LEDancer

From doityourselfchristmas.com
Revision as of 23:59, 18 March 2012 by Jklingert (talk | contribs)
Jump to navigation Jump to search

General

The LEDancer (Le Dancer) is an inexpensive controller for up to 56 LEDs with a DMX512 input interface. The LEDs are connected together in a Charlie-Plexed common-cathode configuration. The design needs to use 2N3906 booster transistors for the LED cathodes to ensure that the low-level drive of the PIC is not exceeded, a configuration sometimes called chipi-plexing. The DMX address of the controller can be changed by shunting one of the PIC pins to ground and then sending a specially formatted DMX packet with the desires address.

PCB Schematic

This is a generic LEDancer schematic, useful as the basis of a PCB design. Some of the necessary details (such as a DC regulator) have been omitted from the schematic, but should be included in most PCB designs.

PCB Design

At the moment there isn't a released PCB design. The design consists of a controller board (with a PIC16F1826 and a ST485 RS485 receiver, a jumper for enabling the DMX Address Program Mode, eight resistors and 8 2N3904 transistors, and some connectors.

Here is a proposed sample PCB design (note that it still needs caps next to the Voltage Regulator):

Video

Click here for a demo video of the LEDancer

Connector Pinout

Jumper Identification

BOM - Bill Of Materials

Mouser

Mouser PNDescriptionQty
538-22-03-2021Headers & Wire Housings VERT PCB HDR 2P TIN PLATING2
538-22-03-2061Headers & Wire Housings VERT PCB HDR 6P TIN PLATING1
538-22-03-2031Headers & Wire Housings VERT PCB HDR 3P TIN PLATING3
80-C322C104K5RMultilayer Ceramic Capacitors (MLCC) - Leaded 50volts 0.1uF 10% X7R1
80-C322C334M5U5CAMultilayer Ceramic Capacitors (MLCC) - Leaded 50volts 0.33uF 20% Z5U1
299-82-RCCarbon Film Resistors - Through Hole 82ohms 5%8
512-2N3904TATransistors Bipolar (BJT) NPN Transistor General Purpose8
511-ST485BNBuffers & Line Drivers Hi-Spd Lo Pwr Trans1
579-PIC16F1826-I/PMicrocontrollers (MCU) 3.5KB Flash 256 byte 32 MHz Int. Osc1
571-1-390261-2IC & Component Sockets 8P ECONOMY TIN1
571-1-390261-5IC & Component Sockets 18P ECONOMY TIN1
604-WP7104GTStandard LED - Through Hole GREEN TRANSPARENT1
299-330-RCCarbon Film Resistors - Through Hole 330ohms 5%1



LEDs

In addition, you will need up to 56 White Piranha Style Super flux LEDs. Other colors could be used, but you may need to adjust the resistor values on the controller board.
=BOM==


LED Segment PCBs

LED Connections

THIS SECTION IS OUT OF DATE.

The LEDs can either be hand-wired on some sort of substrate (perhaps some plexiglass or linoleum), or a PCB can be designed to hold the LEDs. In all of the following diagrams LED1 is the LED controlled by the lowest DMX address, LED2 is next, and so forth. LED56 is the LED controlled by the highest (56'th) DMX address.

Schematic

Wirelist

Output1,LED1-C,LED2-C,LED3-C LED4-C,LED5-C,LED6-C,LED7-C,LED14-A,LED20-A,LED26-A,LED32-A,LED38-A,LED44-A,LED50-A

Output2,LED1-A,LED8-C,LED9-C,LED10-C,LED11-C,LED12-C,LED13-C,LED14-C,LED21-A,LED27-A,LED33-A,LED39-A,LED45-A,LED51-A

Output3,LED2-A,LED8-A,LED15-C,LED16-C,LED17-C,LED18-C,LED19-C,LED20-C,LED28-C,LED8-A,LED34-A,LED40-A,LED46-A,LED52-A

Output4,LED3-A,LED9-A,LED15-A,LED22-C,LED23-C,LED24-C,LED25-C,LED26-C,LED27-C,LED28-C,LED35-A,LED41-A,LED47-A,LED53-A

Output5,LED4-A,LED10-A,LED16-A,LED22-A,LED29-C,LED30-C,LED31-C,LED32-C,LED33-C,LED34-C,LED35-C,LED42-A,LED48-A,LED54-A

Output6,LED5-A,LED11-A,LED17-A,LED23-A,LED29-A,LED36-C,LED37-C,LED38-C,LED39-C,LED40-C,LED41-C,LED42-C,LED49-A,LED55-A

Output7,LED6-A,LED12-A,LED18-A,LED24-A,LED30-A,LED36-A,LED43-C,LED44-C,LED45-C,LED46-C,LED47-C,LED48-C,LED49-C,LED56-A

Output8,LED7-A,LED13-A,LED19-A,LED25-A,LED31-A,LED37-A,LED43-A,LED50-C,LED51-C,LED52-C,LED53-C,LED54-C,LED55-C,LED56-C

Stackable LED Board Design

Here is the schematic for a practical stackable board design. By connecting eight of these boards together (output to input, pin-1 to pin-1, etc) the previous schematic/wirelist can be readily built.

Assembly Instructions

PIC Program

Here is the first version of the firmware. It uses an LED arrangement that is slightly different from the one documented above, so it won't be particularly useful. It is, however, the latest version that has been tested on hardware, so it is included here for reference.

File:LEDancer-20110521.asm

Here is a second version of the firmware, modified to use the actual LED arrangement described earlier in this document. This is untested, however, because the author hasn't built the LED hardware yet that corresponds to the description above.

File:LEDancer-20110522.asm

Here is a third version. The only changes from the second version are comments, particularly the hardware mapping list near the start of the file.

File:LEDancer-20110527.asm

Here is the fourth version. It has changes to accommodate the current LED board revision, which is a common anode design rather than the original common-cathode design. It also has related changes to remove some ghosting issues.

File:LEDancer-20111101.asm

Programming the DMX Address

To program the DMX address, first format (using Vixen) a DMX packet with the MSB of the address in the first byte of the packet and the LSB in the second byte. Then, install the jumper J5 (in the PCB layout above), and set up Vixen to send out the DMX packet with the new address. When the controller has accepted the new address and stored in the EEPROM, the first seven LEDs will come on and stay on solid. In order to resume normal operation you need to remove the jumper J5 and cycle power on the controller off and on.

Video

Click here for a demo video of the LEDancer

Forum Threads

Initial Thread