Today the boy started asking how radio stations work so we took apart an old in-car FM transmitter and built a little radio station setup around it, all housed in a box we built and painted. Flicking the big switch at the front and talking into the microphone will see Charlie broadcasting his shows around the house and garden.
The idea is to have one of those ‘On Air’ lights (hence the big hole at the front) illuminate when there’s a show going on.
I have always thought transmitting data via an FM frequency would be a creative addition to any project especially if it involved kites. I once came up with the idea to fly a bunch of sensors via kites that would relay the information down on the ground via a low powered FM transmitter. This could then be adapted to broadcast your own recordings should you be at the beach with friends and wanted to broadcast your own radio show to the people below. Rather like this Raspberry Pi project here.
After finding an old in-car FM transmitter I decided to revisit this project and test it out only to find that the range of the things wasn’t very good at all, probably just a few metres. So I set about modifying the FM transmitter to see if I can boost its range somehow.
Now I’m no electronics expert but on opening up the case I think I got the thing figured out, just check the video out for more details.
I took it outside for a bit of a test, making sure it wouldn’t interfere with anything whilst I was playing around with it.
I plotted my position and measured the distance. My simple modification managed a comfortable 200 metres before the signal started to fade or got drowned out with static.
I have a feeling I could further modify the transmitter more to achieve an even greater distance but I don’t really want to push it. This project is just for fun don’t forget so obviously check the laws in your area before experimenting yourself
I burnt my finger whilst cutting the clasp off the back but it covers a nasty scratch on the box (the dangers of taking projects out and about I guess) and that is how the Signalman got its name.
Still loving the handset despite some funny looks when I’m out with it. Today whilst out walking I was able to pick up a couple of old gentlemen talking about building their own radios. I love listening in to snapshots of people’s lives like this. It’s like I’m fishing for good conversations with the Signalman being my net.
I have a rare free hour and as the weather is nice I’m out testing the amateur radio receiver I built. I’m picking up a few voice transmissions clearly and enjoying the conversations. My receiver also picked up its first Morse code transmission too but struggled a little to translate it. More tweaking needed.
I’ve been a big fan of radio for most of my life, especially the ham radio side of things. Luckily nowadays with the wonder that is the internet, there are many convenient ways of listening in to amateur radio transmissions without the need for expensive kit. If you fancy having a go yourself you can download a copy of my beginners guide to Web SDR and amateur radio that gets mentioned in the video below here.
So this week I started on a very exciting project, building a portable listening receiver that hooks into Web SDR setups around the globe. My favourite one of all has to be the one located on the site of an old nuclear bunker here as I find the 2m band is best for picking up voice transmissions.
The idea was to have a nice portable box that you can carry over one shoulder that will allow you to comb the airwaves whilst on the move. I also included a Morse code translator that will decode any Morse that is picked up and display the message on the small LCD. To finish it off I found a retro handset that someone had bought me for a present years ago. I had originally wanted to incorporate an internal speaker inside the box but including the old style handset just seemed an even better idea.
I love this project and I look forward to taking it out and about with me.
There are a great many prototypes that litter my workshop, so I thought it would be a good idea to talk about a few before I reuse their parts. This video is all about an old idea for a drawing machine and how I made a quick model out of Lego to see if the idea would work.
I was wanting to eventually make a larger decorative box made out of wood, whereby people could turn a handle/push a button and the box would draw them a picture on an A5 sheet of paper. I had started planning out a little gear box to change the rotation speeds that would result in more patterns being drawn. Sadly there were other priorities at the time and this project unfortunately got shelved. Still fun to get the brain working on this one though.
I’ve always loved the maths behind tone benders and synthesisers, despite not being musically minded at all. Recently I got my hands on a BBC Microbit and decided to see what I could make it do in terms of tone generation.
Upon start up it selects a series of random notes and repeatedly loops through them. The potentiometers on the front allow you to change the pitch as well as the length of some of the notes in the loop.
In addition to the potentiometers on the front, there are also two buttons at the back that allow you to adjust the temp of all the notes as well as add more notes to the loop.
It’s still very much a work in progress but the current Micro Python code ever can be found here.
After three months of tinkering the arcade cabinet is finally complete and I love the way it has turned out. It started out as an idea and a heap of scrap wood (mainly from an old bed) and I basically made it up as I went along.
Inside there is a tiny Pi Zero running Retropie which means there is a large amount of internal space to play around with if I ever decide to add things like a coin slot. The total cost of the build (minus the screen which is my tv from the bedroom that no longer has a bed – see above) the cabinet build has come it at around the £40 mark which I think is pretty good going. The most expensive elements of the build were the controls and the vinyl covering.
Some people have asked me for the plans but unfortunately I don’t have any, it was all built on the fly. I would like to make another one but I think I need a bit of a break first. Besides, I need to get some practice in beating my son at Street Fighter 2!
The Raspberry Pi powered arcade cabinet is coming on well. Here’s a little video of my current progress with it.