There are many options for different chips which could be used in a LED matrix display. But no suitable part existed in a form factor compatible with the LilyPad Arduino (or FLORA) sewable micro controller boards. With this deficiency in mind I began investigating and experimenting with different designs for a new add-on board for use with the LilyPad.

The result of this initial work was two sizes of self-etched prototype boards which I called GPIOPAD’s. At the heart of each board was a I2C GPIO expander chip from NXP, the 8-bit PCA9674 and the 16-bit PCA9675. Using these boards I spent a number of nights in August sewing a basic circular and linear pattern of LED’s and resistors onto the back of a polo shirt. This shirt was part of the wearables projects I brought to World Maker Faire in New York in late September.

After World Maker Faire I took a break from wearables to try and finish off some other projects. But I kept thinking about ways to improve on my prototypes and possible new add-on modules.

In November I came back to this project and made a number of changes to the board which should make them easier to work with. These changes include using a consistent arrangement for the VCC, GND, SCL and SDA pins, adding current limiting resistors to each of the GPIO pins on the board, and using solder jumpers to select different I2C addresses.

With all these changes I decided to come up with a different naming convention for these boards. The new boards I’ve called SEWIO8 and SEWIO16.

I sent an order for about 30 of these new designs to be fabricated by the US based OSH Park batch PCB service, which took just over three weeks to arrive in Ireland after placing the order. The circular boards were supplied after tab routing so I had to clean up the remains of the tabs and mouse bite holes with a file. But I’ve been very happy with the results.

I soldered a couple of each type of board and then began sewing up simple circuits to prove that the board designs worked correctly.

So with my trip to 29th Chaos Communication Congress (29c3) in Hamburg rapidly approaching, I started thinking about what I would do or work on during congress. As I was targeting wearables with my new boards and I hadn’t seen wearable projects begin worked on at congress before, I though doing a practical workshop might be interesting.

So the weekend before Christmas I began looked through the components and materials I had at home and TOG. Using these materials I came up with a simpler sewable circuit with a battery, resistor, LED and switch. Over the weekend I self-etched and solder a sewable PCBs to hold a CR1220 batter and another to hold a momentary push button, and made up lots of fabric pieces stiffened with iron on fusing.

The goal of this basic workshop was to concentrate on getting participants familiar with the materials and techniques that can be used in a wearable project. So I used the congress wiki to create a Basic Electronic Fashion workshop page for the second day of the event, which would run for 2 hours and cost €6. I had no idea if people would turn up.

When I arrived at congress I met up with some of my maker type hackers friends and commandeered a small table in the Hardware Hacking Area to show off my wearable pieces and projects and a small piece of paper advertising the workshop. The wearable pieces received a lot of interest with lots of questions and comments about what it was and how it worked. The most common question was “can it be washed?”, my answer was “yes with a careful hand wash”.

The workshop went very well, about 25 took part in the introduction part and 14 stayed for the hands on part. Over the remaining days another 6 people did the hands on part of the workshop which I ran in an ad-hoc manner in the Hardware Hacking Area.

I was also interviewed in English as part of a series of German language articles in the news website Spiegel Online about the activates taking place and some of the people attending 29c3. LED-Kunst auf dem 29C3 (Google Translation).

Hamburg city and the new conference location (CCH) will take a little bit of getting use too but it’s off to a very good start. I’ve collected my photos of 29c3 and Hamburg in this photo album.

Now finally I need to write up product pages for my new SEWIO8 and SEWIO16 boards.

Thursday was the Open Hardware Summit at the Eyebeam Art + Technology Center in Manhattan, organised by the Open Source Hardware Association. It was a very intense day with thirty three talks, thirty eight demos and nine posters and a number coffee/lunch breaks giving opportunities to talk with other delegates. Highlights for me were the talk from Bre Pettis – Challenges of Open Source Consumer Products, the many talks about the use of Open Source Hardware in science and the demo of UmTRX: The open hardware for a GSM base station.

Friday, Saturday and Sunday were spent at the Maker Faire site at the New York Hall of Science in Queens. Friday was setup day and it felt exactly like being back home in Ireland as it rained most of the day.

