A warm welcome from Old Tech. New Spec. to everyone following links from the May 2018 MagPi magazine!
I was thrilled to be asked to contribute to this month’s upcycling feature, and hope you enjoyed reading it. If you don’t have your copy yet you can download a .pdf from the website or find it in all good newsagents.
In the last post we successfully cut a hole in the TV screen to make space for the siren, so the next step is to secure it in place and make a translucent filter for the screen.
First though fitting that siren – as luck would have it I had a small metal 90 degree bracket that was exactly the right size to fit between the siren’s mounting bracket and the side of the TV case. The holes needed to be drilled out to hold larger bolts, but with a bit of fiddling it was rock solid.
Next was the screen filter. For this I printed a “TV Snow” image onto an A4 Transparency sheet (the kind you’d use in old-school overhead projectors) and then trimmed it around the existing screen with a craft knife. With everything test-fitted together I placed the assembly in front of the Pi prototype rig so that the Unicorn pHAT would shine through the screen. It looked just the way I had hoped, lots of indirect light and a bit of a glow to the screen, which will hopefully look even better when the inside of the TV is painted white.
Next time we’ll be moving on to the remote and the rabbit ears.
Exciting news! We’ve been accepted to have a Show & Tell stall at the Raspberry Fields event on 30 June / 1 July. More details to follow, but we’re hoping to bring along a selection of Old Tech. New Spec. projects, and hopefully “The Game” if it’s finished in time.
Raspberry Fields is a brand-new event led by the Raspberry Pi Foundation with lots of help from our community of young people, educators, hobbyists, and tech enthusiasts. It will be a chance for people of all ages and skill levels to have a go at getting creative with tech, as well as a celebration of all that our digital makers have already learnt and achieved, whether through taking part in Code Clubs, CoderDojos, or Raspberry Jams, or through trying our resources at home.
It promises to be a great couple of days, come find us and say hello if you’re attending, there’ll be stickers!
With the TV dismantled the next stage is to start fitting the other parts together, firstly the siren. The siren needs to poke through the TV screen, so the first order of business was to cut a hole for it.
Initially I thought of using a hole saw, but the screen is so bendy and fragile I had a feeling that would end in disaster. I decided to use the Dremel to nibble through the plastic, later using a sanding attachment to clean up the hole.
It all went really well, all limbs and digits are still intact and the hole is both the right size and neatly cut. It fits perfectly over the siren, and test-fitted together with the TV it’s really starting to take shape.
Next on the list is fitting the siren permanently in place, and sorting out some kind of translucent image for the screen, one that will display the different lights controlled by the Raspberry Pi but not let you see all the way inside the TV
The YouTube channel is finally ready for business, Subscribe now for your regular fix of #Retro meets @Raspberry_Pi!
I’m hoping to publish a regular monthly project video with Retro-Spectives and New Spec Reviews in between. The monthly video will cover all the stages of a project in detail so you’ll be able to follow along and give some of your Old Tech a New Spec!
The next stage in the “Game” project is to prepare the portable TV for its new function. Dismantling is always one of the most fun parts of a new project as you never know what to expect when cracking something open for the first time.
This teardown went really well, four screws to remove and a few snips with the wire cutters left just the outer shell, which is the bit we need. There’s also a convenient earphone socket left over that we’ll eventually use to plug in the LCD Glasses.
Now that the TV is in bits the next thing is to very carefully cut a hole in the plastic screen to hold one of the most critical parts of the game – the siren. Once that’s done we can start figuring out where all of the other parts will go, and how it will actually work.
No old tech finds at the car boot over the bank holiday weekend, but something even better – a modelmakers vice. This thing is brilliant, it clamps onto the workbench making it easy to move around, and swivels all over thanks to a ball joint in the base.
Best of all its jaw opens wide enough to hold a full-size Raspberry Pi – not that I’d often grip a Pi in there but sometimes full-size HATs need some kind of soldering and it’ll be great for that.
It’s quite an old one, no visible brand but really well built, the lever brake applies smoothly to the ball joint when you have your angle selected, and it’s held rock solid. It also has a cool if slightly perished rubber gasket around the ball joint that reminds me of old car gearsticks.
Up to now I’ve been using a small suction vice when soldering, but that sucker has never really worked reliably and it tends to skate about on the bench. This is a definite upgrade and only set me back £4.
This slightly toasty early 80s cassette player was picked up alongside the Crown recorder at Saturday’s car boot – £5 for both (bundlemania as the kids call it).
As usual I plugged it in out of curiosity and stone me it worked, though the pitch varies a bit, probably a worn out belt in there somewhere. I was fascinated to listen to the tape that was left in the Crown portable player, it contained some music taped off Radio Norfolk (paused at just the right points when the DJ piped up) but also some dictations from what I firmly believe to be a gas appliance salesman.
I’ve not had a working cassette player for a while and I’m really enjoying digging out our old mix tapes, from the days when we’d keep a stack in the glovebox of the car.
The sound quality can’t compare to the likes of Spotify of course, but for background music in the workshop it’s a tactile and fitting addition. I think it’s safe from the screwdriver (for now).
The Game is coming together, using the fancy new black hot glue I’ve now added the LCD shutters to a pair of old shades for testing.
They’re now fully wired up to a 3.5mm stereo jack plug and cable, which clips into a socket connected to the Pi’s GPIO. The gif above shows the shades turning opaque and clear based on a Python script.
The shutters are working well, the GPIO control pulls them from clear to dark instantly, so far I’ve tested intervals as short as 0.3 seconds with no problems.
They really mess with your vision when wearing them (which is the entire point!) but the shades make the whole experience a bit darker than I’d hoped – mind you I’ve only tested them in the workshop so far, which is a bit dim.
What’s The Game all about? Keep your eyes on future posts! The next stage is dismantling a 1980s portable TV.
I’m just going to say this – black hot glue sticks are a thing, who knew?
I was browsing the RS Components website for Sugru last week and found this instead, I can’t believe I’ve lived without it for so long.
Normally I don’t use hot glue much as it’s a bit unsightly, but the black sticks work really well, are extra-long and leave a nice glossy finish (as long as you don’t mess with it while it’s cooling).
I’ve already used it several times in the workshop, to tidily fix the cracked plastic case of an old TV and to secure the LCD Shutters to the shades for The Game. And obviously to fix beer mats to the ceiling above the Progress Bar.