Tag: LED

More (Smart) LEDs

The Talisman V2 is using the CPU already included in the WiFi radio.  This Wifi CPU has less control wires made available than what was available from the independent CPU controller in Talisman V1.

In Talisman V1 there were 3 full color LEDs. Each full color LED used 3 wires – one wire for each of the red, green and blue LEDs. Therefore the Talisman V1 had used 9 control wires. (3 sets of 3 wires.)

Smart LEDs are being used in Talisman V2 to reduce the number of control wires. A large number of smart LED can all be controlled from one single control wire.

(This is achieved by sending the necessary color data for all the RGB LEDs over the single wire into the first LED. The first led then daisy chains the data passed along to the next LED in the sequence.)

The image above shows a V1 Talisman LED that with 3 wires on the left. On the right animated image is single smart LED. It can be seen in the right hand side photo that the little 5mm square LED has a dark chip rectangle and tiny gold wires within the white package. Each smart LED in V2 comes with a little chip inbuilt!

So, this posts shares how it is possible to reduce the number of data control wire by the use of smart LEDs from 9 to 1.  In addition it is possible to daisy chain a very large number of smart LEDs in a long sequence.

It is intended to add additional full color LEDs onto the Talisman V2, most likely in a circular ring or oval layout. This should allow the Talisman V2 to be orientated anyway an artists chooses. The Talisman V1 only had LEDs on the front edge, so V1 had to be orientated a certain way when artistically mounting.

Prototyping the smartLEDs today, uncovered a downside; they use power even when no light is being emitted! In fact their little internal chip uses so much power even when dark that they would over time significantly reduce the battery life.   For this reason it is necessary for the Talisman V2 to switch power off for the LEDs unless they are going to be shining.

It so happens that there is already a spare switched power available on the Talisman V2. The Talisman V1 used to have a Bluetooth controller that had it’s power turned on and off. This bluetooth is no longer required, so the second switched power is now used for powering on and off all the smart LEDs on V2.


Boot Successful

The various tools for developing the firmware were installed on the mac, and a very simple basic program was coded to achieve the simplest test of being able to upload source code onto the device.


The prototype was successfully programmed to simply flash through the colors of the left hand side LED.

The flashing LED shows that the development tool, the compiler, and the programming dongle are working.

An error was found and fixed with two fine copper ‘bodge’ wires. The analog voltage supply and ground was left off. A future revision of the PCB would include these connections and remove the need for the manual addition of the two small fince copper bodge wires.