First Projects

This is probably a good place to document my first soldering projects. I started all this with an interest in making a Colditz crystal set. I.e. how do you make a crystal set without access to components? I have vague memories of the TV series Colditz where PoWs made a crystal set from a rusty razor blade.

I found a good website with clues on how to do this but they recommended making a proper crystal set first then replacing the components one at a time until it was all home made.

So I bought a pile of components. A germanium diode or two, capacitors, resistors, diodes, wire, the lot. Soon there was copper wiring hanging over the dining room table and The Nipper was very curious.

I managed to get some Portuguese out of the ether despite having only 1 component. I’m not sure the small fortune I spent on further components helped much. But it was fun.

I then attempted to may my own capacitor from tin foil but couldn’t measure it. So I bought a capacitance meter kit from the Internet and welded it all together. It was very groovy, though controversially it came from Israel which was a tough decision. Not sure I’d do that again.

capacitance meter

When I measured my homemade capacitor it was pretty much spot on, but by that time I was on a roll with soldering projects. God knows how much I spent. I now have an AM and FM radios made from kits plus an AM/FM radio I bought from Tesco and pulled apart before reassembling it.

AM Radio kit

FM radio kit

I read recently somewhere that until you open something you don’t really own it. Well I do now.

Next I ripped apart an old mobile phone, extracting the binary dot matrix display and harvesting the vibration motor. I used that with a penny cell battery and a toothbrush head to make.a robot bug for the nipper.

At this point I discovered I won’t throw anything electrical away ever again. Without any expertise I’d become a hardware hacker.

So how to get the LCD working? The Internet has diagrams but do I have the time?

Maker

I’m just about done with my OLED display. I bought it for about £15 a while back for a Raspberry Pi project. It promised to be a great high tech, but cheap[ish] solution for running the Pi near headless with just a two line glow in the dark text display. Useful … for … something.

Anyhoo, I managed to sodder[sic] the thing together and, to cut a long story short, it cracked into life on the Pi’s 5 volt rail. The default message offering a welcome. Brill.

Now, to get other text out of it. For this I needed to program the Pi’s UART to output a nice serial signal … But it is IDLE high whilst the PICAXE is idle low. To make matters worse the Pi is 3.3v logic compared to the PICAXE expecting 5v. Problem? Not for a budding hardware hacker.

Or so I thought. I shoved the signal through a buffer, checked it on my xlabproto’s UART snooper (“hello world” looked good), inverted the signal using a spare NAND gate, jacked it up to 5v using a purchased converter board. Result: nowt. ARSE!

I thought if I could change the PICAXE to IDLE high then all would be well. It’s involves changing one character from ‘N’ to ‘T’. But this required the PICAXE proprietary serial cable. £15+p&p for the USB version. All that to change one character. To hell with that.

I tried using a USB to rs232 cable cobbled with an Rs232 to 3.5mm jack but no joy. Either the thing is broken or requires exactly the right cable. However, it is cheaper to just order an LCD display and ditch this. What a pain. Just because they charge £15 for a £2 cable.

So I’ve been a bit crest fallen as this was my first hack project. I’ve been feeling like giving up. Bit today I remember I’d ripped a mobile phone to bits and extracted the binary dot matrix display. It’s generally reasonably well documented online. Probably a good thing to tinker with. It will be a magnificent achievement if I get it running. But I’d feel more confident if I’d got this lousy OLED working first.

Anyway I’ll try documenting progress here. I know you’re just dying to hear all about it.