Build
Posted: Mon Aug 07, 2023 3:08 pm
Gosh. I appear to have worked out how to add images. Bit big, but they're there
So this is the finished build - Mk4 in the end, and I think the final take. It may look a sprawling mess, but that kit fits in the Ryanair cabin bag which can be worn over the shoulder, and I can take a walk in the mountains wearing the gloves. It has 2 battery packs - a 12v pack for the 4 channel power amp and a 2 socket 5v for the Raspberry Pi 3 and the HDMI Dolby 5.1 extractor
The (2nd hand) raspberry Pi plays a 2 hour 6 channel .ac3 file using Vimeo. It has a cheap touch screen fitted which I can't calibrate, so it is just a screen, and I use a wireless usb mouse to launch the music. The file is generated by code written by a friend, which produces a 4 channel WAV (which is enormous). That is imported into Audacity, where 2 blank channels are added, and the 4 active channels are assigned to FL FR RL RR. The file is then converted to ac3 using SOX.
Since the Pi outputs audio by HDMI - the Dolby 5.1 extractor was a compact sound card option. 4 RCA's link to the 4 channel 50W class D amp, which in turn feeds a box which adds a 47 ohm resistor in series to each channel to give more range on the pots, and protect the 3w exciters from accidental damage.
RJ45 sockets and leads are used for the connections. 8 way solderless, screwless modular junction blocks on a custom mount, make removal of the exciters for servicing and installation simpler. It also allows configurable lead arrangements. At the moment I have 2x1.5m ethernet cables, but I will get a 2m cable and have 1.5 m on the side nearest the bag, and 2m on the furthest from the bag
So this is the finished build - Mk4 in the end, and I think the final take. It may look a sprawling mess, but that kit fits in the Ryanair cabin bag which can be worn over the shoulder, and I can take a walk in the mountains wearing the gloves. It has 2 battery packs - a 12v pack for the 4 channel power amp and a 2 socket 5v for the Raspberry Pi 3 and the HDMI Dolby 5.1 extractor
The (2nd hand) raspberry Pi plays a 2 hour 6 channel .ac3 file using Vimeo. It has a cheap touch screen fitted which I can't calibrate, so it is just a screen, and I use a wireless usb mouse to launch the music. The file is generated by code written by a friend, which produces a 4 channel WAV (which is enormous). That is imported into Audacity, where 2 blank channels are added, and the 4 active channels are assigned to FL FR RL RR. The file is then converted to ac3 using SOX.
Since the Pi outputs audio by HDMI - the Dolby 5.1 extractor was a compact sound card option. 4 RCA's link to the 4 channel 50W class D amp, which in turn feeds a box which adds a 47 ohm resistor in series to each channel to give more range on the pots, and protect the 3w exciters from accidental damage.
RJ45 sockets and leads are used for the connections. 8 way solderless, screwless modular junction blocks on a custom mount, make removal of the exciters for servicing and installation simpler. It also allows configurable lead arrangements. At the moment I have 2x1.5m ethernet cables, but I will get a 2m cable and have 1.5 m on the side nearest the bag, and 2m on the furthest from the bag