We brought four types of projects with us to represent some of the activities we’ve undertaken at TOG.

I brought a Ten Time Scale Giant Arduino Starter Kit project, which I initially started for the Dublin Mini Maker Faire.

Jeffrey brought materials to make two improved version of the Interactive Buzzer Game which uses a Arduino for time display and hit counter and capacitive touch sensing to allow the hand-held loop to be wireless.

We also brought two wearable pieces; chebe’s blue led matrix top and a proof of concept design which uses an add-on board which I developed for use with LilyPad Arduino wearable circuits.

I also brought a small selection of my more portable LED displays including a new 32×40 RGB panel with I assembled during EMFCamp.

We planned to spend Friday assembling and Giant Arduino and Buzzer Game and finishing off some of the code. But due to it raining most of the day, a mini maker faire producers meeting and the meeting the maker mixer evening we only got a small proportion of the preparation work done.

Saturday morning was a rush to get as much done as possible before the gates opened, along with sourcing some final materials and a tarpaulin to provide protection in case it started rain again.

I was not able to finish the Giant Arduino Stater Kit due to the time constraints and not having a suitable soldering to solder wires to the copper pipe used in the headers. But the resulting board really looked like a Giant Arduino. Jeffrey had some issues with the hardware not having enough suitable components for two game and having time to soldering it all together and time to tune the software.

Otherwise the day went very well with lots comments like “thats a big Arduino” and “you came all the way from Ireland to Maker Faire”.

In the evening as we were leaving the Maker Faire we bumped into some of the members from Alpha One Labs hackerspace and we joined them for some food at a BBQ place in Brooklyn.

For Sunday Jeffrey was able to make significant progress with the hardware and software for the buzzer game so with a little bit of tunning he was able to get one the games working successfully. Unfortunately an intense thunderstorm blew in and left makers and visitor running for cover, luckily the storm only lasted about 10 minutes.

After the rain a flock of TOG Ducks made a visit to our stand.

Later in the day I got a quick chance to look around the Maker Faire myself, though it was so big I missed some of the projects from the crafters.

After the Maker Faire we were exhausted, we packed our bags and went to bed.

On Monday we got the subway to Manhattan to do a quick bit of sightseeing. It was a bit of an unplanned track by foot from Central Station to Central Park to Penn Station. Then back to the hostel to collect our bags and then to JFK airport for the airplane back to Dublin.

Some personal notes to work on for next time:

• At events like the OHS I must be more willing to start conservations. I would like to see the other participants as my peers, in theory we have lots of things in common.
• Keep the number of projects that need work at the Maker Faire to an absolute minimum, preferably no major work on site.
• Take time ot visit the other makers, schedule to have at least three makers per day at the stand.
• Try to meet up with other makers/hackers/hackerspaces outside of OHS/Maker Faire.
• Know when a project isn’t going to be ready and be willing to scale it back.
• Take more photos and video of stand and the visitors.
• Eat, drink and take breaks more often.

Some of the trips I’m planning/thinking about for later this year and next year include 29th Chaos Communication Congress in Germany, UK Maker Faire UK, Maker Faire Bay Area and OHM2013: Observe. Hack. Make. in The Netherlands.

And finally I’ve joined the Open Source Hardware Association as a General Member.

Some initial project ideas were collected on a wiki page in the days before the Hack Day. Part of a set of interrelated project’s caught the eye of one of the organisers and he suggested that the submitters get in contact with me for some input and maybe to help.

All the Aurora Orrery project’s revolved around the Aurora or in the northern hemisphere Aurora Borealis or Northern Lights. Which are caused by charged particles from the sun effected by the earths magnetic field interacting with the upper atmosphere. The result is a spectacular light show in the sky which is more visible as you get nearer the polar regions. But given a high level of of solar activity and favorable weather patterns, the Aurora can be seen from Ireland in places like Donegal and other parts of Northern Ireland.

So using the available data sources the goal was to visualise current Aurora activity which could then be used to help predict future Aurora activity which would be visible from Ireland.

