Lego boost models, how they worked

[Eilderman]

Hello, my son (six years) received an unopened Lego Boost set for his last birthday. We were disappointed to find the Android app had stopped working but we've had fun anyway with some simple programming, making the robot move around. He has just completed his second model, the guitar4000, and he's going to want to play it. Does anyone know what the functionality originally was through the Boost app? It's there by any chance a repository of scripts that make the base models work the way they were supposed to? I'd appreciate any help. He loves this set but it's some work to try to stand in for the dead app, especially since I'm a fairly novice programmer myself.

[dlech]

I was curious, so I just tried the BOOST app on my phone and it still seems to be working. What part doesn't work for you?

[Eilderman]

Really? The only thing that works for me is installation. I've tried it on every Android device in our house and found information somewhere online (almost a year ago now) that Lego had disabled it. I had installed the Boost app and verified that it worked before recommending that my parents buy the set for my son then the app wouldn't start when we finally got the set. I uninstalled and tried to reinstall but the Play store wouldn't let me: "this app is made for an older version of Android". I found an apk online, somewhere that didn't seem too sketchy, and tried that but the app crashes on startup. I see a loading screen and nothing further.

What device does it work on for you? I'll buy it from you!

[Eilderman]

I'm kidding I guess but just barely. The app looks like it just have been a blast for kids my son's age. I wish it would work for us and would buy a device for it if I could be sure it would run the app.

[dlech]

I just got a https://www.motorola.com/us/en/p/phones/moto-g/moto-g-power-2025/pmipmhi39mv?pn=PB640006US. The app was migrated from my old phone, so that might be how I circumvented the app store. However, looking at the app store (google play), it still says "works on your device".

[laurensvalk]

If the Boost app doesn't work, there is also the Powered Up app. This is LEGO's official general purpose app for boost/trains/technic, but it doesn't have all the missions and guided play activities. It could still be a good way to test that everything can work with your device. It should also be easier for younger audiences compared to Pybricks.

Based on the message you got for the Boost ("made for an older version of Android"), it does indeed sound like even though it could technically work on your device, LEGO just isn't updating it anymore. (This is what we're aiming to fix with Pybricks by the way, but unfortunately we don't have the same resources as LEGO make everything work and create all the content/activities too.)

[Eilderman]

Thank you. Indeed pybricks is a little complex for my 6-year-old so though we started with pybricks, we've mostly been using Scratch. Powered Up works as well. My problem now is to keep him from feeling that the set is a bust. If he can't actually use the guitar like we've seen in a video he may start to think the Boost is not as cool as I've been telling him it is (indeed as he thinks it is too). I have to try to get the model working the way it did in the App. I was hoping someone could describe the functionality to me so I could try to reproduce it or maybe someone had written their own code to make the guitar model functional.

[BertLindeman]

Hello,

The guitar takes the measurement(s) of the coror-distance sensor to determine the note to play.
The motor is used to simulate the plectrum moving over the strings.
Thinking simply:

• determine note depending on distance
• play note if the motor axle moves

The powered-up app has a very limited number of sounds that does not relate to a guitar.
Did not find a way to add custom sounds to powered-up.
Probably Scratch has better sounds.

Hope this helps a bit.

Bert

[Eilderman]

Thank you BertLindeman, that's exactly what I was looking for. Because we've been using Scratch, I wasn't aware the sensor was a distance sensor as well as a color sensor. That functionality isn't exposed in the Scratch interface. My theory was that the sensor might be sensitive enough to detect the reflection of the colored tiles in the white round 2x2 bring in the slider. Distance will be a lot easier.

My son was so frustrated tonight that I hadn't got the guitar ready that he tried to do it himself. I played him a couple of famous guitar riffs on YouTube and promised to let him play them on the Boost guitar and that seemed to mollify him for now.