So, I’ve been planning another model railway.
So, I decided to build a Pi based ZX Spectrum emulator, inside a ZX Spectrum case. Celebrating 40 years of the Spectrum and all that…
Down on the old Preston Dock site there is an unusual little engine shed, which was built for Preston Borough Council (long before they became City) in 1985. In 1986 it won The Brick Development Association’s Structural Brickwork Award. It looks like this:
Some years ago, I decided that I wasn’t completely happy with having to carry printed timetables, or having to scroll though big PDF files while chasing Trams on my visits to the Blackpool Tramway.
I figured that it would be better to be able to access the timetables on my phone. As I was incapable of creating Apps for both the Android and iPhone platforms (seriously, have you seen what you have to do to become a developer for iOS?), I decided to do it as a mobile-friendly formatted web page. How hard could it be?
Everyone needs storage boxes for their bits and bobs of electronic dohickery. You can probably buy something suitable from Amazon, but the chances are that you will have suitable items already in your house.
Apps such as Garageband on the iPhone allow you to record your guitar noodling and play about with various effects. But first you need to get the guitar connected to the ‘phone.
Looking about on t’internet, there are loads of instructions on how to build a guitar interface for the iPhone, but most involve butchering existing cables.
As the cost of the required AV cables is stupidly high, I decided to just buy the bits and have a go at making one from scratch.
So, lets have a look at what we need:
A 3.5mm 4-pole jack – plugs in to the phone
A 3.5mm stereo socket (case mountable) – for headphones
A 1/4″ mono socket (case mountable) – for the guitar input
Some 3 core shielded audio cable. Sadly, Maplin fucked up and sent me 2 metres of the wrong cable, despite them looking totally dissimilar and having completely different catalogue numbers.
Anyway, sod Maplin, I’m prototyping here. I’ll make do with bits from my wires box.
The first thing to do is solder the cable on to the horrendously fiddly 4-pole plug. Get the most difficult thing done first, that’s my philosophy.
The pin out for the plug now looks like this:
- Green – (Input)
- Yellow – (Ground)
- Orange – (Output Right)
- Red – (Output Left)
Wrap it all up in the casing that came with the plug, and get a “pigtail” lead:
Originally I wanted this lead to be about four inches longer, but this will have to do for the moment. (You can insert a joke here if you really want).
Next, solder up the stereo socket. I went for the same colour code for Ground/Outputs.
Finally, solder-wise, its time to connect up the socket for the guitar input.
Following the same colours from above:
And here it all, all breadboarded up for testing:
After buying a small case, I discovered it was too small to mount the 1/4″ mono socket in, so I had to look about for an alternative.
I haven’t found anything handy yet, but you get the gist.
An old 35mm film container prooved to be the best case I could find. So, now it looks like this:
So now I’ve bought the Camera Module for the Raspberry Pi. I got mine from Amazon, mainly as I was putting in a big order and was drunk enough to tag it on to the end.
Getting the damn thing set up and streaming video through a web page was a Pain In The Arse,