Request: How to read data from 3.5mm Jack reddit / freebsd ---------------------------------------------------------------------- mosttrash · 2023-04-07 08:39 I have an under desk exercise peddle bike. The bike communicate with a desktop counter via a cable with a 3.5mm Jack each end. I'd like to read the communication data into the Freebsd. I figure if Freebsd can read data from a microphone, it might be able to get some form of data from the bike. Freebsd 13 is installed on bare metal. There are a selection of 3.5mm jacks on the motherboard, including mic and line-in ports Is there a way to dump a audio jack data to a file, or a stream? Or perhaps read into a python script? ---------------------------------------------------------------------- TrevorSpartacus · 2023-04-07 08:56 Seriously? Don't plug random shit into your motherboard. Your bike isn't sending data via audio signal at mic or line level and just uses 3.5 mm jack for serial communication. Poke it with a scope. ---------------------------------------------------------------------- [deleted] · 2023-04-07 09:00 [deleted] ---------------------------------------------------------------------- mosttrash · 2023-04-07 09:51 Thanks for your concern, and for your warning to take caution I've not plugged anything in at this stage. But I am interested in whether I could theoretically harvest data. Also, "poke with a scope" is great advice - I'd not considered doing that ---------------------------------------------------------------------- mosttrash · 2023-04-07 10:05 Thanks for your reply I have a rpi on hand, it shouldn't be too hard to read and maybe decipher the data the bike is sending. Although, probing first to be sure voltages don't pop this io might be prudent. 25 years ago in the engineering degree we captured generated sine waves with PC and IO PCI card. I've not done anything similar since. Wondering if I could capture data with the on-board sounds card was an off chance at best ---------------------------------------------------------------------- Super-Cookie1884 · 2023-04-07 10:50 Once I used audacity for getting data from my IR tv remote control and then moved that data to the phone with IR. ---------------------------------------------------------------------- [deleted] · 2023-04-07 17:35 Make sure to check the voltage of the data connection before plugging it into your RPI! 3.3 and 5v are most common, but it could be higher. It is unlikely but possible to have 1.4v, common with some digital data busses on low powered devices. The best place to check would actually be on the treadmill board itself. Trace the data out pen to a micro controller. Look at the operating voltage of the micro controller and see if there's any voltage dividing equipment. ---------------------------------------------------------------------- o0xh · 2023-04-07 19:42 >The bike communicate with a desktop counter What is the "desktop counter" is that a dedicated hardware gadet that came with the pedals? ---------------------------------------------------------------------- mosttrash · 2023-04-07 20:44 Yup, the desktop display came with the pedals. ---------------------------------------------------------------------- KookyWait · 2023-04-08 00:52 These days there are various scopes (mostly FPGA driven) that will hook up to your machine over USB and be an option for capture as well. So choose your scope well, and it might be your solution to both (probably not if you want to continuously get telemetry from the bike - a scope is too expensive for that!)