Help sensor expansion board

I I stacked the sensor board on top of the pixel blaze 3 as described on the website. Doesn’t seem to be working. does the sensor expansion board need separate power going to the 3 volt pin or is it powered off the pixel Blaze 3? Also several the patterns have an impossible figure of -1 at the beginning of the code well this figure change when I’m looking at the code or is it just not used when a sensor board is detected.
Thank you

it’s powered off the PB.

What patterns are you talking about? Different people have coded many things. They don’t all work the same.

I found it easy to put the board on incorrectly and it doesn’t work. I also damaged mine to the point where it wouldn’t work even after mounting it correctly. I don’t know if I soldered/desoldered to many times or what happened. In any case I had to buy a new sensor board and it fixed the problem. I double checked my installation before I powered it up.

Hi @Twilight ,
The status area (top right of the page) will update when a sensor board is detected.


Screen Shot 2021-09-13 at 8.36.42 AM


Screen Shot 2021-09-13 at 8.36.53 AM

If that is showing up, you can inspect the data it’s sending (any exported variables) in the Vars Watch within the editor e.g. with a pattern like this:

export var frequencyData
export var energyAverage
export var maxFrequencyMagnitude
export var maxFrequency
export var accelerometer
export var light
export var analogInputs

export function render(index) {

Enabling Vars Watch you should see these values updating based on what it senses:

If it’s not detecting your sensor board, can you post photos of the mounting and soldering? We might be able to help troubleshoot remotely.

1 Like

I think I wrote the code you’re talking about in the default patterns. Ben taught me this trick for detecting whether a sensor board is connected. I commonly use it to consume sensor board data if it’s present, or to generate synthetic sensor data if one is not connected.

// Values that come from the Sensor Board
export var light = -1 // If this remains at the impossible value of -1, a sensor board is not connected.
function SB() { return light != -1 }
export var frequencyData = array(32)
export var energyAverage, maxFrequency, maxFrequencyMagnitude

This is from a recent pattern I wrote. If a sensor board is connected, Pixelblaze will be setting values for light (light is a special variable name, where if you put export var in front of it AND a sensor board is connected, the light readings start magically being populated into the variable). Even if the sensor board is in pitch darkness, light will be set to 0 instead of -1, so you know a sensor board is present. For a list of all special variables names that work this way, just see the docs on the Pixelblaze code editor page.

This technique is also shown a different way (using an impossible value in the frequencyData array) on the sensor board page.

Thank you everyone it’s obviously my solder job then! Going back and checking my connections

1 Like

That’s correct, most values are tiny numbers.

awesome thanks for the clarification yesterday I was bouncing back and forth between it is connected and wait maybe it’s not connected. Lol