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Here's another little project which I've finished recently. It's an automatic 8-to-1 Toslink switch.



Key features:

   
• powered through Mini-USB cable
• auto mode: new active inputs are automatically detected and selected. If there is more than one active input, you can use the tact button to cycle between the active inputs.
• manual mode: use the the tact switch to select the requested input. The selected input is stored and automatically loaded when the toslink switch is turned on.
• easter egg: hold the tact switch while turning on the toslink switch to make the LED's blink.

Schematic:


Gerber/HEX files:
Unfortunately I can't provide you with bare or assembled PCB's. But you can use the attached gerber files to order the PCB yourself. The PCB's dimensions are 70 mm x 50 mm.

The microcontroller on the PCB has to be flashed with the appropriate HEX file (also attached to this post), or the toslink switch won't work at all. The fuse bytes don't need to be altered. (Factory-set fuse bytes: Low Byte = 0x62; High Byte: 0xDF)

Please keep in mind that the gerber files and the hex file are intended for your personal, non-commercial use only!

Parts list:
You might have a hard time sourcing the needed parts, especially the Toslink receiver and transmitter sockets. Anyways, here's a list of the parts needed with german shopping links.

Qty	Name in schematic	Description	Package	Where to buy (in Germany)
1	IC1	Atmega48A microcontroller	TQFP32	http://www.reichelt.de/?ACTION=3;ARTICLE=121828;GROUPID=2959;PROVID=2794&wt_mc=amc14291660253544&zanpid=2107875674806510592
1	IC2	SN74CBT3251 1:8 Mux	TSSOP16	https://www.conrad.de/de/logik-ic-multiplexer-demux-texas-instruments-sn74cbt3251pwr-fet-multiplexerdemux-einzelversorgung-tssop-16-1073668.html
11	C1 - C11	100 nF ceramic capacitor	0805	http://www.reichelt.de/Vielschicht-SMD-G0805/X7R-G0805-100N/3/index.html?ACTION=3&GROUPID=3165&ARTICLE=31879&OFFSET=500&WKID=0&
1	C12	100 uF electrolytic capacitor	pitch: 2,5 mm diameter: 6 mm	https://www.reichelt.de/Elkos-radial-105-C-1000-5000h/RAD-FC-100-16/3/index.html?ACTION=3&GROUPID=4000&ARTICLE=84617&START=0&OFFSET=500&WKID=0&
9	RL1 - RL9	330 Ohm resistor	0805	https://www.conrad.de/de/dickschicht-widerstand-330-smd-0805-0125-w-1-100-ppm-samsung-electro-mechanics-rc2012f3300cs-rc2012f331cs-1-st-441762.html
1	RRST	10 kOhm resistor	0805	https://www.conrad.de/de/dickschicht-widerstand-10-k-smd-0805-0125-w-1-100-ppm-samsung-electro-mechanics-rc2012f1002cs-rc2012f103cs-1-st-439073.html
8	LED1 - LED8	red SMD LED	0805	https://www.reichelt.de/SMD-LEDs-Standard/SMD-LED-0805-RT/3/index.html?ACTION=3&GROUPID=3035&ARTICLE=31435&START=0&OFFSET=500&WKID=0&
1	LED9	green SMD LED	0805	https://www.reichelt.de/SMD-LEDs-Standard/SMD-LED-0805-GN/3/index.html?ACTION=3&GROUPID=3035&ARTICLE=31436&START=0&OFFSET=500&WKID=0&
8	IN1 - IN8	Sharp GP1FA551RZ Toslink receiver	-	http://www.pollin.de/shop/dt/MjMyODQ1OTk-/Bauelemente_Bauteile/Mechanische_Bauelemente/Steckverbinder_Klemmen/Toslink_Receiver_SHARP_GP1FA551RZ.html
1	OUT	Sharp GP1FA551TZ or PL131 Toslink transmitter	-	http://www.pollin.de/shop/dt/MDQxODQ1OTk-/Bauelemente_Bauteile/Mechanische_Bauelemente/Steckverbinder_Klemmen/Toslink_Transmitter_SHARP_GP1FA551TZ.html or https://www.conrad.de/de/ir-transmitter-650-nm-sonderform-everlight-opto-plt-131t112-156403.html
1	S1	DIP switch	-	http://www.pollin.de/shop/dt/MDYyOTc1OTk-/Bauelemente_Bauteile/Mechanische_Bauelemente/Schalter_Taster/DIP_Schalter_RP_02_B_10_Stueck.html
1	S2	tact switch	6 mm x 6 mm	https://www.reichelt.de/Kurzhubtaster/TASTER-9303/3/index.html?ACTION=3&GROUPID=3278&ARTICLE=44583&START=0&OFFSET=500&WKID=0&
1	PWR_SW	Apem 5236WWA-7 toggle switch	-	http://www.pollin.de/shop/dt/MDAyOTc1OTk-/Bauelemente_Bauteile/Mechanische_Bauelemente/Schalter_Taster/Miniatur_Kippschalter_APEM_5236WWA_7_ON_ON.html
1	USB1	SMD Mini USB socket	-	https://www.reichelt.de/USB-Einbauverbinder/USB-BWM-SMD/3/index.html?ACTION=3&GROUPID=6859&ARTICLE=52003&START=0&OFFSET=500&WKID=0&
1	-	adhesive rubber feet	diameter: 8 mm	http://www.pollin.de/shop/dt/MjkxODU1OTk-/Bauelemente_Bauteile/Mechanische_Bauelemente/Montagematerial/Gummi_Geraetefuesse_3_Groessen_46_teilig.html

More informations:
On the german circuit-board forums you can find another thread covering this Toslink switch: http://circuit-board.de/forum/index.php/Thread/19096-8-fach-Toslink-Switch-mit-automatischer-Umschaltung/

That is really quite cool, thanks for sharing it. 

Thanks! 

It's kinda strange that there aren't any cheap automatic Toslink switches available as detecting an active source is quite easy.

In case someone wants to know how the detection works:
When there's no active source connected to the Toslink receivers, then the output level of the receivers will be uncertain. It could be 0V or 5V. (Or even toggle at some point.) But IF there's an active source connected, the receiver's output will toggle all the time.

By using the microcontrollers pin change interrupt capability it's convenient to detect if the Toslink receiver's ouput has been toggled. Just wait a certain time (currently 200 us) and check the appropriate flag. If there really has been a change, a counter gets incremented. Repeat the procedure a number of times (currently 50 iterations). After that the counter is evaluated. If the counter is above a certain threshold (currently 70% => 0.7 * 50 iterations = 35), then this Toslink input is treated as active.

Wow, this is really great!

I haven't checked the forum post you've linked yet (my faith in online translators is small) - what device did you use to flash the hex file?