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{{Infobox-hw-en
{{Infobox-hw-en
|Name = LED-23
|Name = LED-23
|Jahr = 2007
|Jahr = 2006
|Pixel = 19
|Pixel = 19
|Farben = red/yellow
|Farben = red/yellow
|Leuchtmittel = low current LED
|Leuchtmittel = low-current LEDs
|Leistung =  
|Leistung =  
|Kontakt = [[User:ArneRossius|ArneRossius]]
|Kontakt = [[User:ArneRossius|ArneRossius]]
|Sonstiges = [http://elektronik-kompendium.de/public/arnerossius/schaltungen/avr/23.htm LED-23 im Elektronik Kompendium]
|Sonstiges =  
}}
}}
{{FlagDe|target=LED-23}}
{{FlagDe|target=LED-23}}
''[[Projects|back to overview]]''
''[[Projects|back to overview]]''
[[Image:LED-23-03.jpg|thumb|150px|[[Niob]]'s LED-23]]
[[Image:LED-23-03.jpg|thumb|150px|[[Niob]]'s LED-23]]
=== Description ===
=== Introduction ===


This little project was developed spontaneously, when somebody invited me to his 23th birthday only two days before the party. I needed a nice present and due to the special meaning of the number 23, I decided to built up this circuit which is connected to that number and gets a double sense.
This little project was developed spontaneously, when somebody invited me to his 23th birthday party only two days in advance. I needed a nice present and due to the special meaning of the number 23, I decided to build this circuit.


This circuit consists of a ATTiny11-Microcontroller which shows different effects onto the 19 LEDs (unfortunately not 23 LEDs ;-) ) composed as the number 23 and is operated by a 9V battery. Hence, the LED-23 keeps small and can be alingned almost everywhere.
This circuit consists of an ATTiny11 microcontroller which shows different effects with 19 LEDs (unfortunately not 23 LEDs ;-)) composed as the number 23 and is operated by a 9V battery. Hence, the circuit could be kept small and can be put almost everywhere.


=== Kits ===
=== Kits ===


Since [[24C3English|24C3]] LED-23 kits are available at the price of 10 Euros. It includes the board, all parts, a 9V battery and a detailed instruction. If you are interested to get one, please get in contact with [[User:ArneRossius|Arne]]. The kit is proper for beginners and contains no SMD parts.
Since [[24C3English|24C3]] LED-23 kits are available at the price of 10 Euros. They include the circuit board, all parts, a 9V battery and detailed instructions in english. If you are interested to get one, please get in touch with [[User:ArneRossius|Arne]]. The kit is appropriate for beginners and contains no SMD parts.


At the moment, 6 kits are available.  
At the moment, 2 kits are available, one of them with all yellow LEDs and the other red/yellow mixed (as shown below).


=== Built up ===
=== Buildup ===


<span style="color:#1C1C1C;">Die Schaltung lässt sich trotz der etwas problematischen Anordnung der LEDs auf einer Lochrasterplatine aufbauen, wenn man einige LEDs waagerecht und andere senkrecht durch die Löcher steckt. Aufgrund des sehr geringen Platzes konnte ich nur einen achtpoligen AVR einsetzen und habe mich für den Tiny11 entschieden, der zwar nur wenige Features bietet, für diese Schaltung aber locker ausreicht. Um die vielen LEDs alle einzeln ansteuern zu können, kommt eine spezielle Multiplexing-Technik mit dem Namen Charlieplexing zum Einsatz, die die Möglichkeit ausnutzt, dass die Portpins des AVR neben "null" und "eins" auch noch hochohming geschaltet werden können (Eingang ohne Pullup). Auf diese Weise schafft man mit den fünf vollwertigen Portpins (der Reset-Pin kann nur als Eingang verwendet werden) 20 LEDs anzusteuern, also gerade genug für die 19 LEDs dieser Schaltung. Durch das Multiplexing sind die LEDs allerdings etwas dunkel, zumal die Portpins zum Teil auch recht viel Strom liefern müssen - es fließt also ein recht geringer Strom durch die LEDs. Wer genug Zeit hat, welche zu besorgen, sollte statt der von mir verwendeten Standard-LEDs auf jeden Fall Low-Current- bzw. High-Efficiency-LEDs einsetzen, die auch mit wenig Strom schon hell leuchten. Eine weitere Helligkeitssteigerung kann man durch Weglassen der Dioden erreichen (einfach durchverbinden) - ich bin mir allerdings nicht ganz sicher, ob das tatsächlich funktioniert, deshalb habe ich sie vorsichtshalber mit eingebaut.</span>
Despite the weird LED arrangement, the circuit can be built on a perfboard if you insert some LEDs vertically and others horizontally. Because there wasn't much room left with the LEDs all over the board, I had no choice but to use a small 8-pin AVR. I decided to use an ATTiny11 which has very little features but is sufficient for this circuit and very cheap. To control all the LEDs with just 5 output pins, I used a special multiplexing technique called "Charlieplexing" that uses the possibility to tri-state the outputs (switch to input without pullup). With this method, it is possible to control 20 LEDs, just enough for the 19 LEDs in this circuit. Unfortunately, the LEDs are a little darker than usual because of the multiplexing as the port-pins can't supply a lot of current. If you have enough time to buy some, get some low-current or high-efficiency LEDs, they'll light up bright with just a small current flowing through them. The LEDs become even brighter if you omit the diodes (just connect the anode with the cathode). At the time I built it, I wasn't sure that was going to work so I added them as a precaution, the kits don't have them though.  


