Adventures with Flippy the Flip-dot Display

Considering my next project, I wanted to make an electromechanical display using magnets. I turned to the internet for inspiration and quickly came across Flip-dot displays; solenoid driven pixels. A good starting point for what I wanted to do, I looked further.

I found a 900mm, 56×7 display on eBay from a bus salvager (who know such a thing existed!). The displays used to be common on public transport – prior to being replaced my dot matrix LEDs – to display the route number and destination. It cost me £170, which may seem expensive to some, but for 392 individually mechanically actuated pixels that are quite a feat of engineering, I thought it cheap.

Manufactured by Hanover Displays and with a basic datasheet to hand, I took the plunge. Continue reading Adventures with Flippy the Flip-dot Display

SoundBar VU Meter Laminated Wooden Speaker

I felt that the battery powered Bluetooth speaker I made could be improved with more colour! Taking a leaf from the VU meters on amplifiers of the 80s, I decided it would be neat to sandwich clear acrylic between the plywood layers, each with an integrated LED that would form a full body amplitude meter.

Having a look around, I found a IC made by Texas instruments that did the VU meter job for me: the LM3915. Below is a photo series showing the construction and completed unit. I designed this version as a soundbar to sit below my monitors at work, so it doesn’t have a battery or Bluetooth, making the wiring easier inside and a slimmer unit. For this one I also used an Oak stain rather than a clear stain on the ply and filled the text with black acrylic, which looks much better I think.

HDD Clock

With a cupboard full of old hard drives and some spare time, I recently set about making a persistence of vision clock. Using the platter of a hard disk, a slot is cut to allow backlighting to be emit. When the disk is spinning at 5400rpm+ and backlight constant, the disk appears opaque, as the slit is ‘refreshing’ each point of the revolution faster than our eyes. The trick is to measure the revolution time then flash or change the backlight colour at a fraction of this revolution time at the same point each revolution, in order to create a light segment. For example, flashing the light at a frequency twelve times the disk frequency in phase with the disk will create 12 light segments:

f_{light}=12.f_{disk}=\frac{12}{p_{disk}}

Expanding on this, one can create a light based clock, which takes some getting one’s head around on first sight!

Continue reading HDD Clock

MacBook Core Duo Goes Solid State

Why Replace My 2006 MacBook HDD with SSD

My MacBook is the 2006 original; the white Core Duo 32bit. I got it upon starting University and that ended up taking six years. Amazingly, it is still going strong and whilst I want a nice retina MBP, it would be truly frivolous, given how well this one still runs.

Over the years I have given it a number of upgrades: 70GB > 500GB HDD, 512MB > 2GB (max for Core Duo) ram, new battery and a complimentary top deck from Apple (long story). Now I was turning to an SSD.

Continue reading MacBook Core Duo Goes Solid State

Van GPS Dash Integration

Those little window sucker things for GPSes and cables dangling everywhere get on my tits. Since getting the van, I’ve been intending a dash integration of sorts, whether completely containing a GPS unit, or building a CarPC with my Raspberry Pi, it was put on hold until I had some time. With the race season over and Uni finished, now was the time.

I opted for a neat GPS dock rather than trying to integrate the thing fully. That way, the GPS can be removed for other vehicles and updates. I’ll let the photos do the rest of the talking.

Musical Colours Update

I finally got around to completing my musical colours project:

  1. Make the prototype permanent by building a perfboard arduino.
    Includes the standard 5050 driver and usb to serial connection.

    I wanted to keep the standard 5050 controller for general van lighting, controllable by the IR remote. I did this by using another transistor as a switch for the 12v line into the controller. One of the routines in the code then pushes the gate high to turn the controller on.

  2. Continue reading Musical Colours Update