Posts Tagged 'shdc'


SHDC#9 gave us a suprising amount of activity, in contrast to the general procrastination of #8. So, lets get started…

Jonny brought along an impressive collection of Psion 5’s (and an Oscilloscope he managed to aquire! Great work!). It seems they come to him to die. Apparently most die because the flex cable between the screen and base breaks.

Psion, Anyone?

We all spent a lot of time admiring the design; the Psion 5 keyboard and mechanism is just awesome. So why didn’t Psion do that well? The story appears to be that the products were too good, so no one upgraded!

The keyboard got pulled apart, again revealing some nice design. His plan is to reverse engingeer it to the point of being able to make it in to a USB or Bluetooth keyboard. I can see why; it really is one of the nicest small form factor keyboards i’ve ever tried.

I got to work trying to fix the remaining problems left over from my previous attempts to Bring Back the Big Trak. The main thing was that only half the keyboard was working, which was due to one of the traces on the flex connector having been corroded away. These things seem to be the casue of lots of problems!

Big Trak keyboard connector fix

The fix I used was to draw a new trace using a Conductive Pen. Not the most easy thing to use (you end up dabbing a lot rather than drawing), but it does the trick. Behold, the Big Trak is Back!

Leif brought along his new toy, a Beagleboard, which he was setting up to be accessibly over a serial terminal as there was no appropriate monitor around.


I then got interested in ways of providing remote access to it, so started looking around at VNC implementations. The thing I wanted to find out was whether there were any Java based VNC clients to allow it to be done as an applet from the clients perspective. Turns out there are! I tried RealVNC first, but couldn’t get it working straight away, so tried TightVNC. This gave much better results. The laptop on the right is running the server, and the left is the Java client:

Sweet. Now we just need to get TightVNC up on the Beagleboard!

Somehow during general tools talk and other fix-the-world discussions, ENSO and Quicksilver came up. These are basically applications designed to help invoke stuff from the keyboard quickly. ENSO was the one I tested out; one key feature is it’s ability to calculate the result of an expression that is highlighted, and replace it with the answer. Interestingly, it takes over and is invoked by holding down CAPSLOCK. Makes you realise how you never use that key, and it usually only features as an annoyance when you hit it by mistake!

It is an interesting thing to play with, and it certainly shows how easy it can be made to get to what you want. Emilio even wrote an ENSO Python Extension Wrapper for it. I’ll be trying out Quicksilver on the Mac too.

In another random discussion about something, Jonny mentioned the concept of “Bookmarklets”. These are bookmarks in your browser that are actually Javascript that is run. That means go to any page, click the link and the Javascript is invoked on that page. Now it is obvious these have been around a while with things like digg/blog this etc, but i’d never really come across them or thought about them. A really good example of it in use is Shared Copy. I can see these Bookmarklets have some great potential applications, and i’m sure there are some that haven’t been thought of yet.

The downside is the bookmark field itself naturally limits the amount of Javascript. As an experiment I did a little “Hello World!” Bookmarklet, but made it such that it just dynamically loads a script from a remote URL (script loading has no problems with cross-site urls). This means you can write the bookmarklet just as a .js file on the web, with no size limitations. I put it up at Hello World! Bookmarklet Example; go have a look!

Henry brought his new Bluetooth modules along that he had got from Round Solutions (ordered by fax!). The modules were BlueNiceCom IV based on the National LMX9830.

The main task appeared to be breaking it out to make it useable (bluetack it upside-down to something and solder on wires), then deciphering the datasheet to understand how to make it play. Getting the conections and config are easy when you know how, but they certainly appeared to make it hard to know how. But once it was responding, we had it pairing and talking to a mobile phone in no time. Even sending a text message. Check it out!

And by 2am, we were all wrapped up; not bad for a days work! I think the cake helped.

See you all at the next SHDC!

SHDC#5 – So many projects. Not enough time!

So given the time we had…

Lyndsay introduced us to Lumileds; ultra-ultra-bright white LEDs that can sink up to 1A (and melt apparently), and are being used for lighting such as in her SenseBulb project.

Leif got his priorities right and got us around to Tescos to stock up on obscure beer and even more obscure energy drinks. There was also a mention of pizza, but we never got around to it; I think this is a lesson for the future, and next time we should get the food planned out early! He was working on getting a CrystalFontz display talking. I’ll let what is planned for it unfold over time as it’s pretty awesome!


Rob got to work on his pimped up bike again. The current point of investigation seems to be how to build an Anemometer. Leif happened to have a computer fan with him, and we noted motherboards can now control fan speed. But guessing it was closed loop, a quick google showed us they actually output a signal so you can detect how fast they are going. So feed that in to a micro instead and don’t power the fan…

Tom‘s activities defined what I think SHDC should be about. Come along with great pre-planned intentions of what you’re going to do (very important), but throw that out the window as soon as some other impulse project sparks your interest. In this case, the culprit was my LEGO Mindstorms kit.

