Cheap 3D printable fiber optics

[Netzpfuscher]

I'm working for a while now at a cheap alternative to expensive fiber optics for the UD3. I don't like parts out of unobtainium ^^

The HFBR versatile link series from Broadcom / Avago /HP is very nice, it uses plastic fibers which can assembled without special tools (Only fine sandpaper is needed for polishing). The connectors and the fiber are cheap, but the transmitter/receiver pair costs about 30€.

I designed a 3D printable housing for the optics out of Toslink transmitter / receiver.

Opening a Toslink like this:


You find these chips:


These can be put in the 3D printed Housing:




And connected to the Versatile Link connector:



I upload the design files after finishing small changes. Print time is around 12 minutes at 70mm/s with 100% infill. The costs for the optics are around 1€ or less if you find some in the junk.

[Laci]

Great to hear about some cheap fiber optic solutions.
I had a hard time recently choosing a suitable kit. From the versatile link series two HFBR-1531Z transmitters and two HFBR-2531Z receivers turned out to be the cheapest with a 10m long duplex cable with latching connectors, for around 50 USD including shipping.
I saw some gigabit interface converters for around 5 USD, like this:



They should work with cheap patch fiber cables, but I have no idea what additional parts are required to convert serial data to their communication method. Perhaps somebody used something like this before and knows if this works?

Are these similar to the toslink you disassembled? They are cheap tho...   If they are good for the purpose, do you know what type of connector/fiber cable they work with?

https://www.tme.eu/en/details/fcr6842032r/optical-connectors/cliff/orj-3-fcr6842032r/
+++
https://www.tme.eu/en/details/fc6842032t/optical-connectors/cliff/otj-3-fc6842032t/


https://www.tme.eu/en/details/fc684208t/optical-connectors/cliff/otj-8-fcr684208t/
+++
https://www.tme.eu/en/details/fc684208r/optical-connectors/cliff/orj-8-fcr684208r/


https://www.tme.eu/en/details/fc6842135tr/optical-connectors/cliff/

[dexter]

I had the same price issue with HFBR's when i first moved to DRSSTC's so i tried TOSLINK. Bought a pair of FCR6842032T and R and a TOSLINK optical cable. Maybe breadboard testing wasn't the best idea but i couldn't get them to work. For some reason the output of the receiver could  maintain a stable logic level HIGH for only a few hundreds of ns after which only noise. Tried everything pull up/down resistors comparator bought new receivers and nothing.

In the end i found some OPF2414 receivers on ebay for ~4$ bought a ST Fiber Optic Connector used it to modify the TOSLINK optical cable, replaced the TOSLINK transceiver IC with a high flux red LED and added a LM311 after the OPF2414 because its output was to small (i made my own UD pcb's so adding one more comparator wasn't an issue) and everything works.
Basically from the initial TOSLINK set i only used 1 transceiver (just the plastic part) and the cable which i also modified by changing the connector to a ST connector.


"do you know what type of connector/fiber cable they work with?"
https://www.tme.eu/ro/en/details/avk-216-0200/audio-video-cables/goobay/50447/

[Netzpfuscher]

@Laci
The SFP fiber modules are not easy to drive (differential low voltage logic if you need to buy a level converter you are around 5€ each). They are designed for >100 MHz / > 1 GHz. I have read that they maybe work with a 10 MHz signal. But the Signal needed to be DC free because of AC coupling within the module.
Driving the laser diode without the electronics in such a module should be no problem, but the receiver is more complicated. It's a naked photodiode, you need a little bit of circuitry to amplify the signal.

@Dexter
The most Toslink receivers are AC coupled and have a automatic gain control and specified for >100kHz. The interrupter signal of a normal DRSSTC has a lot of DC ~90% and a low frequency. This is not the case for the UD3 it's a normal UART, not DC free, but a lot faster >500 kHz to 2 MHz and a error detection can be enabled. If a data packet gets corrupted its no big deal. But in my test with 500 kBit there were no CRC errors.