{"id":25980,"date":"2022-10-16T22:27:18","date_gmt":"2022-10-16T21:27:18","guid":{"rendered":"https:\/\/www.pinballnews.com\/site\/?p=25980"},"modified":"2024-01-23T10:17:34","modified_gmt":"2024-01-23T10:17:34","slug":"new-ir-pinball-testers-part-one","status":"publish","type":"post","link":"https:\/\/www.pinballnews.com\/site\/2022\/10\/16\/new-ir-pinball-testers-part-one\/","title":{"rendered":"NEW IR PINBALL TESTERS: PART ONE"},"content":{"rendered":"\n

Infrared (IR) transmitters and receivers are vital components used in many electronic pinball machines since 1987. Commonly referred to as ‘opto-switches’ or simply ‘optos’, paired-up transmitters and receivers allow contactless sensing of movement in order to register a target hit, detection of a ball’s position or the sensing of movement by a mechanical device.<\/p>\n\n\n\n

However, useful as these components are, they do have one characteristic which makes it difficult to troubleshoot them (or the circuit of which they form a part). The infrared light they either transmit or sense is usually invisible to the human eye.<\/p>\n\n\n\n

That makes it tricky to tell whether an IR transmitter is radiating as intended, and whether an IR receiver is detecting IR radiation correctly.<\/p>\n\n\n\n

Back in 2006, Todd Andersen of Pinball Renaissance in Minnesota wrote an article describing how to build your own matching IR transmitter and IR receiver to aid with testing. When the associated button is pressed, these car-fob-sized devices would either transmit a constant IR beam, or light an LED to indicate the detection of IR radiation, thus allowing you to diagnose faults with both IR transmitters and receivers.<\/p>\n\n\n\n

While extremely useful and functional, much has changed in the world of electronics in the past sixteen years. The availability of the component parts has changed as has the cost, while newer methods have become easily afforded.<\/p>\n\n\n\n

So, Todd has looked anew at the problem and devised an alternative, automated, more modern and more readily-available alternative you can build at home.<\/p>\n\n\n\n

In this first article he looks at the hardware used in his design, how the components are chosen, and includes links to the components’ suppliers for more information, while the second part concentrates on the software needed, providing code you can use immediately or modify to your own requirements.<\/p>\n\n\n\n

Over to Todd…<\/p>\n\n\n\n

\n\n\n\n

Having previously put myself in your shoes, I\u2019ll summarise two of my main reasons for deciding an earlier Pinball News article<\/a> about building your own IR testers possibly needed an update…<\/p>\n\n\n\n

    \n
  1. First and foremost, soldering<\/a>.<\/strong>
    \u2022 Many people can\u2019t solder.
    \u2022 Many people don\u2019t want to solder.
    \u2022 With this new version, connections can be simply wrapped and hot glued, or even bolted in place.<\/li>\n\n\n\n
  2. Technology is changing.<\/strong>
    \u2022 Modern computers (post-2015) do always not play nicely with Arduino devices.
    \u2022 Microcontroller technology is now cheaper, smaller, more capable, and newer.
    \u2022 Software (sketches) can be easily modified for use with various board\/component combinations.<\/li>\n<\/ol>\n\n\n\n

    Pinball Renaissance sold a ‘fob’ version of the IR Tester sets – sender and receiver pairs – to pinball hobbyists. These testers were built using discrete electronic components and sold out some time ago.<\/p>\n\n\n\n

    While fulfilling a special request to make more, I noticed that I lacked enough discrete components to complete said order. At that point, I realised I could update the IR Pinball Testers from all-discrete electronic components, to use newer Arduino clone boards. <\/p>\n\n\n\n

    Most of the clone boards I had in stock were subsequently made into IR Pinball Testers. These new IR Testers are now sold out as well, with completion of this special request marking these new Arduino clone board based IR Tester sets as no longer available.<\/p>\n\n\n\n

    Using the Arduino clone boards to complete the special order significantly dwindled my stock of the specific microcontroller clone board I used. <\/p>\n\n\n\n

