Home-made stylus for capacitive screens

A colleague has bought their partner an iPad for xmas, along with a Wacom Bamboo stylus.  I loved the stylus, and wanted one for my smartphone, but didn't want to pay for it.  A bit of Googling revealed some home-made versions, with an old pen and some damp sponge, but they felt a bit 'bodgy'.  So I thought I'd have a go.

The base for my device is an old tyre pressure gauge I got free with a bike magazine years ago.  It has to be a metal case as the capacitive screen responds to tiny electrical charges from your sweaty fingers.  The nib also needs to be conductive.  I found a bit of conductive foam in the memory-slot hatch of a broken laptop, but you see these little pads everywhere (well, if you dismantle electronic things often enough you do).

The pressure gauge.  Photo taken after I'd butchered the top bit!

The foam pad from an old laptop.  It sat between the chassis and the inside of the memory access flap.  I think it earths the door.  Well, it did until I ripped it out.

 Chop off the top and hoick all this gubbins out

 Tuck the foam pad into the bottom of the spring and shove it back in.  The sticky-out bits make a nice interference fit, plus the remains of the pressure-gauge end make a plug that holds it all together.

This is now the business end.  It needs to be about ½cm square to mimic the tip of your finger, but it works surprisingly well!  I might add a old bolt or similar bit of metal into the tube for a bit of extra weight and the 'real pen' feel.

The finished stylus in action!  Free painting app for Android - Sketchbook Mobile Express.  Next, find a clip and a nice top bit to finish it off!










Nice end plug and protective lid from an old felt-tip pen.  I've also glued in a cut-up allen key for extra weight.  It also now has a pocket clip (not pictured!)

Guitar over Cat5 project 4

Done some testing in a 'real' environment now, and it's a qualified success.  It handles the FX send and return plus the channel control without a problem, even over 10m of cat5.  However the disappointment is that as soon as I add the input from the guitar it squeaks and feeds back like a bastard.  It just about copes over 1.5m but is unreliable over a longer run.  If I had any electronics knowledge at all there'd probably be an explanation.

So I will be using it live, as I hope it'll reduce setup/breakdown times.  Pics of the final setup to follow...

Guitar over Cat5 project 3

The stage end now looks like this:

In a metal box for protection from drunken dancing audience members with uprated jack sockets.

Inside view:

Next week - testing live!

Guitar over Cat5 project 2

Moved into phase 2, here's what I have now:

Basically a Cat5 socket connected to 4 bits of guitar cable with jacks on the end, and;

and a Cat 5 socket connected directly to 4 jack sockets.

Item 1 gets connected to the amp sockets: input, FX send, FX return and footswitch

Item 2 (stage end) connected by short patches to input/output of the pedal, guitar connected to the corresponding input socket.  For my test the amp I used had the wrong type of footswitch (momentary action rather than latching), so I had to plug the actual footswitch into the box.  All I'm really doing here is making an extension cable, but just using the medium of Cat5 rather than multicore!

BUT... the damn thing works!  No apparent crosstalk/interference/line hum/attenuation, even through a 5m patch cable.  I'd call that a success.  Next time, testing it in a proper band environment (rehearsal room)...

Guitar over Cat5 project 1

My stage guitar rig can be a bit of a bind when setting up and breaking down - it's configured thus:

Guitar plugs straight into amp
Effects send to Boss GT8 pedal
Output from GT8 to effects return
Additional cable from GT8 to footswitch allowing GT8 to switch channel

So all in all 4 cables involved.  I wanted to try & cut down, initially by using a 4-pair multicore, then I could bring the guitar input down to the floor, keeping to a single cable run.

But multicore can be a bit expensive, and I'm an IT network technician with access to lots of Cat5 cable, so I started to wonder...  Could I run the whole thing over Cat5 UTP network cable, put a RJ45 socket at either end then all I'd need is a patch cable of the correct length.

No-one as far as I can see on several Googlings has tried it, so the only way to find out is to experiment.


Today I have this:

which is an old guitar lead soldered to one pair of a bit of Cat5, punched down onto a socket module

and this

which is Cat5 cable punched down into a module with a jack plug on the end

Plug in the lead to my guitar, plug the 2nd bit into an amp*, connect with a 5m patch lead and... bingo!  It works!  No apparent loss of signal strength or quality.

*I did use a proper amp to test - the mini-Marshall is just to show schematic!

Next step is to put in the other channels and see if there's any crosstalk, hum or interference with the FX loop running backwards & forwards.  Watch this space.

Fuji S200EXR shutter release self build

I built a shutter release switch for my Fuji S200EXR out of an old mouse.  This is the circuit diagram.  The idea came from this website www.trafficshaper.com, where there's a view of the inside of the RR-80.  As it's only 3 resistors and a couple of switches it was pretty straightforward to build, although it's impossible to find a 2-stage shutter button switch without actually dismantling a camera!

The other difficult bit is getting the Mini-B USB plug.  I got mine as a solderable one from Maplin, but it only connects to the standard 4 USB pins.  The 5th pin is what's required here, so I had to modify the plug, too.

So on my otherwise standard-looking mouse left-click is focus, right-click is shoot.  More details and pictures available if anyone's interested.  Here's a pic of it in action to take a self-portrait with some burly bikers!

 

The next plan is to build in a timer circuit so I can do unattended time-lapse photography.  Watch this space, probably won't happen for months!