Thursday, May 14, 2015

An Inexpensive Gym Scoreboard

After looking into scoreboards for our church's gym we decided that a traditional full-size scoreboard was not within our budget.  We decided to look into using a computer/tablet/phone along with a large screen TV to act as a scoreboard.  We ended up using an Android tablet and an overhead projector along with Chromecast screen casting technology to create an inexpensive scoreboard.  I describe the system we put together in some detail in this post. Everyone seems to really like the system and, best of all, the total cost was only around $120. (That price includes a tablet! It does not include the overhead projector - we already had one.)  You can see the scoreboards on the opposite of the gym floor in the image above.  (The scoreboards are washed out in the image.  They look better in real-life!)

Before going into the details, here are some of the options we considered:
  1. Display - We considered mounting a large screen TV on the gym wall to use as a display. The TVs are not that expensive, but we needed to enclose the TV inside a cage/barrier to protect it from being broken when it was hit by basketballs, volleyballs, etc. The commercial protection cages were more expensive than the TV.  I noticed a local high school gym protects their scoreboard with a weighted mesh that is positioned about three feet in front of the scoreboard. That would be an inexpensive option. Our gym has a recessed stage beside the long dimension of the court. The stage has two rear-screen projectors and two motor operated screens. We decided to use these for the scoreboard display.  The location of the projectors protects them from being hit by stray balls. There is some concern that an errant ball might damage one of the screens, but we have been lucky so far. We can mount a weighted mesh in front the screens to protect them if we decide that needs to be done. The projectors don't provide as sharp a display as a TV might under full light, but it is satisfactory.
  2. Wired/wireless - A wired connection from the computer to the display is relatively inexpensive (although depending on your computer and display you may need a video adaptor), but we wanted the convenience of wireless. (Being able to keep score from anywhere within the gym has proven to be a very nice feature of the system.) The church already has WIFI, but the signal is pretty weak inside the gym. I bought a "HooToo TripMate Nano Wireless N Pocket Travel Router" (under $20) to set up a private "scoreboard" WIFI network within the gym. This works well and provides a consistent connection throughout the gym. (I don't know the specified range of the HooToo.) I believe that there are performance and security advantages to a private scoreboard network also.
  3. Computer - We did not believe we had the budget to allow the purchase of a dedicated computer/pad, so we originally set the system up so that anyone with a smart phone could "cast" their screen to the display. In order for this to work users have to download screencasting and scoreboard apps and then learn how to connect to the scoreboard WIFI network and the screencast device. After training a couple of users, we used the system like this for a couple of weeks. I then found an inexpensive tablet ("Proscan 7 Android 4.4 KitKat Touchscreen Tablet" for under $40) that was within our budget. This has worked much better than I had expected.  We just leave the tablet at the church with the other scoreboard hardware. All of the necessary software is installed and the tablet automatically connects to the WIFI network. Training people on how to use the scoreboard takes only a few minutes (assuming that they have prior experience with smart phones or tablets).
  4. Screencast/Mirroring Technology - There does not appear to be a standard in screencast/mirroring technology.  MiraCast technology appears to be closest to being a standard, but is poorly supported. Apple devices have better support for screencasting via AirPlay and Android devices have better support for screencasting via Chromecast. For example, my Moto G phone can screen cast to Chromecast, but can't screencast to MiraCast (or AirPlay). The Android tablet we purchased can't screencast via MiraCast either (but can screencast to Chromecast). Since I was setting the system up and wanted to be able to use my phone, I decided to go with Chromecast. I had originally only planned to use Chromecast and Android devices, but was asked to provide support for Apple devices too. I found the "Tronsmart T1000" HDMI dongle (under $30) that provides screencast (via AirPlay) support for Apple devices. We tested it and it worked.  This device is also supposed to support Android screen casting via MiraCast, but since my phone doesn't support MiraCast I was never able to test it. Since buying the Android tablet, everyone uses that now (and screencasting via Chromecast) instead of their own phones and the AirPlay has never been used beyond testing. Both the Chromecast and Tronsmart devices are HDMI dongles.  I bought an HDMI switch (the "PORTTA PET0301S" for under $7) to make it easy to switch between the two dongles. This isn't necessary any longer since we only use the Chromecast (under $30) now.

Here is a block diagram of all of the hardware (the Tronsmart and HDMI switch are not shown since they are no longer used):

Our projectors have VGA connectors.  I had to purchase an HDMI to VGA converter (enKo HDMI To VGA + Audio Converter for under $30) in order to connect the Chromecast to the projector.  I believe most newer projectors have DVI connectors.  HDMI to DVI adapters are much cheaper ($5). Since we were using two projectors and two screens a VGA Splitter was required (since the cable runs to the projectors are long we actually needed a Splitter/Driver).  The church already had one, so I did not need to purchase one.  A new one costs around $10.

