Monday, 28 May 2018

Ruxpin Arduino Upgrade


Teddy Ruxpin hacked! He has a motor and potentiometer in his head which were wired to a servo control on his main board. After a bit of trial and error I was able to get the electronics from an old servo connected up so that he can be controlled directly by the Arduino (in this case a Nano) using the servo library.

I'll have him talking soon!

Saturday, 14 April 2018

Electric Vehicle Charger Installation

Okay green energy fans and cheapskates who love getting something cheap, here is my quick guide to getting a home electric vehicle (EV) charging point installed.

First of all you are entitled to a grant of up to £500 against the installation from the Office for Low Energy Vehicles (OLEV), which your installer will process for you. After some research we went for the EO 32-amp charger installed by Baird Electrical and this cost us £250 after the grant was applied. The installation was very straightforward as the charging point is beside the meter box on the outside of our house which itself is on the driveway. The EO charger is the simplest to operate and all that was required in the meter box was a 40-amp RCBO in a separate consumer unit. 

After getting the charging point installed we decided to switch to a Day/Night meter to get half-price electricity at night to charge the car. Our supplier is Airtricity and the night rate in the summer runs from 12:00am until 9:00am which is plenty of time to charge the car even from almost flat (as happened last night). As the only other thing we have that uses a lot of power is the tumble dryer and every lamp in the house is now an LED, we won't be hit too hard by the slightly higher day rate.

The only problem we encountered was Ali running up a £25 cellphone call to Airtricity's office in Dublin because they were supposed to 'phone us and not the other way around. That one is being chalked down to experience as it turned out if you prefix the Irish 'phone number on the '3' network the cost drops to 3p a minute or something, but if you don't it's 50p a minute.

Here's the day and night meter installed which is less than half the size of the old mechanical meter. The only odd thing is that the time is 10 minutes slow, but I'll look into that one.

One last bit of cleverness. When we switched to Airtricity almost 10 years ago we got a free wireless clamp meter which had long gone out of use. I cleaned it up, put a new battery in it and clamped it over the supply to the charging point so that the display in the house will show total electricity used by the car rather than the whole house.

And here is the wireless display inside the house showing power being used during charging. You can see that it is just about 3 kW which is much lower than the 32-amp that the charger is rated for. I think that this may be to do with the charging cable we have after running into a bloke with a Renault Zoe who showed me his wire (fnarr, fnarr) which was a bit thicker than mine (fnarr... stop it!). It turns out the cables are rated 16-amp and 32-amp so that will need to be the next purchase when funds allow, but all good for now.

Saturday, 7 April 2018

Television LED Light Box

Another broken television, this time a slimline 32-inch Bush which had suffered a cracked LCD during a house move. So I took off the LCD panel and dumped that and behind we have 22 high-output LEDs as a backlight. These are 3-volts each and wired in series so that the current can be kept constant and relatively low, which means the power supply has a 66-volt feed out to the backlight. Luckily the power supply is working fine so it was easy to rig a test (always being careful not to electrocute oneself, kids) and even control the light using the power button on the old remote.

It is very bright and looks amazing.

The only downside is where to put the power supply so that it is out of harm's way and earthed because the remnant case is metal. Unfortunately it is just too wide to sit in between the 2 rows of LEDs inside the box, but I'll work on it.

Friday, 6 April 2018

Light Strike Bonus Ninja Find

We've been collecting the last remnants of the Wow-Wee Light Strike series over the last few years because for home laser tag these are great fun.

Unfortunately, the prices on eBay have got completely out of hand and there are very few items left in the UK, so finding this working pistol in the Barnardo's charity shop in Carrickfergus for £1.99 was a stroke of luck. It means we can have a side arm each to go with our pulse rifles when we're playing Starship Troopers!

Sunday, 18 March 2018

In the beginning there was the Word...

In a fit of nostalgia I ordered up 'Making A Transistor Radio' from a second-hand book seller on eBay a couple of weeks ago. This wasn't entirely necessary as the book has been scanned, PDF'd and uploaded several times over the last few years, but I wanted, no, I needed a copy.