Obviously I took on the sub project that involved using LEDs to represent Aurora activity. So the Thursday before we had a quick exchange of ideas using twitter and email. I pointed out some of my previous LED projects and tried to get an idea of how many LEDs might be needed to give a reasonable effect. A response in the hundreds was overly ambitious for a one day event with almost no preparation time.

So I collected up a bunch of useful through hole components, LEDs, prototype boards, wire, tools and micro controllers in shopping bags (about six). I got a hand bring them to DCU by some other members of TOG who helped build and run the network for the weekend.

On the first day; nine project ideas were present through a series of parallel lighting talks and then a lot of ad hoc discussion between participants. Groups formed around the project ideas and the hacking began.

I didn’t get started straight away as I spent some time talking through the design options and trying to decide what level of realism we could achieve. In the end with the time available and components I brought with me, I decided to build a 16 pixel RGB display with the pixels arranged in a ring. These could then illuminate the inside of a sphere or dome giving an Aurora effect forming an Aurora Lamp.

The components I used were 16 5mm RGB Common Anode LEDs, an mbed NXP LPC1768 (which I’ve used in most of my recent projects), three TLC5941 (a 16 Channel LED Driver with PWM from Texas Instruments) and some resistors and capacitors. I had used a 28 pin HTSSOP version of the TLC5941 before but for this project I used the 28 pin DIP part as it could be plugged directly into a breadboard/stripboard.

After quickly going through the TLC5941 datasheet I drew up a schematic for a driver board using gschem. I then assembled a prototype circuit on a couple of breadboards with just a couple of LEDs for testing. I used the source code from the previous TLC5941 project as a base. After couple of quick code revisions, uploading and testing I went ahead and started to solder up a stripboard version. The testing didn’t give me the exact results I was expecting but I went ahead anyway.

While I can get really good result with stripboard. I find it very very time consuming, counting holes, cutting/stripping wire, soldering, breaking strips and correcting mistakes. So fast forward many hours…

Once the driver board was fully soldered up I started working on the ring of LEDs. I used a piece of cardboard from pizza box to form the base and used a cable reel from a electrical cable to form a stand.

Because I didn’t have a compass or protractor I used paper plates and pieces of folded paper to layout the correct angles and positions on the cardboard. Carefully using a craft knife I cut out the disk and cut small slots for the LEDs. The Common Anode lead of the LED was bent and then inserted through the small slot, then Anode leads where then soldered together with a ring of tinned wire.

Using wire form cutup pieces of CAT5 cable I began soldering a wire to each LED Cathode and feeding it through the cable reel. I matched up the LED colours with the colour of the wires (red to orange/orange white, green to green/green white, blue to blue/blue white). I then connected these wires in to the connectors without sorting out the order but just matching up the colours.

Then came the smoke test, good news no smoke. But I still wasn’t getting the result I was expecting. I should have been seeing the primary colors but the were mixed up a bit. The first TLC5941 was very hot maybe I had damaged it or connected it up incorrectly.

So I began checking that the schematic was correct and that I had connected everything up correctly. I tried using another TCL5941, no luck. Even though I had pulled an all nighter, everything seemed correct to me.

Then I started looking at the code in much more detail and compared it with code from another similar project. Fairly quickly I notice that the code I copied had used a different SPI port then the one I connected up in the schematic. A quick code change, recompile and reload and I got the solid primary colours I was expecting.

What added to the confusion was that I did see some changes in colours. But I get the feeling that this was cased by breadboard/stripboard traces acting like small antennas, interesting.

With about an hour left we began working on a dome to form the lamp. Connor was at home overnight and was able to find an old paper lamp shade in the shape of a sphere. We cut a hole out of the bottom of the shade so that the LED disk could fit inside. Using sheets of paper, wire and sticky tape we formed two tubes which help to keep the paper sphere upright. It would also help to direct the LED light to form a pleasing halo effect.

The final task was to present my project for judging, I didn’t have time time or energy to do up slides so I just got the lights turned down a quickly described the project. Even with a poor presentation I won the Hardware Award (you can see the presentation photo here).

So the end result of a weekends work (and some follow up work in TOG) can be seen in the follow slide show.

