Black Hot Glue?

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.

A Regal Find

As if to coincide with the Royal Wedding, Saturday’s car boot yielded this super-cute Crown (SWIDT) CRP-418 portable cassette recorder!

It’s a great little thing, slightly bigger than a Sony Walkman but outwardly in good condition. Inwardly there’s a world of corrosion, the slide-out battery pack contains what were once four AA batteries.

It does have a 6v DC power socket, but although there was some whirring when I plugged in its vital signs were absent. This must have been a pretty handy thing back in the early 70s, and the tape that was in it contained some authentic dictations recorded with the built-in microphone you can see on top.

This is going to make a great project for a later date. Because of the period the external case is all-metal and screwed together, so it’ll dismantle without trouble. Also it’s the ideal size, plenty of space inside for a full-size Raspberry Pi and maybe even a couple of HATs and a battery. A portable internet radio using the original 3.5mm headphone socket and controls would be awesome, or staying closer to the original it could be a digital recording machine, maybe using a USB sound card to connect the original microphone, performing some speech to text conversion.


A Historical Pointer

Just imagine – It’s the 1970s, you’ve just returned from your first package holiday and the neighbours are assembled in your front parlour to sit through your slide show. The fondue is flowing. But how are you going to point out your hotel room or that dog in the background that stole your calamari? Use a bamboo cane like an animal?

Thankfully Boots has you covered, with their “brilliant light arrow” projecting Screen Pointer!

Another find from Beccles antique market, this piece of 70s culture set me back a modest £1.50. It’s basically just a torch with an arrow filter and a focus mechanism. I’m not sure how well or even if it works as the connections are corroded and the bulb long blown, but it could make a really interesting and practical conversion.

Using AA or coin cells instead of the original SP11 (C Cell) batteries would leave lots of room to manoeuvre inside, and the bulb could be replaced with a super-bright LED, a COB (Chip on Board) LED from a modern torch or even a laser, using the original switch to power it on.

The Game: LCD Shutters

I picked up these LCD shutters a while back from Pimoroni, essentially because they were a new product and I was sure I could use them in a future project.

As they say on the Pimoroni product description:

Essentially single pixel LCD displays, these panels polarise and go black (completely opaque) when you pass 3V through them, and then de-polarise (become transparent) when pulled low or shorted. Easy!

You can treat the LCD shutter like a low value capacitor. Once energised, they will hold their polarised/opaque state, but slowly leak charge over time and become de-polarised/transparent again

The shutters were really well packaged (as you’d hope for something so fragile) and had a clear plastic protector on both sides, which is handy as you’ll handle them a lot.

As you can see in the GIF they go completely opaque when you attach 3v, then slowly become clear again (unless you pull down or short the connections). They don’t seem too fussy about polarity.

This week I finally nailed the concept for using them in a new Raspberry Pi project, which I’m calling “The Game” for now – a long way to go but there’ll be regular updates here and a YouTube video of the whole build when it’s finished.

Begging for Conversion

When rummaging around for old tech at sales some unloved pieces just leap out at you and beg to be upgraded, like this old intercom phone we found at Beccles antique market at the weekend.

It’s a fairly standard old phone, but with a grille where you’d expect the rotary dial to be! The stallholder thought it was originally from an RAF base and it does have that vaguely military / industrial look to it.

It cost around £7, hard to say exactly as I bundled it with some vintage Babycham merch for the Progress Bar. What really appealed to me was how easily this phone could be converted using the Google AIY Voice Kit – it has a grille for the speaker, a built-in button and even a translucent red lens for the indicator LED. Couple of drill holes for the microphones and that’d be it.

With minimal work this could be turned into a unique and practical voice assistant. Most of the work would be on the cosmetics, it’s obviously been exposed while someone’s been decorating as it’s absolutely covered in tiny flecks of white paint.

It’ll clean up though, and with a lick of paint for that grille it will make an attractive bedside voice assistant – especially useful for those weekend “bring me a cup of coffee” broadcasts to the kids.

Weekend Gala

Fantastic weather for the car boot this weekend, I went with several things in mind and found the first one almost straightaway, a pocket transistor radio, £1.

Harvard’s not a huge brand but it’s a really nice little unit – no FM option so without an external aerial. I’ve been after something similar for a while, they have a great look and come apart easily (this one just clips closed). Not much to discover online about it, all I could really find were similar radios for sale, in a range of colours.

The plan is to build something small and functional in the case, as ever keeping true to the spirit of the original. I’m really enjoying playing with the Pimoroni Phat DAC and Phat Beat at the moment, small amplifier boards for the Pi. I think they’d fit really well – in fact the tuning dial on this radio is ideally placed to display the LED VU meter on Phat Beat.

So far I know I want it to play audio – I’m leaning towards making it an internet radio with presets for my favourite stations, or maybe a podcast player or airplay speaker. To stay true to the original it should really be portable as well, but adding in power to the case may make fitting everything in a bit tight. A voice assistant would be another option, but I’m pretty tied to a Pi Zero with the size and they run best on a full size board.

Sunday Concert Boy

Terrible weather over the weekend, the car boot consisted of a veg stall and a coffee van. Still there are Old Tech bargains in other places, and Gumtree came up trumps with this lovely 1975 Grundig “Concert Boy 1100” radio.

It was a steal at £5, but much bigger in real life than I’d anticipated from the photos.

For a 40+ year old radio it’s in amazing condition, but nervously plugging it in out of curiosity was shocking – in a good way.

The sound quality of this thing is just amazing. It has a really full and rich sound, like a valve radio. My father always lamented getting rid of his Grundig RadioGram and I can see why if it sounded like this, I was genuinely surprised and impressed.

Before picking it up I was wondering what I could build into the case, or how I could re-use those lovely tactile slide controls, but now I know how it sounds it’s 100% safe from the screwdriver. I even may put up a new shelf in the bathroom for it.

Let your Heat Shrink dangle!

If you’re a maker in the UK and don’t live in a cave you’ll know that Maplin is in the final throes of its closing down sale right now. The tech press have been quick to negatively compare the sale prices with online deals but there really have been some bargains in store for the price-conscious tinkerer.

One deal I took advantage of is heat shrink tubing, 70% off. It’s wonderful stuff, both for insulating soldered connections and keeping project wiring nice and tidy. The problem is storage – it can be an unruly beast and refuses to stay neatly coiled once it’s out of its bag.

Even worse if you store it too close to your soldering iron it can shrink away all by itself before you can use it!


A top way to keep it both tidy and handy is to let it dangle – I cable-tied mine together at the top, then looped the strands over a convenient light fitting. The tubes are held straight by clip-on tablecloth weights (from Tiger).

As well as keeping it within easy reach and looking cool the dangling strands give you a nice visual guide for how much you have left.

Walkman Phones

It’s always good to hit the car boot as early as possible, last week we got there while some sellers were still setting up – and it was worth it, I picked up these sweet Sony Walkman headphones (MDR-3l2) for just £1.

Amazingly they not only work but sound great and are surprisingly comfortable. They shipped with the iconic Walkman TPS-L2 back in the very early 1980s – the first portable cassette player.

There are clues to this heritage in the design – for example the cable is a whopping two metres long (try untangling THAT) reflecting how previously you’d be tied to a static player and would need a long cable to avoid throttling yourself taking a sip of tea.

Headphones are one of my favourite things to pick up at sales, they’re super-easy to test before you buy and even 45 year old cans like my go-to Wharfedale DD1s are still practical and comfortable to use today. I can’t wait to kick back in a deckchair with these retro Sonys if the good weather ever arrives.