Here was the cost breakdown for our scoreboard:
  • $30 - Chromecast
  • $20 - HooToo Router
  • $30 - HDMI to VGA Converter
  • $40 - Android Tablet
for a total of $120.  I purchased everything on Amazon except for the tablet which came from hhgregg.  We already had the VGA Splitter and the projectors and screens.  If you need to purchase a projector and screen or a large screen TV your cost will be several hundred dollars more, but probably still $1000s less than a commercial full-size scoreboard. (Portable table-top scoreboards are around $500.) You may not need the WIFI Router (if you have existing WIFI) or the HDMI to VGA Converter or VGA Splitter (depending on the available connections on your display device).  I did not do a lot of searching for lowest price, so you may be able to do better.

Scoreboard Notes:
  • Android Scoreboard Apps - The apps we use are available from the Google Play store. We use the Volleyball Score app from Redblue Labs as our volleyball scoreboard app.  This is a free app. We use the Scoreboard +++ app from Alecs+++ as our basketball app.  This app is only $1.99. The Scoreboard +++ app is actually a multi-sport app that supports volleyball in addition to basketball, but we prefer the Volleyball Score app for volleyball.  (There are similar apps in the Apple Play Store.)

Volleyball Score

Scoreboard +++ (Basketball Mode)
  • Sound - We don't use sound with our scoreboard even though some of the apps provide it (horns, buzzers, whistles).  The HDMI to VGA Converter has an output audio connector to which you can hook (powered) speakers if you want sound.
  • Android Screencast - Older Android devices do not support screen casting (mirroring) via Chromecast. My Moto G phone supports it, as does the Proscan tablet we bought for use with the scoreboard. Don't expect older Android devices to work. I believe newer Android devices running Android 4.4.2 or higher are supposed to work, but I certainly can't provide any guarantees. (At first it appeared as if the Proscan did not support screencasting via Chromecast.  It worked fine after updating to the latest version of Google Play Services though.)
  • Other Uses - The projection system can also be used to show movies or videos via apps that support Chromecast (Google Play, Netflix, Youtube, etc).  You will then want to make sure that you have working Sound.
  • Configuration - Setting up a private WIFI network using the HooToo router is probably the most complicated part of the initial system configuration. It is not too complicated for someone who has some basic networking knowledge. Our HooToo also connects to the church's WIFI to provide an Internet connection for the Chromecast (see the Chromecast notes below). If you use an existing WIFI network setup should be relatively simple. Setting up the Chromecast requires some basic networking knowledge also.
  • Network - Although using an existing WIFI network may be easy to setup, using a new private scoreboard WIFI network will not increase the traffic on an existing network.  The private network may provide throughput (the only two devices on the network are the Chromecast and the Android pad) and security advantages.
  • Setup - All of the hardware is kept in a small plastic bin that is locked in a closet. The HDMI to VGA Converter is attached with velcro to the top of the VGA Splitter. All hardware is plugged into a 6-plug AC adapter. We take the hardware out of the bin, plug the AC adapter into a wall outlet, and plug the projector cables into the VGA splitter. The HooToo router is plugged into a different AC outlet that is closer to the Android pad. Everything comes up automatically although it can take as long as 5 minutes for the Chromecast to become ready. We then just start the Chromecast app on the Android pad and choose "Cast Screen" from the menu.  Start the desired scoreboard app and we are up and running.
  • Chromecast - The Chromecast needs to be able to connect to the Internet when it first powers up otherwise it can't be used for local casting.  This is an unfortunate drawback to using the Chromecast for screencasting.  Our HooToo router is setup to connect to the church's WIFI to provide this Internet connection.  If there is no Internet connection available, you can setup a phone as a WIFI hotspot and use your phone to provide the connection to the Internet.  After the Chromecast becomes ready (the LED on the Chromecast turns white) the Internet connection is no longer needed.  (I hope that a future Chromecast update allows the Chromecast to be used for screencasting without requiring an Internet connection.  Come on Google!)  If this is an issue for you, I don't believe the Apple AirPlay or MiraCast devices have this restriction.
  • Tablet - I am very pleased with how well this $40 Android tablet has performed.  We have been using it for over 6 months and it is still going strong.  At this price I am not too worried about the device being stolen or lost. We normally lock it away in a closet, but it has been accidentally left out on more than one occasion. At the same time a more expensive tablet may provide more features. Our tablet does not appear to be very rugged, but so far everyone has been careful with it and it hasn't been dropped (at least to my knowledge).  Processing performance has not been an issue at all.  The wireless Ethernet adapter in the tablet seems to have a short range.  This was initially a problem when we placed the HooToo router next to the Chromecast and about 10-15 meters away from the tablet.  The WIFI connection between the tablet and router would occasionally be lost.  After moving the router closer to the tablet this has not been a problem.  (Through trial-and-error we seem to have found a "sweet spot" for the router location.  We now appear to have a good connection between the router and the tablet as long as the tablet is within the gym (as much as 30 meters away).)  Our volleyball league runs from 6-10PM. If the tablet is fully charged it can (almost?) make it through the entire 4 hour period.  Our scorekeeper is normally seated near an AC power outlet and so we can easily plug the tablet in when the battery runs low.


  1. You can use this app for competitions with three or more teams/players

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