Laser Tag is a multi player shooting game like paint ball. But instead of paint, pulses of infrared light are used to hit opponents. Commercial Laser Tag game systems are commonly known as Quasar in the UK/Ireland or Q-Zar worldwide. These systems can be found installed in bowling alleys or amusement arcades. DIY Laser Tag game systems also exist like the popular MilesTag system.

So when I heard that a hackable event badge called the r0ket was being developed for Chaos Camp 2011 by CCC Munich. I felt it would be a interesting platform to try and develop a DIY Laser Tag system with.

During camp I documented my progress on the camps wiki. Over the days and nights at camp I produced three prototype m0duls using strip board and a selection of components I brought with me. I wrote basic software to allow the r0ket and m0dul to be able to shot and be hit. The hardware selection was inspired by the MilesTag system and software should be compatible with the MilesTag II Data Protocol.

Directly after camp I didn’t make time to work on this project. But when I heard that a new batch of r0ket’s would be available at 28th Chaos Communication Congress (28c3) I started working on the project again.

For the next step in the this project I did some quick research on the capabilities of the micro controller on the r0ket. The MCU is a LPC1343 32-bit ARM Cortex-M3 with 32k of Flash and 8k of RAM from NXP. I was particularly interested in it’s pulse width modulation (PWM) support which could be used to modulate the IR pulses. In the camp version of the m0dule I used delay loops which was far from optimal. PWM on the LPC13xx chips is implemented using timers and match registers which can directly toggle the GPIO pins when the timer’s registers match programmable values.

Unfortunately none of the select pins on the m0dulebus of the r0ket connected to these PWM pins on the LPC1343, so I needed to come up with an alternative solution. My proposed solution was to use an external oscillator to generate the 56kHz carrier signal and have the r0ket just turn it on and off as needed to fire the pulses. After a bit of research I settled on using a 555 timer IC in astable mode.

Logically the improved Laser Tag m0dul v0.8 Prototype consists of three separate boards. A control board connecting directly to the m0dulbus, an IR transmitter board housed inside the gun barrel, and one or more IR detector boards placed on the players body.

On the control board I used a TS555CN, a low power 555 CMOS timer from ST Microelectronics which would work with the 3.3 volts provided by the r0ket. A quad NAND gate is used to turn on and off the 555 and to modulate the signal from the active low outputs of the m0dulebus select pins. Sound output on the control board was to be provided by an ISD1740 voice recorder and playback chip from Nuvoton. The ISD1700 range of chips are inflexible for this project and hard to program, so I will replace it in a future revision (I will document my findings on the ISD1700 for the record in a future blog post). A speaker, trigger button and connection headers are also provided on the control board.

The transmitter board has an IR LED, a TSAL6100 High Power IR Emitter from Vishay Semiconductors. To greatly improve the range of the IR LED over 500 milliamperes is past through it and controlled a TN0106 MOSFET from Supertex Inc. Two additional LED mounting spaces are provided these can be used to provide a muzzle flash effect and are also switched by the MOSFET. A separate set of four AA batteries in series are used to power the IR transmitter board.

The detector board has space for two TSOP34856 IR Receiver Module’s from Vishay Semiconductors to detect shot pulses. The TSOP34856 receiver has a pin diode and pre amplifier which can filter and demodulate 56kHz modulated signals. With an active low output, multiple TSOP348 receivers can be connected one MCU pin. A MCU controlled LED is also provided to allow a visual indication of a successful hit.

The physical arrangement of a tagger has the IR LED placed at the focal-point of a lens, Leif Bennett has a good page on choosing a Lens. I went with an acrylic plano-convex lens with a 40mm diameter and a 180mm focal length, a OPL8A from GreenWeld. This mounts nicely on a regular 40mm diameter white plastic waste pipe available here in Ireland. By cutting suitable slots in the waste pipe and shaping the PCB I was able to slot them together forming a rigid connection and at the same time mount the LED at the focal-point of the lens. I left extra board in the PCB layout which could be used to form a basic handle after shaping.

In order to have boards available for congress I had to get the boards fabricated in mid December before I had fully tested the design. In the mean time I etched a couple of boards myself, these boards proved the schematic and layout worked. But I did make some minor changes to make self etched boards easier to work with particularly because of the lack of through plated holes/vias.

