Noob question - how to wire up potentiometer&buttons

5grandpint

Hi i have bought a bela board, this is my first time trying to do any electronics/breadboard stuff. Obviously bela is very new so i am struggling to find tutorials on how to wire buttons and potentiometers up with it on youtube but there are many on arduino. Is it pretty much the same in terms of electronics? Can anyone recommend some very simple basic resources on wiring up knobs and buttons to a bela board or some great basic electronics in general tutorials.. kind of struggling to get started with this.

Thanks in advance

bela_robert

Hi, great that you are getting into Bela and electronics – it's a deep dive but definitely worth the effort!

A good place to start would be our experimenter kit guide which has many circuits and code for different types of sensors. You can find that here: https://github.com/BelaPlatform/Bela/wiki/BelaBook.pdf

Note that some of the names of the examples that the guide refers to have changed but you will be able to find them all in the example folders of the IDE.

We will also be putting up a series of tutorials on building circuits and working with Pure Data in the next couple of weeks on learn.bela.io so keep an eye out for that.

Most circuit diagrams you will find for Arduino translate across to Bela directly but it is important to note that you should only work with 3.3V when using the digital pins on the two side headers otherwise you risk damaging the board. It's generally best to avoid using the 5V on the board unless you really need it as most circuits will work fine with 3.3V.

You may also be interested in our YouTube course on C++ for Real-Time Audio Programming which is currently just over half way through with lectures coming out every week. Many circuits are discussed in the lecture so that's also a good place to gain an in depth knowledge of the electronics and the programming to interact with the circuits.

You can find the course here: https://www.youtube.com/playlist?list=PLCrgFeG6pwQmdbB6l3ehC8oBBZbatVoz3

5grandpint

bela_robert thanks a lot! I have a lot to learn in terms of circuits/electronics etc. so looking forward to those videos! Will definitely dive into some of these other resources in the meantime, thanks!

Just a quick much more specific question if you wouldn't mind clearing this up for me, can bela work with external batteries, say AA batteries for example, instead of working on usb power?

Thanks

giuliomoro

We'd normally use USB batteries as those you'd use for portable mobile phone chargers. You could in principle stack 3x 1.5V AAA batteries, but when their voltage drops below the nominal 4.5V (as it will do when discharging), the analog inputs will start misbehaving. More info here.

5grandpint

giuliomoro thanks again, I just have one more question, as I have had a go at the first circuit in the experimenter book, with the button and the LED, and I appear to have done something wrong. Although I have checked my wiring a lot of times and it is definitely as shown in the diagram. The only thing is that my breadboard appears to be the other way around than the one in the diagram. I am unsure if this makes any difference. I just wanted to check, is the red cable from the bela going into the positive on the breadboard?

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Thanks

giuliomoro

Can you show a picture of your wiring and tell me exactly which example you are using?

5grandpint

giuliomoro Hi it is the digital input example.. It is now kind of working. I took everything out and had another go from the beginning, the only issue I'm having is that in the example, it says the LED should stay off normally and only come on when the button is pressed. For me, it is the other way around so that the LED is on all the time and only going off when I press the button. Sorry if the picture is not very good, my camera on my phone is broken so could only take with front facing camera.
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Thanks

5grandpint

giuliomoro 5grandpint here is another pic of the wiring. As i said it appears to be doing opposite of what it id supposed to as the LED is remaining on normally and only turning off when button is pressed down.
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giuliomoro

I can't see well in the pictures, but I looked at the code and it looks like the documentation is wrong and the behaviour you are observing is the expected one. Digital pin 1is connected to 3v3 through the resistor at all times. This means that while the button is not pressed, it will read high and when the button is pressed, digital pin 1 will be connected to ground, and will read low.

We will fix the documentation, thanks for raising the issue.

5grandpint

giuliomoro brilliant! that means I had it wired up correctly the second time then. Thanks again so much. The support for everyone especially beginners here at Bela is absolutely fantastic I've noticed. Thank you to all the Bela team for such great work!

giuliomoro

glad to hear you're finding a good environment here!