Interfacing with Astropixels – Darren's R2D2 build

Work-in-progress documentation, expect changes and improvements over the next few weeks – DJP – 28th March 2024

One of the great parts about the Astropixels is that whilst at the simplest you can just plug them in for basic R2 lights, you can also trigger various built in effects and change colours on the fly. This is for the logics, PSIs, and HPs.

For instance, you could trigger the HP to coincide with the Leia message being played, or play the imperial march and turn R2 into full evil red mode.

The main documentation can be found with the ReelTwo library here. However, this page will break things down a little bit.

Interfacing

You can interface with the Astropixels using either serial or i2c. By default, only i2c on address 0x0A is enabled, but you can install the Astropixels Plus firmware to gain a load of other functionality, including serial and wifi (so you can use the rtouch mobile app).

Logics and PSI

The logics and PSI both run the same LogicEngine code and have the same effects available to them. You can even run the PSI light style on a logic!

All commands start with LE (for Logic Engine), followed by:

You must drop any leading 0’s.

Logic Designation:

0 – All Logics and PSI
1 – Front Logics
3 – Rear Logics
4 – Front PSI
5 – Rear PSI

Effect (Two digits):

00 – Normal
01 – Alarm – flips between color and red with mic effects
02 – Failure – cycles colors and brightness fading – roughly timed to 128 screa-3.mp3
03 – Leia – pale green
04 – March – sequence timed to Imperial March
05 – Single Color – single hue shown
06 – Flashing Color – single hue on and off
07 – Flip Flop Color – boards flip back and forth – similar to march
08 – Flip Flop Alt – other direction of flips on back board, front is same to flip flop
09 – Color Swap – switches between color specified and inverse compliment color
10 – Rainbow – rotates through colors over time
11 – Red Alert – shows color specified based on mic input
12 – Mic Bright – brightness of color specified back on mic input
13 – Mic Rainbow – color goes from default specified through color range based on mic input
14 – Lights Out – turns off displays
15 – Static Text
16 – Text Scrolling Left
17 – Text Scrolling Right
18 – Text Scrolling Up
19 – Roaming Pixel (pixel roams from top left to bottom right – for testing)
20 – Horizontal Scanline
21 – Vertical Scanline
22 – Fire
23 – PSI Swipe between two colours
24 – Pulse
99 – Select Random Effect

Colour:

1 – Red
2 – Orange
3 – Yellow
4 – Green
5 – Cyan
6 – Blue
7 – Purple
8 – Magenta
9 – Pink
0 – Default Colour

Speed:

This is a value between 0 and 9, with 0 being the fastest

Flip Flop and Rainbow – 200ms x speed
Flash – 250ms x speed
March – 150ms x speed
Color Swap – 350ms x speed
Red Alert – sets mic sensitivity – as a fraction of speed / 10 – we recommend 3

Time (Two digits):

00 for continuous on most effects
00 for default length on Leia message
Not used for march or failure effects

Summary

So for instance you could send via i2c the command ‘LE30000’ to set all logics to a pale green for the duration of the Leia message, or ‘LE1201510’ to make the front logics run a cylon style effect. One thing to watch out for is power draw if you do some effects.

HPs

The HPs use the same commands as the FlthyMcNasty HP system, as that code was incorporated into the ReelTwo library. All these commands are prefixed with the code ‘HP’, followed by:

HP designation:

F – Front HP
R – Rear HP
T – Top HP
D – Radar Eye (Extra hardware needed, info to come)
O – Other HP (Extra hardware needed, info to come)
A – All 3 HPs
X – Front & Rear HPs
Y – Front & Top HPs
Z – Rear & Top HPs
S – Sequences (See Below)

Sequence Type:

This is either 0 for LED functions, or if you’ve added extra hardware to control servos you can use 1 to send signals to move the HPs

Sequence:

This is a two digit code

01 – Leia sequence (blue)
02 – One colour flickering
03 – Dim Pulse
04 – Cycle
05 – Colour
06 – Rainbow
07 – Short Circuit
96 – Clear Function, Disable Random LED Twitch, enable off color override, and random sequences (if enabled)
97 – Clear Function, Enable Random LED Twitch using random LED sequences, enable off color override.
98 – Clear Function, Disable Random LED Twitch, random sequences (if enabled) and disable off color override
99 – Clear Function, Enable Random LED Twitch, using random LED sequences, disable off color override

Colour (Optional):

1 – Red
2 – Yellow
3 – Green
4 – Cyan
5 – Blue
6 – Magenta
7 – Orange
8 – Purple
9 – White
0 – Random

Speed (Optional):

Speed setting integer for the Dim Pulse LED function below (0-9)

Random (Optional):

Random State Integer Values
1 = Use Default Sequences
2 = Use Random Sequences

Position (Optional – if you have extra hardware for the servos):

0 – Down
1 – Center
2 – Up
3 – Left
4 – Upper Left
5 – Lower Left
6 – Right
7 – Upper Right
8 – Lower Right