Media

Virgin doesn’t want you to cancel and they play tricks to make you give up and stay with them. When you join you get a paper letter titled “Your right to cancel before installation”. The last line of the letter says “If your new Virgin Media service(s) have been installed  within 14 days from the day after you placed your order, you can no longer make a cancellation under this policy.”. I’ve googled a bit and they say the same everywhere.

“Crap” I thought…

But then I remembered that there is a EU rule saying that we have a right to cancel any contract bought on-line in 14 days (more info here), so I gave Virgin a call. The friendly guy on the other side of the phone listened to me and redirected me to “customer relationship specialist” who offered to lower the price to £31 (from £41 – great deal!). I declined and when I used “cooling off period” phrease he agreed to cancel my contract without any fees – basically he agreed to obey a law. The call took less than 10 minutes.

Where’s the catch?

I’m not a lawyer, but I think Virgin’s catch is in the last few words of the letter they send – “under this policy”. Yes, you can’t cancel under this policy, but there’s a law above it that says you can (not under THIS policy though). That’s a nasty trick. Shame on you Virgin for hiding the information!

Can I pay less, please?

£31 Virgin offered was a better price and I thought BT may be flexible as well. I called them and told them I want to stay with them, but Virgin is cheaper. The guy spent 30 seconds clicking and came with a special discount of £6.15 a month – £73.8 a year for a another 10 minute call. Fair deal to me!

Appeal to British folks

I understand this is against your nature, but get the phone, call your providers and demand your rights or at least lower prices!

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My first half-marathon trial

Few weeks back I made a decision to complete a half-marathon this year. I set up myself a realistic goal of completing the distance of 13.1 miles (21 km) in less than 3h. For regular runners it may not seem fast, but for an obese IT pro guy it is.

Yesterday I decided to do a trial run to see how it feels. I have never before tried to keep required pace for more than 9.5 miles. And… I succeeded!

Here are few thoughts I had on my way:
* good podcast helps, but it should not be anything important. I do not really remember last 40 min of what I heard.
* using food supplements and sugary drinks helps. The body does not refuse to go further when filled with carbohydrates. In the past I tried walking just on a water and my body just stopped moving along the way.
* good socks matter. I was stupid to wear a pair of this socks and my right foot hurts today! My feet started to hurt about halfway. I knew that they will hurt a lot when I finish, but I was able to tell myself to deal with it. Don’t be sissy, push it!
* I kept controlling time all the way. Endomondo help by saying updates every mile. Calculating the remaining distance, checking required pace and estimated arrival time helped to take my mind of the walk itself, which I found quite helpful.
* At 2h15min I have made less that 10 miles which caused me to panic a bit. I had to make a decision – move slowly and miss my 3h target (with option to beat it in the next attept) or push more to make it. I decided to push and my 12th mile was fastest of them all with time 11m1sec!
* London is a multicultural, but quite segregated place. It’s fascinating how quickly it changes.
** I’ve started in quite traditional olde english area
** I quickly moved to a rural park
** Next area was inhabited mostly by Africans
** Then followed a patch of multicultural rich people with few Bentleys on driveways
** A mile down the route Asian and Middle East communities dominated the view – with Mosques, Arabic and Hindu centres
** Last bit of the way was “new urban” with people of all origins, but without much traditional look of any kind

See more details about my route on endomondo site:

And one more interesting view showing time of each mile I walked:

Btw: in September I will doing the half marathon in support of the Shine Walk to support Cancer Research UK. I’m collecting money to support their hard work and so far I got £197 out of my £250 target.

Please support me if you can!

Big thank you to those who support me!

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JustHost shared service – standard vs pro

Our new jewellery store is hosted on JustHost.com. I owned the a standard shared server for couple of years now and it was doing it’s job. My static pages were served, email was working fine. Until we started doing something serious…

We tried to run Harry Fay for a week before I realized it is terribly underperforming. I got used to response times around 2s (total page load 7s), but I failed to observe that quite frequently server needed much more time to produce a result – up to 38 seconds! I’ve spend half a day before contacting tech support, which said “it won’t work, but a Pro account or VPS”. I didn’t want to manage the full box, so I choose Pro account.

What are the differences between standard and pro shared server on justhost.com? Well, the Pro hosting seems to work. Both machines were 32 cores, 32GB of ram, but the standard server was overbooked. On standard machine vmstat was showing 35-50 processes waiting at any given time, while on the pro server I see between 0 and 15. Memory usage is also healthier on Pro hosting – I’ve seen minimum of 6GB free while the standard hosting was swapping. Average response time is down to 600ms (compared to 2100ms) and I haven’t noticed any choking.

My general feeling is that the standard shared hosting on just host is not worth it’s price if you want to use it for anything more that static webpage of your kittens. The tech support is generally accessible and will deal with small issues quickly. The answer for bigger issues is: pay more.

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