<span style="color:#1C1C1C;">Verkabelt habe ich die Platine diesmal aus Platz- und optischen Gründen nicht mit normaler 0,14 mm2-Litze, sondern mit besonders dünner 0,09 mm2-Litze. Die passt auch mit Isolierung wunderbar durch die Löcher der Platine durch, so dass an besonders engen Stellen auch mal ein Stück des Kabels unter der Platine verlegt werden kann. Optimal wäre natürlich eine professionelle, geätzte Platine gewesen, aber dafür hatte ich naürlich keine Zeit mehr :-(.</span>
I wired the perfboard with a very thin 0.09 mm² wire (about 30 AWG) for lack of space and because it looked better. It fits though the holes in the perfboard even with insulation so it was possible to continue passing the wire on the solder side in very tight spaces. Of course, a professionally made PCB would have been optimal, but there wasn't time.


<span style="color:#1C1C1C;">Die Software ermöglicht es, dass Animationen mehrfach wiederholt werden, bevor die nächste abgespielt wird. Auf diese Weise muss die Animation nur einmal im Speicher stehen, so dass man auch im einen Kilobyte des Tiny11 ein ausreichend langes Animationsprogramm zusammenbekommt. Die Animationen habe ich der Einfachheit halber in einzelnen Assemblerdateien abgelegt, die dann per Include-Direktive eingebunden werden. Da immer eine gerade Anzahl Bytes in jeder Zeile stehen muss, gibt es zum "Auffüllen" noch einen No-Operation-Befehl, der beim Anzeigen der Animationen einfach ignoriert wird. Letztendlich muss am Ende der Animationen noch ein besonderer Befehl stehen, damit das Programm wieder an den Anfang der ersten Animation springt. In der Version die hier heruntergeladen werden kann sind allerdings alle Original-Animationen enthalten und fertig eingebunden, Sie können es also auch ohne Änderungen direkt benutzen.</span>
The software allows for animations to repeat a number of times before continuing with the next one so every animation just needs to be stored once. This means the one kilobyte flash memory of the ATTiny11 is enough for a decent-length animation programme. For simplicity, I used seperate assembler files for each animation which are included into the main programme source. As every line must consist of an even number of bytes, there is a No-Operation-Command which is ignored when displaying the animation that can be used to fill lines with an odd number of bytes. Lastly there is a command that marks the end of the animation sequence so the programm knows when to jump back to the beginning of the first animation. In the version available for download below, all original animations are already included so you can use it without having to change it.


* [[:Image:Led-23.png|circuit]]
* [[:Image:Led-23.png|circuit]]
* [[:Image:23leds.png|LED composition]]
* [[:Image:23leds.png|LED composition]]
* [[:Image:Led-23.zip|assembler code and hexfile]]
* [[:Image:Led-23.zip|assembler code and hexfile]]
* [[:Image:23creator.zip|software to create movies (VB6 source code and Windows-EXE-file, might include some bugs!)]]
* [[:Image:23creator.zip|software for creating animations (VB6 source code and Windows-EXE-file, might include some bugs!)]]


