Adding sound, video and computers

The simplest and cheapest way to add sound and video to a slot machine or simulator used to be modified domestic CD and DVD players. I simply soldered wires to the contacts of the play and next track buttons to jump between tracks - and switch the power off at the end of each cycle to reset everything. Solid state 'media players' are now cheap and usually a better alternative.


Boom boxes (CD player, amp and speakers) cost about £20. There is a delay of about 6 seconds between power on and it playing, but it is possible to record the first track blank so the machine just has to skip to the next track when a coin is inserted. You obviously need some sound software on your computer, and a CD burner to master your CD.

Another possibility is to run MP3 files on an V2 music module, sold by FTDI, with an Arduino controller. I used this on Whack a Banker and it works really well (about £15 for the Arduino and £22 for the V2music module) but it needs a bit more programming and electronics skill. (Maplin now sell an MP3 shield for Arduinos. 

For amplifying the MP3 sound, 'active' computer speakers are good value. These plug into the phono audio out sockets of a DVD or media player. A bass speaker and amp with two satellite speakers cost about £30. It doesnít matter where the bass speaker is but the tweeters need to as close to the ears of the people using the machine as possible. This enables the sound to be easily audible without being played at high volume Ė which pollutes the rest of the space (conventional amusement arcades never seem to have applied this simple lesson).


Video keeps getting cheaper and easier to incorporate. At first, I ran the video animation for my simulator rides from set top DVD players. Starting the DVD playing at the same time as the main controller, they keep perfectly in sync as their internal timing circuits are both quartz controlled.

Solid state video players, running from compact flash card memory are more reliable. I run most of them with a player called a Brightsign HD 120, about £200 + £14 for a switch keyboard for accessing 8 different tracks). As the name suggests, it will also play HD movies.

HD TV is good for arcade machines because people are watching the screen close up. However the video compression often degrades the image between the camera and the final edited film so try everything because the finished result is often not much better than ordinary 640x480. 

I often need to convert between HDMI and VGA and composite video to connect camera and monitors and players. I used to have enormous trouble with this - particularly cheap converters on Ebay. But I've found that HD videos made at 720p work much more readily than ones made at 1080p.

Video Monitors

It is not completely straightforward to get an ordinary TV set to switch on and find the right channel automatically.  Most TVs switch on to standby mode, so I add a delayed pulse timer (RS 365-6993), giving it an initial pulse contact to the channel+ button. Most TVs switch on the channel that was on when the set was last switched off. 
I have tried open frame industrial monitors, which are much more convenient because they have glass screens and switch on automatically when the power comes on. The downside is that they are much more expensive and in my experience not as bright as ordinary TVs. Most of my videos are 4x3 format, so old LCD TVs from ebay are great, and new 17 inch 5x4 screen ratio monitors also work well. 


Iíve tried incorporating a PC in two coin op machines. In one (the Gene Forecaster), I wired into the mouse button. This simply started a macromedia director movie. The start menu can also be set to launch any program automatically.

In the other machine  (my Expressive Photobooth) other I wired external switches to 5 of the keyboard switches. Macros, called actions in photoshop, are then triggered by the keyboard switches. This is a powerful technique which has all sorts of possibilities for making elaborate machines without any programming language skills.

 The disadvantages of using home computers is that when something does go wrong, there are so many levels of complexity that itís very time consuming and expensive tracing faults. Perhaps I should be less pessimistic as the major faults I spent years tracking down weren't buried too deeply.  One was simply caused by inadequate cooling Ė the computer was inside the machine housing. The others were caused by inadequate shielding round the keyboard interface circuit and a buggy Logicec webcam driver. However the enormous amount of time it took to pin down these faults really put me off. I recently rebuilt the Gene forecaster with a video player instead of a computer, and its worked perfectly ever since.