This is an amazing piece of work based on Theo Jansen’s walking machines. Tom was a bit limited by the amount of lego available, so a great result! As he put it, Organic enough to feel sorry for it!

My project for the day was trying to come up with a way to do transparent PCBs. I’d been inspired by the Hypnocube, a cube of LEDs achieving some interesting visualisation. Their approach is a load of wires in all dimensions, but I started wondering about if you could just use a stack of clear PCBs. But that obviously meant coming up with how to do clear PCBs first…

There were two main ideas I tried (although a third slipped in on the way!).

1) Draw it…

I got hold of some conductive paint and conductive ink, and a simple glass clip frame. And the result…

Conductive ink test

It works! Although the pen didn’t really draw that well so not convinced the idea of attaching it to a plotter would really work. Maybe if the ink was put in to something that let it flow better.

2) Etch it….

This one came out a discussion with another Simon the day before. Mirrors are usually backed with silver, and Ferric Chloride can be used to etch silver. You can probably guess the rest…

Paint stripped, tracks drawn

Take a £1 Asda vanity mirror, remove from case, try a few chemicals to remove the backing paint, fail, try a blowtorch, confirm that getting glass hot does indeed make it crack, go back to chemicals and rub a little harder (the winning combination was Nitromors and a kitchen scourer, although it did take off some of the silver too). Draw on some tracks with a etch resistant marker, and then etch…

Result of etching the mirror!

Pretty cool! It turns out the resistance is pretty high, so I ended up looking for “more power!”. This is the (pretty poor) result with my 16v laptop power supply…

Etched mirror test

3) A late entry, Steal it…

In a slight moment of inspiration/madness, I ripped apart a touchscreen having convinced myself it must be conductive as they are based on resistance (basically it’s two surfaces that touch where you press, and you can work out the position by taking two potential-divider-like readings, hence they must be conductive to some degree). I may be one touchscreen down, but…

Touchscreen material test

So a pretty successful set of experiments from my point of view! The transparent PCB is a small step closer.

We even found some time to play with one of my other impulse purchases of the day, Polymorph. It’s plastic you can mould in hot water and seemed to work very well, so i’m sure it’ll be cropping up again!

So a great SHDC and a great reminder of how much fun doing little projects can be. But also, as a book that also made it along put so well…

So many projects, not enough time!

So many projects. Not enough time!

So remember to join the SHDC Google Group if you want to make sure your pet project gets some time.

SHDC#4 – I sense a theme…

SHDC#4 seemed to have a lot to do with sensing forces.

Rob was suffering from a fractured elbow as a result of a bike accident. But as they say, the best thing to do is get back on so he was working on his plans to pimp up his bike with pretty much every sensor you can imagine. He was still able to use a tablet PC to sketch out various ideas for measuring air and wind speed. I love drawing diagrams by hand so am very jealous of it! Next time you need a diagram in some document, try the pen, paper and scanner route over visio/powerpoint.

Henry bought us cake and novely beers, and got in to the force sensing thing too. I had some FlexiForce sensors lying about which we started to look at for another monitoring idea. They seemed interesting but measuring 1 dimension didn’t seem to cut it. So a google or so later our eyes were opened to the existence of 6-axis force sensors! So the plan is to get hold of something like that and see if we can get anything useful out of it.

FlexiForce and 6-Axis Sensors

My task for the afternoon was to try out an accelerometer. They are really popular now so easy to get hold of, and I love the fact you can use them to determine orientation (thanks Newton!). So my idea was to mock up a little tilt based interface. So I hooked up an LCD and an accelerometer:

Tip and Touch LCD

My first test app just moved a horizontal and vertical line at a speed based on the tilt direction; this seemed to work fine.

I then thought i’d try something a little more interesting, and basically simulate the lines having mass/momentum (i.e. move to the tilt controlling acceleration rather than speed). With a few tweaks to the multipliers and maximums, this seemed to work quite nicely too. My final touch was to allow you to hold the lines with a finger (i.e. zero their speed).

Mixing a touchscreen and accelerometer makes for a pretty intuative interface.

Good stuff! I’ll aim for the next SHDC around the end of january (maybe Sat 26th January? – check SHDC group to keep track).

SHDC#3 – Rust, anyone…

SHDC#3 was the biggest turn out yet (5!)

Interestingly however, it was probably also the least productive in terms of actual hacking ;o) I think Tom summed it up as a need to come along having scratched the surface of something, or at least have a good idea of what you want to achieve. It doesn’t matter if this goes out the window as soon as you see what someone else is doing and drop everything to join in.

My excuse was jetlag, but really the lack of a clear challenge led to the procrastination. A lesson for next time!