At the last minute while testing the prototype with an oscilloscope and frequency counter I noticed that the frequency of the 555 didn’t match with what I had calculated, about 42kHz instead of 56kHz. I had to search through my selection of resistors to find a suitable combinations of values which would generate the correct frequency.

During congress I assembled a second prototype and updated the firmware to work with the hardware changes. In tests inside the Berliner Congress Center (BCC) we found that the hits could be registered over about 30 meters, in a test we tried outside the hits worked over 100 meters. On reflection these long range tests worked too well and probably show that the optical arrangement needs to be tuned so the beam spot is much smaller.

A pdf of the schematic can be downloaded here:
Laser Tag r0ket m0dul v0.8 Schematic

The TODO list includes documenting the board assembly; and releasing the schematic, layout and source code.

The workshop are suitable for beginners and you can sign up by clicking on the links below

Basic Soldering Workshop

This hands on workshop will cover the basic techniques of soldering, how to solder electronic components and making up simple electronic circuits.

Cost: €15 General public, €12 Students/Unwaged, €10 Hackerspace members.

All tools and materials are provided. No electronics skills are required. The workshop is suitable for mature teens and up.

TOG : Dublin : Sunday 21st : 12:00 – 14:30
Nexus : Cork : Friday 26th : 18:00 – 20:30
Milk Labs : Limerick : TBC
091 Labs : Galway : TBC

Mini Mood Light Soldering Workshop

During this workshop Robert Fitzsimons will guide participants in assembling his open hardware Mini Mood Light kit. The Mini Mood Light uses a MSP430 micro controller and four buttons to to control the colour of two RGB LED. The default code allows the user to use the buttons to change the colour to represent their mood. The workshop will including an overview of the circuit and code operation.

Cost: €20 General public, €17 Students/Unwaged, €15 Hackerspace members.
Optional extras: €2 9 Volt battery, €6 MSP430 LaunchPad.

All tools and materials are provided. Only very basic electronics skills are required. The workshop is suitable for mature teens and up.

TOG : Dublin : Sunday 21st : 15:00 – 17:30
Milk Labs : Limerick : TBC
091 Labs : Galway : TBC

At the camp I’m planning to spend a lot of time in the Hx2 Hardware Hacking Area. I had originally signed up to give a hands on workshop on Introduction to PCB Etching, but I can’t bring the chemicals on the plane. So I’ve come up with another project for a workshop.

The project for the workshop will be to create a custom m0dul for the r0ket badge which can be used to form a Laser Tag system. This m0dul will be designed from scratch including hardware and software starting this weekend and during the camp, though inspiration for parts has come from DIY discussions on the Laser Tag Forums. Materials cost will be approximately €50.

In addition I’ll be bringing ten soldering sets for use in the Hardware Hacking Area, Mini Mood Light v1 Kit, I Can Solder Badge v1 Kit and other bits & bobs.

Just hopping all the parts arrive in time.

Members from Irelands hackerspaces and makerspaces have been invited to build a temporary hackerspace in the park over the weekend. Giving visitors the opportunity to experience the possibilities of hacker and maker culture in Ireland. We’ll be showing off existing projects, teaching new skills through activities and workshops, and working on new projects with visitors and the resources we’re bringing over the weekend.

In MindField Hackerspace I’ll be helping to run a hardware hacking area teaching people to solder repair and re-propose, and giving a free Introduction to Arduino Workshop. I’ll also be talking part in the Hack the Planet! panel discussion on hackerspaces.

In the hardware hacking area I’ll be selling some of my kits including the Mini Mood Light v1, Dual LED Matrix Display and other LED based displays. All along with Arduino Uno’s, TI LanuchPad’s, electroluminescent wire and hundreds of LEDs.

One very special item I’ll have for sale is a basic I Can Solder kit which is in the form of a badge. The I Can Solder badge was inspired by the Electronic Merit Badge from Make:. Which I had the pleasure of using to help teach hundreds of kids and adults to solder during the Maker Faire UK in March in New Castle, England.