Why? Because this is where it all began, my obsession with technology and anything that needs electricity to run.

As some of you are aware my grandfather Bertie Walsh was one of the first radio amateurs in Ireland and had his original licence under Marconi's patents. His callsign was GI4RY and if you Google that you can still find a couple of references and I think a scan of one of his QSL cards. He made his fortune as a cinema magnate in the 1930s and was fascinated by the technology of the time. So I grew up with this wonder for anything connected to radio or television and my earliest memory (aged 3) was the adults (mainly drunk) going mental in July 1969 when a certain man stepped out on a certain moon and said the second most important words of all time (only Sagan's 'Pale Blue Dot' is more important).

So aged 14 borrowed a Ladybird Book called 'Simple Circuits' from the Carnegie Library in Bangor (County Down, Ireland), but then my father bought me 'Making A Transistor Radio' and helped me to do just that. This was no easy process in Northern Ireland in the late 1970s. Belfast was a relatively dangerous place and there was only one electronics store so we ordered parts from a guy called Dennis Brown in Bangor who ran a radio repair shop. It usually took about a month to get the parts and a lot of these were substitutes, but in the end I got there, in part by cannibalising broken radios my dad got from the council dump now that he had taken on the job of stores clerk at the works department after a spell of unemployment (this was the 1970s remember and they were crap).

We got loads of these multiband radios in the early 1980s from the dump. They were actually not bad, but they were in a cardboard case with a dodgy mains input which wouldn't pass any health and safety certification these days. I kept one for a few years that was similar to the one in the photograph because it covered most of the useful VHF frequencies and in those days air traffic, police and fire service transmissions were analogue and plain language which was useful in an urban combat situation. The police callsign in Bangor was 'Golf Bravo.'

The book used a really clever system to construct the circuits using softwood, woodscrews and screw cups to make a sort of early breadboard and it worked really well. So well in fact that I've used the same technique over the years for testing 240-volt circuits so that I can be assured the dangerous voltages are under control.

So that's where it all started and within a year I had borrowed a ZX80, bought a second-hand ZX81 and then went on to the ZX Spectrum, Kempston interface, CB radio ('10-4'), built my own Z80-based micro-box, PC's (286, 386 and so on), PIC microcontrollers, C++. HTML, Java, JavaScript, PHP, CSS, SQL, AJAX, Arduino, Raspberry Pi, Android AppInventor and now I am about to push through into another parallel universe and prove that Dolly really did wear braces in Moonraker. Somewhere.

And I still love cannibalising old radios.

Sunday, 11 March 2018

Samsung Power Supply

I've been fiddling about with a 40" Samsung LCD television today. I was given this free because the power board had packed in. The previous owner had attempted a repair by replacing the 'Bad Caps' (i.e. blown electrolytic capacitors, Google that one!), but the de-soldering and soldering was a bit ropey looking so I tidied that up and replaced 2 of the capacitors myself as one didn't look right and the other was the wrong value. I managed to find a schematic diagram online for the board (Hansol SIP400B), which was helpful in identifying the capacitor values.

Anyway, I put it back in the TV and powered it up and all the voltages coming off the board are correct, but all it does is click. This is the result of a relay on the board switching the circuit from  standby to power on. The red LED on the front panel lights and the set is receiving IR signals from the remote control.

This is really frustrating, but as 95% of these boards suffer from Bad Caps, I might just buy more new ones from CPC (which should only cost about £3) and give it another go. It would be bad to lose such a nice Samsung TV, which I was going to give to the Wee Man to use with his PS4.

Saturday, 13 January 2018

Retro Keypad Find

I was having a clear out and found this homemade keypad. I built this as part of my computing project when I was training to be a teacher in 1989. I used to go up to the Maplin store in Edgeware on the tube to get parts, or Cricklewood Electronics which was like the Old Curiosity Shop. This wasn't cheap either, I had to buy about 20 of the switches with separate caps, but it looked good when it was done with the Letraset transfer letters. The keypad was wired to a Sinclair Spectrum to allow entry of Logo-ish commands to a Lego Technic robot buggy.

Happy days!