There were some interesting discussions about geek stuff in general, like ways to simplify tracking movement of a person using the constraints of their skeleton. Putting cameras on a persons limbs was an interesting concept. And we discovered a self-replicating rapid prototyping machine called RepRap.

We did end up on YouTube watching this excellent video:

So with lessons learned about procrastination avoidance measures, maybe Oct 27th or Nov 3rd for SHDC#4?

Mobile RFID!

So I had to finish it properly! Here is a totally mobile setup…

Mobile RFID Tx

What we have here is the mbed listening out for id tags using an RFID reader. On detecting one, it then uses the bluetooth/mobile combo to send the name of the person in a text message to another mobile phone. So wave a card nearby and a few seconds later…

Mobile RFID Rx

And all battery powered! I’d forgotten how fun doing this kind of stuff can be!


On Saturday I put on the second SuperHappyDevClub; the sun was out so we setup camp in the garden.

We moved from two peope to three this time! First was a guy called Tom who works at Moviestorm, which is some sort of game/sim for creating your own movies. I’d never met him before so that was great. Turns out he’s done some pretty interesting research in to algorithmic creation of realistic cityscapes, so obviously google earth conversations came up pretty quick, and wondering whether you could recreate all the cities around the world by extracting the characteristic parameters from small samples. Later Rob joined us, who strangely enough also does some work at ARM on mobile graphics stuff. He has an interesting project to pimp up his bike with seemingly as many sensors as he can get his hands on.

My project for the day was to see what I could do with a Bluetooth module I’d got hold of. The dev-board has an RS232 connector which I very quickly realised wasn’t compatible with my no-RS232 laptop. So a trip to maplin with £20 (what?! only because i was desparate!) successfully got me a USB-RS232 interface. It also didn’t work. This made the £20 seem an even more interesting price point to choose. An hour of googling later, it still wouldn’t install. That’s the feeling of productivity we’re striving for!

I shifted over to using a bluetooth dongle instead to see what could be done, and started trying to connect to mobile phones. It didn’t take too long to be able to make a connection, and then Tom caught the bug. So talking to mobile phones became the challenge.

Rob wanted to run a backlight module from PWM, but didn’t know how it was meant to be driven. Obvious answer; pull off the back of the phone and measure it wih an oscilloscope. Obvious problem; no oscilloscope. Obvious solution; build one! So Rob started beavering away on a text readout oscilloscope!

Tom and Rob hacking hard in to the night!

Some hours later and we had the phones doing lots of stuff; it turns out a lot can be done using AT commands over a bluetooth serial conection. Things like getting the phone to ring a number, send us what buttons are being pressed, status information and even access to the text message store.

Rob got his oscilloscope working pretty well. If only we’d had a screen lying around it could have been graphicalised; so that’s going on the shopping list.

So we could now control the phones over bluetooth, but I really wanted to make the bluetooth module work (that was my goal for the day). So I ended up just bypassing the dev-board and wiring the module straight to a microcontroller. That worked much better and it didn’t take too long to be able to talk to it. Interestingly, my first experiment was to use the micro to build a USB-RS232 adaptor, which worked first time! £20 is really looking steep now.

Sending SMS from a microcontroller using Bluetooth and a Mobile Phone!

I finished the night with the microcontroller using the bluetooth module to make a connection and pair with a mobile phone. Absolutely no PC involved, just a micro and bluetooth module, so it could be battery powered too!

And of course, because the micro could now control the phone, at some early hour in the morning this is what my friend Chris received on his mobile:

Hello World! from a bluetooth and mobile phone enabled mbed board!

Microcontrollers sending text messages. Sweet! Now any device can notify you by text message!

If you are interested in joining us next time, see SuperHappyDevClub!

SuperHappyDevClub #1 a (small) success!

Having been really pleased to find an interesting venue for hosting a SHDC, it quickly became apparent that actually organising it with the venue was going to be tough. It has a lot of potential, especially if some of the ideas for it can be implemented, but at the moment it just isn’t setup to arrange bookings. So I decided after a month of trying to accept defeat on this one, at least for now…

So at short notice I decided to put one on at my house; so short infact that most people were away :o). But a guy called Henry was up for it so yesterday afternoon we sat in my garden, drank beer, ate cake and hacked with some stuff.

I had a go trying to do something with a GPS module i’d just got hold of. Here’s what I ended up with:

Wireless GPS Transmitter

A wireless GPS transmitter! And here you can see the output from the receiver:

GPS Receiver Output

I got Henry to walk around the garden with the Tx, and it definitely changed the output in the right direction when he walked north. Pretty sweet!

It was nice to have a BBQ and fridge to hand, so I actually like the idea of a house hosted SHDC event now. So I’ll think about holding another one sometime soon on Sat 25th August. Join the SHDC Google Group if you want to hear more.