[Bug] Infraredsensor non lego

[20100Lego]

Describe the bug
What is the problem?
I'm doing some advanced programming with Pybrick (thanks to you!) like a GBC module that writes text with the ball.
I saw that the infrared sensor has a class for measuring brightness. I bought a non-Lego infrared sensor (Aliexpress), it works as a distance sensor in the poweredup application. In pybricks if I do sensor = InfraredSensor (Port.A), the script blocks and doesn't go any further, it doesn't output as an error.
Do you think it's possible to integrate these sensors to make them pybricks compatible?
I'm a computer scientist, I can do tests to determine what the sensor returns on initialisation if you provide me with debugging/testing tools.
It would be great if it worked!
Thanks in advance!

To reproduce
Steps to reproduce the behavior:

1. Connect an unofficial Infraredsensor sensor
2. Try to connect sensor = InfraredSensor (Port.A
3. Script does not go ahead

Expected behavior
What did you expect to happen instead?
Sensor sends value

Screenshots
There is a saying that a picture is worth a 1000 words. Screenshots really help to identify and solve problem

[dlech]

You should try using the same class for the same LEGO sensor that works in the official LEGO app, which I assume since you said "distance" sensor would be ColorDistanceSensor().

[laurensvalk]

I bought a non-Lego infrared sensor (Aliexpress) (...) if I do sensor = InfraredSensor (Port.A), the script blocks and doesn't go any further, it doesn't output as an error.

It is likely that this sensor doesn't implement the LEGO communication protocol quite right.

Do you think it's possible to integrate these sensors to make them pybricks compatible?

Probably. We've been busy enough getting all the official stuff to work, so we haven't gotten around to some of the third party devices.

I'm a computer scientist, I can do tests to determine what the sensor returns on initialisation if you provide me with debugging/testing tools.

Where you ordered the sensor, you can probably also order a spare cable that you can cut and wire up to a TTL/USB cable. Combined with a custom built firmware, you will then be able to monitor exactly where it gets stuck.

If this sounds like a fun challenge, let me know and we can provide some instructions 😄

[20100Lego]

Thank you for your answers!
I'll try to test the other classes this weekend.

I realised that Lego no longer sold colour sensors, so I wanted to try a third-party sensor.

Yes, I can imagine that it's already quite a job to implement the whole Lego suite.
If I have to analyse and provide you with the information you need to develop pybrick, I'm all for it!

I ordered a female pup plug and a usb ttl adapter, otherwise I must have an Arduino somewhere.
If you can tell me how you analyse what the sensor sends back, that would be great.
Thanks a lot

[laurensvalk]

I was actually thinking of the plug the other way around, but both approaches can be useful.

When you power the sensor on, it should begin sending data on the UART pins with lots of information about what the sensor can do, so that could be a good place to start. No need to connect any hubs for this side of the story. (It's in the picture just so you can see which side of the cable/connector is up.)

• P1 and P2 are motor wires that are not applicable here.
• P3 is GND.
• P4 is 3.3V.
• P5 is UART TX as seen from the hub (sensor UART RX)
• P6 is UART RX as seen from the hub (sensor UART TX)

The other interesting part would be the hub side. We can enable some debugging info in the firmware and potentially see where it gets stuck. Let's do that when we get there.

[laurensvalk]

Since you've looked into it, do you know if there is one major party producing such sensors or is it more likely a mix with potentially lots of different and incompatible versions?

[dkBrazz]

I have the same issue with Infrared Sensor

I have a WeDo 2.0 replica, which works fine with official WeDo app
I have an original cargo train set with CityHub

I try to use WeDo replica components with original CityHub

DC Motor replica works fine with both PoweredUp app and Pybricks

Infrared Sensor works with PoweredUp application - I can read IR sensor with the CityHub and use it in program
In Pybricks script freezes on calling InfraredSensor() constructor - no exception, just freeze until you stop the execution
Infrared Sensor successfully detects as "Wedo 2.0 Infrared Motion Sensor" with detect script from here https://docs.pybricks.com/en/stable/iodevices/pupdevice.html
I suppose it might be the same issue as @20100Lego reported

Any hints how I can provide you any debug info?

Another story with the tilt sensor
I couldn't get it work with CityHub at all - it does not read with both PoweredUp and Pybricks, while working fine with WeDo app
PoweredUp just ignores/reads nothing from it
Pybricks throws ENODEV when instantiating a class

[dlech]

Pybricks uses some different sensor modes to improve the precision compared to the official LEGO software. So it is possible that the 3rd party sensor only implemented the modes that the LEGO software uses and not all of the other modes.

If you have a logic analyzer, you could use that to monitor the UART communications to see what is actually going over the wire. Then we can compare what the official LEGO software does compared to what Pybricks does.

Also, you should be able to use these sensors with the LUMPDevice() class to have full control over them. This would let you use the same modes that the official LEGO software uses even if the other Pybricks classes don't use them.

[nuno2500]

Hi,

Same problem with me. Thats ok. When I bought the sensor, I already knew that maybe wouldn't work and could be used in another way. Is it possible to use P1 to P4 to power any motor, LED, or even an electromagnet? The maximum amperage and voltage could be limited to avoid frying the hub. What do you think?

Best Reagards,

Nuno Caravaca

Portugal

[dlech]

There is some info on https://bricks.stackexchange.com that shows what is inside the hubs, for example for the City Hub: https://bricks.stackexchange.com/a/10258/3498

Here you can see the motor controller chip and there is also a fuse that limits the current from the battery. So you can us this info to determine if it will work with whatever electronics you dream up.

But in general, yes you could hook up anything that can run off of battery power to P1 and P2. You just have to be careful about the polarity.

[nuno2500]

There is some info on https://bricks.stackexchange.com that shows what is inside the hubs, for example for the City Hub: https://bricks.stackexchange.com/a/10258/3498

Here you can see the motor controller chip and there is also a fuse that limits the current from the battery. So you can us this info to determine if it will work with whatever electronics you dream up.

But in general, yes you could hook up anything that can run off of battery power to P1 and P2. You just have to be careful about the polarity.

Thanks for your tip but how can i send voltage to P1 and P2 with PyBricks code? I do use coding by watching the exemples in the PB docs.

Best Regards

Nuno

[dlech]

You can use the DCMotor() class to do this.

[nuno2500]

You can use the DCMotor() class to do this.

Thanks. I also found the wiring here:
https://www.eurobricks.com/forum/forums/topic/162288-powered-up-a-tear-down/

Best Regards and thanks for PyB.

Nuno