![\"\"](\"https:\/\/www.scottdanesi.com\/wp-content\/uploads\/2018\/05\/pbl_a-16908_emitter-150x150.jpg\")
<\/a>Opto transmitters are nothing more than high powered infrared LEDs.\u00a0 For this guide, I am going to be referring to the Williams\/Bally style opto transmitter which can be seen here: https:\/\/www.pinballlife.com\/williamsbally-led-transmitter-emitter-for-opto-assemblies.html<\/a>.\u00a0 This LED emitter has no circuitry attached to it by default.\u00a0 These LED emitters are also used on the small PCB and bracket assemblies seen here: https:\/\/www.pinballlife.com\/williamsbally-led-transmitter-emitter-and-pcb-board.html<\/a>\u00a0and other various trough board assemblies.<\/p>\nIn order to safely power this LED, you will need to gather a few data points and make a couple small decisions.\u00a0 You will need to know the forward voltage of the LED, maximum constant current that the LED can handle, decide what input voltage you would like to supply to it (5v or 12v), and decide how much current you would like to give the LED to ensure it has enough power to transmit infrared light to reach your opto receiver.<\/p>\n
So here is our data:<\/p>\n
- \n
- Forward Voltage:<\/strong><\/span> 1.7v<\/li>\n
- Max Constant Current:<\/strong><\/span> 100ma, but I recommend you do not exceed 75ma to maximize the life of the LED.\u00a0 This will be powerful enough to transmit a pretty decent amount of distance between the emitter and receiver.<\/li>\n
- Input Source Voltage:<\/strong><\/span> 5vdc is my recommendation as it is higher than the forward voltage of the LED, and low enough that the resistor does not have to dissipate too much heat.<\/li>\n<\/ul>\n
These LED emitters will need a current limiting resistor in series with them as applying 5v or 12v directly to the LED will cause it to overload and fail.\u00a0 Now, to calculate this resistor value, we will need to calculate resistance and power based on the data that we have.\u00a0 Now, I could be idealistic and talk about the actual calculations, but I am going to show you how I usually calculate this using an online LED resistor calculator.\u00a0 The one that I use the most is the one below.\u00a0 I have already filled out the fields, but feel free to change some of the values up to see what happens.<\/p>\n
http:\/\/led.linear1.org\/1led.wiz?VS=5;VF=1.7;ID=75<\/a><\/p>\n
![\"\"](\"https:\/\/www.scottdanesi.com\/wp-content\/uploads\/2018\/05\/LEDEmitterResistorCalc.jpg\")
<\/a><\/p>\nSo as you can see above, the calculator has automatically figured out what the ohms and recommended resistor wattage should be for our emitter.\u00a0 What I also like about this calculator is that it gives a nice visual representation of how to wire the circuit and what the resistor color bands are.<\/p>\n
Important note:<\/strong> <\/span>Please be sure to use at least the recommended resistor wattage.\u00a0 You can see above that the calculator is recommending at least a 1\/2 watt resistor.\u00a0 Too small of a resistor and it can burn up, which is bad.\u00a0 \ud83d\ude42<\/p>\n
That is about it for powering an opto emitter!<\/p>\n
Connecting Opto Receivers to the SW-16 P-ROC Board<\/h2>\n
![\"\"](\"https:\/\/www.scottdanesi.com\/wp-content\/uploads\/2018\/05\/pbl_a-16909_receiver.jpg\")
<\/a>Now for this section, I am going to be talking about the Williams\/Bally style opto receivers and how they hook up to the SW-16 P-ROC switch boards.\u00a0 These are the black colored opto receivers that can be fond here: https:\/\/www.pinballlife.com\/williamsbally-led-receiver-for-opto-assemblies.html<\/a>.\u00a0 These, just like the emitters, are also used in small PCB assemblies, and trough opto boards as well.<\/p>\nTo connect these optos into the SW-16 P-ROC board, you will simply need to wire it directly to the inputs of your switch board.\u00a0 It is really that easy.\u00a0 It will act just like a standard switch as long as it is connected in the correct orientation.\u00a0 Below, you will see an image from the P-ROC documentation.\u00a0 The cathode\/ground side of this diode is the side with the flat indentation on the black epoxy base of the opto.\u00a0 Please also keep in mind that opto receivers are normally closed switches and when it detects the IR beam from the emitter, it will open.\u00a0 This is opposite of a normal switch.\u00a0 When a ball breaks the opto beam it will go from a closed state to an open state.<\/p>\n
The full documentation can be found here:\u00a0https:\/\/www.multimorphic.com\/content\/uploads\/2017\/07\/SW-16-2_LLD_v2-0.pdf<\/a><\/p>\n
- Max Constant Current:<\/strong><\/span> 100ma, but I recommend you do not exceed 75ma to maximize the life of the LED.\u00a0 This will be powerful enough to transmit a pretty decent amount of distance between the emitter and receiver.<\/li>\n
![\"\"](\"https:\/\/www.scottdanesi.com\/wp-content\/uploads\/2018\/05\/LEDReceiverHookups.jpg\")
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