The circuit forms an interface between a micro controller and a 8 by 8 Dual Colour Common Anode LED Module. This type of module has two LEDs per pixel, each row has 8 pixels, with 8 rows. The anodes of each LED in a row are connected, with 16 columns formed by connecting together the cathode of an LED from each row.

A high side switch is needed to turn on/off a row and must be able to source approximately 240 milliamperes (16 multiplied by 15 milliamperes). A low side switch is needed to turn on/off a column, but only one LED is on per column so it only needs to sink 15 milliamperes.

For the high side switching I used a TD62783APG 8 Channel High-Voltage Source Driver from Toshiba Semiconductor. It’s very important that only one output from the TD62783 is on at any one time so I used a 74HC238 3-to-8 Decoder from NXP to control the row selection. For the low side switching we used two 74HC595 8-bit Shift Registers from NXP.

Only one row of LEDs is on at a time, the display uses persistence of vision to give the illusion that all the LEDs are active at one time.

The basic operation for displaying a single frame is. The data for a row is shifted into shift registers one bit at a time, the shift register output is turned off (OE), the row is selected on the decoder, the shift register data is loaded into the output registers (LE) and then the shift register output is turned on. These steps are repeated for each additional row of data. All the steps are repeated indefinitely until the next frame of data is to be displayed.

The circuit was designed around the Arduino micro controller but should work with other micro controllers. The connections are shown in the image. The left hand side of the display is the row select pins the central pins are for power and ground, with the columns connected to serial peripheral interface (SPI) pins on the Arduino on the right.

Dual 8×8 Matrix v0.1 Schematic

I’ll do a follow-up blog post with the source code and a Java program I’ve written to create animations.

Our general idea was to create a little badge with LEDs in the shape of a shamrock. We were hoping for something small, light and bright with lots of LEDs. I said that I would do some more research to see if it would work and if it did to come up with a suitable circuit design.

I knew the general idea was to use a step-up (boost converter) to increase the voltage level so to that I could drive a string of LEDs. I then began to search manufactures sites for suitable components and relevant information.

After searching all the main contenders I found a very interesting range of chips in a small five pin surface mount package from ON Semiconductor. The most interesting options were the CAT4137 LED Driver, Boost, 5 LED and CAT4238 LED Driver, Boost, 10 LED. Another option from Linear Technology was the LT1932 – Constant-Current DC/DC LED Driver in ThinSOT. As I wasn’t sure what would work I ordered a couple of each component and the suggested supporting components. Along with lots of green surface mount LEDs.

I then designed and etched a simple proof of concept board. After soldering it up and connecting up a CR2032 coin cell battery it worked but I was disappointed with the brightness of the LEDs.

I then put the project on hold. Roll on a couple more weeks and I looked at this project again.

Investigating the proof of concept board I realised I had used a wrong resistor value and was trying to supply 30 milliamperes instead of 10 milliamperes into the string of LEDS. Changing this didn’t really help increase the brightness. But it did point me in the direction that I was just trying to draw too much current from the battery.

I found the following blog post on using cr2032 coin cells from Marcus from Interactive Matter (who I meet at 27c3) very informative. Connecting up the circuit to two AAA batteries solved the brightness problem.

I have now reworked the board into a near final layout. And as a token gesture to the 14th of February (Valentines Day) I’ve created a design in the shape of a heart.

Tomorrow I’ll finish the prototype of the shamrock badge and post a picture. If I created a kit would you be interested in buying it?

Update: Here is the photo of the prototype for the shamrock badge. When we looked at it after I assembled the badge it was hard to make out the leafs also I might change the resistor value to increase the brightness.

I’ll be helping Jeffrey with his free Arduino 101 – Learn to Blink on Tuesday, the Soldering Workshop on Saturday and I’ll be giving a new LED Dot Matrix Display Workshop on Sunday (I hope to do a write up soon).

During the week I have a number of Arduino Uno‘s boards available for €30.

Also over the weekend I’ll take part in the Synchronous Hackathon and I hope to have time to help with TOG’s Hackerspace 555 Timer Challenge entry for the 555 Contest.