=== Photos ===
=== Photos ===
{| border=0
{| border=0
| [[Image:23_oben.jpg|left|200px]]
| [[Image:23_oben.jpg|left|200px]]
| This is the top of the board with the 19 LEDs and the other parts arranged closely. In consequence of having not enough LEDs of the same colour, I used the red and yellow ones ;-).
| This is the top of the board with the 19 LEDs and the other parts cramped between them. In consequence of not having enough LEDs of the same colour, the two digits are different colours ;-).
|}
|}


{| border=0
{| border=0
| [[Image:23_unten.jpg|left|200px]]
| [[Image:23_unten.jpg|left|200px]]
| If one has a closer look at the soldering side, the usual SMD capacitor can be seen between the soldering points of the voltage controller (the other one is covered by the red wire).
| Closely looking at the solder side, one of the two SMD capacitors can be seen between the soldering points of the voltage regulator (the other one is covered by the red wire).
|}
|}


{| border=0
{| border=0
| [[Image:23_an.jpg|left|200px]]
| [[Image:23_an.jpg|left|200px]]
| The 23 in use (the LEDs of the upper line of the three are not darker than the others but flashed up during the exposure of the picture).
| The 23 in use (the LEDs of the three's upper line are not darker than the others but flashed up during exposure of the picture).
|}
 
{| border=0
| [[Image:23-bausatz.jpg|left|200px]]
| The kit version with a professionally made PCB.
|}
|}

Revision as of 14:28, 23 June 2008

LED-23
Year 2006
Number of pixels 19
Grayscales / Colors red/yellow
Illuminant low-current LEDs
Power Input
Contact person ArneRossius
Project website
Miscellaneous
Zur deutschsprachigen Version dieser Seite

back to overview

Niob's LED-23

Introduction

This little project was developed spontaneously, when somebody invited me to his 23th birthday party only two days in advance. I needed a nice present and due to the special meaning of the number 23, I decided to build this circuit.

This circuit consists of an ATTiny11 microcontroller which shows different effects with 19 LEDs (unfortunately not 23 LEDs ;-)) composed as the number 23 and is operated by a 9V battery. Hence, the circuit could be kept small and can be put almost everywhere.

Kits

Since 24C3 LED-23 kits are available at the price of 10 Euros. They include the circuit board, all parts, a 9V battery and detailed instructions in english. If you are interested to get one, please get in touch with Arne. The kit is appropriate for beginners and contains no SMD parts.

At the moment, 2 kits are available, one of them with all yellow LEDs and the other red/yellow mixed (as shown below).

Buildup

Despite the weird LED arrangement, the circuit can be built on a perfboard if you insert some LEDs vertically and others horizontally. Because there wasn't much room left with the LEDs all over the board, I had no choice but to use a small 8-pin AVR. I decided to use an ATTiny11 which has very little features but is sufficient for this circuit and very cheap. To control all the LEDs with just 5 output pins, I used a special multiplexing technique called "Charlieplexing" that uses the possibility to tri-state the outputs (switch to input without pullup). With this method, it is possible to control 20 LEDs, just enough for the 19 LEDs in this circuit. Unfortunately, the LEDs are a little darker than usual because of the multiplexing as the port-pins can't supply a lot of current. If you have enough time to buy some, get some low-current or high-efficiency LEDs, they'll light up bright with just a small current flowing through them. The LEDs become even brighter if you omit the diodes (just connect the anode with the cathode). At the time I built it, I wasn't sure that was going to work so I added them as a precaution, the kits don't have them though.

I wired the perfboard with a very thin 0.09 mm² wire (about 30 AWG) for lack of space and because it looked better. It fits though the holes in the perfboard even with insulation so it was possible to continue passing the wire on the solder side in very tight spaces. Of course, a professionally made PCB would have been optimal, but there wasn't time.

The software allows for animations to repeat a number of times before continuing with the next one so every animation just needs to be stored once. This means the one kilobyte flash memory of the ATTiny11 is enough for a decent-length animation programme. For simplicity, I used seperate assembler files for each animation which are included into the main programme source. As every line must consist of an even number of bytes, there is a No-Operation-Command which is ignored when displaying the animation that can be used to fill lines with an odd number of bytes. Lastly there is a command that marks the end of the animation sequence so the programm knows when to jump back to the beginning of the first animation. In the version available for download below, all original animations are already included so you can use it without having to change it.

Photos

23 oben.jpg
This is the top of the board with the 19 LEDs and the other parts cramped between them. In consequence of not having enough LEDs of the same colour, the two digits are different colours ;-).
23 unten.jpg
Closely looking at the solder side, one of the two SMD capacitors can be seen between the soldering points of the voltage regulator (the other one is covered by the red wire).
23 an.jpg
The 23 in use (the LEDs of the three's upper line are not darker than the others but flashed up during exposure of the picture).
23-bausatz.jpg
The kit version with a professionally made PCB.