    When I shopped reputable mainstream retailers to try to purchase enough boards to replenish stock, I discovered two things. First, assuming in large part due to the global chip shortage, prices had over quadrupled. Second, and again I\u2019m assuming related to the assumed reason behind the first, boards were wildly out of stock. <\/p>\n\n\n\n

    This forced me to search even harder. In doing so, I discover I could purchase complete Attiny85 microcontroller-based boards for less than the cost of the Attiny85 microcontroller chips alone. <\/p>\n\n\n\n

    So, I decided to purchase these new-to-me Attiny85 based clone boards.<\/p>\n\n\n\n

    Tiny Boards<\/strong><\/span><\/p>\n\n\n\n

    To replenish my stock, I found the EDATtiny<\/a> from ElectroDragon<\/a>. These one inch diameter boards are designed to be ‘wearable’ and feature the ATtiny85 microprocessor, being programmable via the Arduino IDE software. <\/p>\n\n\n\n

    However, these Chinese clone boards had a 20% failure rate, although the manufacture did refund me for those failed boards.<\/p>\n\n\n\n

    Per the manufacturer, these red EDATtiny boards are, \u201cCompatible with lilytiny, digispark bootloader, to upload sketch please add board digispark 16.5mhz in arduino IDE.<\/em>\u201d<\/p>\n\n\n

    \n
    \"The<\/a>
    The top and bottom of the EDATtiny board<\/figcaption><\/figure>\n<\/div>\n\n\n

    As an alternative, the layout and board colours of the black and purple Lilytiny clone boards (shown below) are only cosmetic differences from the EDATtiny boards I used (shown above). These Lilytiny clone boards should otherwise be identical to the EDATtiny boards.<\/p>\n\n\n

    \n
    \"The<\/a>
    The Lilytiny ATTiny85 boards<\/figcaption><\/figure>\n<\/div>\n\n\n

    All three round boards are actually clones of Digispark square boards<\/a>. In fact, and as introduced earlier, DigiStump started it all with their Digispark boards. After all, they are, \u201cHome of the Digispark<\/em>.\u201d<\/p>\n\n\n\n

    For the price I found for the standalone ATtiny85 chips, I could purchase two complete EDATtiny boards. This included the same shipping and handling costs. <\/p>\n\n\n\n

    In addition to affordability, I noticed the use of holes and their spacing on these boards made connecting a few discrete electronic components quite easy. I realised this made these boards ideal for pinball hobbyists who may want to build their own IR Tester boards. And, the built-in\/onboard LED of the EDATtiny saves us from having to bother with even more discrete electronic components.<\/p>\n\n\n\n

    For those who want to try this at home, the few supporting discrete electronic components needed can be easily attached without soldering. The legs of these components can be wrapped in place and secured with hot glue. Or, the legs can simply be bolted in place if you prefer.<\/p>\n\n\n\n

    Discrete Components<\/span><\/strong><\/p>\n\n\n\n

    Here are the additional components you will need:<\/p>\n\n\n\n

    IR LED (Sender \u2013 880nm wavelength)<\/strong>
    Industry P<\/strong>art N<\/strong>umber (PN)<\/strong>: QED123
    Substitute PNs: QED121, QED122, 276-143, 276-143C
    Old WMS Pinball PN: A-16908
    (Note: Some pinball parts sellers may sell this component already mounted on a board.)<\/em>
    New WMS Pinball PN: 5671-12731-00
    (Note: This is usually sold as just the discrete component itself.)<\/em><\/p>\n\n\n\n

    \"Williams
    Williams Pinball IR LED (Sender \u2013 880nm wavelength)<\/figcaption><\/figure>\n\n\n
    \n
    \"IR<\/a>
    IR Transmitter specifications<\/figcaption><\/figure>\n<\/div>\n\n\n

    This diode has polarity. This means it can only operate correctly in circuit when placed in a specific orientation. The ANODE goes to the +5 Volt source on your ATtiny board; not the +5V pin.<\/strong><\/p>\n\n\n\n

