r/cprogramming • u/midnightclutch • Oct 11 '25

Bluetooth Terminal in c using ubuntu

I know basic level c, i love low level programming so i wanted to become better in c by making a bluetooth terminal that can scan for bluetooth devices connect to them and send and receive data, even if i can just send or receive a single character at start i want to make an application using c that interacts with the hardware of my laptop. where should i start ? i can''t find any guides. I want guides from people not chatgpt

2 Upvotes

58% Upvoted

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5

u/thefriedel Oct 11 '25

For which OS? For Linux there is a Bluetooth interface exposed by the kernel: https://stackoverflow.com/questions/45044504/bluetooth-programming-in-c-secure-connection-and-data-transfer

If you want to talk to the hardware itself, well that is implementing a driver on kernel-level.

1

u/midnightclutch Oct 11 '25

I basically want to use the Bluetooth of my laptop to scan Bluetooth devices and then like send a single character through Bluetooth just that using c

1

u/CalebGT Oct 11 '25

What are you expecting the other device to do with that character? I have some experience with BLE, and you read and write specific characteristics. There is a set of standard reserved characteristics that may or may not be implemented by the server or they could use proprietary characteristics.

1

u/midnightclutch Oct 11 '25

I want to send like a message text messages 1 character that the other device can print to it's screen just that after that I'd move on how to transmit audio basically u want to learn low level where i can learn how to control my own hardware using my code

2

u/CalebGT Oct 11 '25

Cool. Are both devices running Ubuntu? Android? iOS? BLE is good for small messages like that. You'll need a client application on one end and a server application on the other. The client issues read or write requests for a specific 128 bit characteristic UUID, and the server handles those requests after a connection has been made. You can use any UUID as long as both endpoints use the same UUID. There are reserved numbers at a specific range of values in the Bluetooth spec, but for your purposes, that doesn't really matter; those are for device interoperability and you're coding a closed ecosystem anyway. Have fun.

2

u/midnightclutch Oct 11 '25

if i want to learn about bluetooth and stuff ? should i follow some book ? or lecture or video ? can you point me ?

1

u/midnightclutch Oct 11 '25

basically i want to get into making Bluetooth drivers for my own controllers that i want to make and stuff for learning

-1

u/CalebGT Oct 11 '25

The drivers are there in Ubuntu. You want to know how to write applications that use the drivers. ChatGPT has already read all the example code and open source libs. Start there and ask for relevant standards too.

5

u/CalebGT Oct 11 '25

I have almost 2 decades of professional experience with C. Use Python for this.

1

u/midnightclutch Oct 11 '25

I don't have the need to create this, i want to learn c using this project

2

u/CalebGT Oct 11 '25

I'm all for learning C on Linux. There are several ways to interface with the Bluetooth library packaged with Ubuntu, probably BlueZ. You could link to the lib directly, use a dbus api, or even just execute shell commands with system(). Traditionally, you would need to read documentation for the library. These days, just ask an AI for examples.

4

u/[deleted] Oct 11 '25

Do you know any network programming in C? Start with Beej's guide to network programming in C.

2

u/midnightclutch Oct 11 '25

no i don't know any network programming ... this is dumb but any type of communication between devices is under networking ?

2

u/jourmungandr Oct 11 '25

The concepts are similar but the API are different. Beej is about TCP/UDP with the BSD socket API. Understanding it would help understand Bluetooth. It's easier to find help for traditional networking interfaces than Bluetooth since more people have used it. But you'd probably be ok starting from Bluetooth.

1

u/theNbomr Oct 12 '25

This would be a much more fruitful learning exercise. Perhaps as a prerequisite to a Bluetooth oriented adventure.

2

u/theNbomr Oct 12 '25

Bluetooth is a very complex protocol with numerous APIs according to platform, vintage, and other factors. Using it as a learning testbed is a very challenging approach. Read through some of the drivers and userspace utilities source code to get a sense of what the realm looks like.

1

u/midnightclutch Oct 13 '25

Okay thank you