    A 940nm wavelength side-looking version of this photodiode (PN: QEE113) can also be procured. It should<\/em> work in pinball machines and may be useful for getting into smaller spaces like the small slot in between opto-interrupters, as used on drop targets and flipper mechanisms. However, that photodiode has not been tested for use in this article.<\/p>\n\n\n\n

    IR Transistor (Receiver \u2013 880nm sensitivity)<\/strong>
    Industry PN: QSD124
    Substitute PN: 276-145 or 276-145A
    Old WMS Pinball PN: A-16909
    (Note: Some pinball parts sellers may sell this component already mounted on a board.)<\/em>
    New WMS Pinball PN: 5163-12732-00
    (This is usually sold as just the discrete component itself.)<\/em><\/p>\n\n\n

    \n
    \"Williams<\/a>
    Williams Pinball IR Transistor (Receiver \u2013 880nm sensitivity)<\/figcaption><\/figure>\n<\/div>\n\n
    \n
    \"IR<\/a>
    IR Receiver specifications<\/figcaption><\/figure>\n<\/div>\n\n\n

    This transistor also has polarity. That means it can only operate correctly in circuit when placed in a specific orientation. The COLLECTOR (non-flat side) goes to the +5V pin on your ATtiny board.<\/strong><\/p>\n\n\n\n

    A side-looking version of this NPN phototransistor (PN: QSE113 or QSE114) can also be sourced. It may <\/em>be useful for getting into smaller spaces like the small slot between opto-interrupters, as used on drop targets and flipper mechanisms. However, that phototransistor has not been tested for use in this article.<\/p>\n\n\n\n

    Resistor (10k\u03a9\/10kOhms \u2013 10,000 Ohms)<\/strong>
    1\/4 (0.25) Watt
    Axial Leads<\/p>\n\n\n

    \n
    \"A<\/a>
    A 10k Ohms resistor<\/figcaption><\/figure>\n<\/div>\n\n\n

    ATtiny85 Datasheet<\/strong><\/span><\/p>\n\n\n\n

    Atmel 8-bit AVR Microcontroller with 2\/4\/8K Bytes In-System Programmable Flash
    ATtiny25\/V \/ ATtiny45\/V \/ ATtiny85\/V
    Rev. 2586Q\u2013AVR\u201308\/2013
    The ATtiny85 datasheet can be found, in its entirety,     here<\/a>.<\/p>\n\n\n\n

    I\u2019ll save you from having to look through all 234 pages of the datasheet and show you a summary of the most important part we need to know about the ATtiny85 chip.<\/p>\n\n\n

    \n
    \"A<\/a>
    A small section of the ATtiny85 Datasheet<\/figcaption><\/figure>\n<\/div>\n\n\n

    The ATtiny85 can handle 40.0 mA of current per Input\/Output pin. This is plenty for our simple use.<\/p>\n\n\n\n

    Digispark Schematic<\/span><\/strong><\/p>\n\n\n

    \n
    \"The<\/a>
    The schematic for the Digispark design<\/figcaption><\/figure>\n<\/div>\n\n\n

    From the schematic above we can see that the Digispark (and most clone boards) have an onboard LED, as previously written about in this article. And, that a resistor (R5) is used to limit that LED\u2019s current.<\/p>\n\n\n\n

    More general information on LEDs<\/a> and more technical information, including limiting the operating current of LEDs, was covered in a previous Pinball News article<\/a>.<\/p>\n\n\n\n

    Taking an excerpt from the second, more technical article:<\/p>\n\n\n\n

    The following formula is based on Ohm\u2019s Law<\/a>.
    Rdrop = (Vin \u2013 Vled) \/ Iled<\/strong><\/em><\/td><\/tr><\/tbody><\/table><\/figure>\n\n\n\n

    When reviewing manufacturer\u2019s specification, you many need to substitute the following technical names in the formula below:<\/p>\n\n\n\n