So you’ve spent all weekend working on an awesome hack. It is demo time. You have exactly 2 mins to show it off to your hacking peers. You are at the podium, you look out at the faces in the crowd that are anticipating your demo. And nothing works. The 2 minutes stretch to two hours as you wait for that web page with your hack to load. You stammer a “what you would see if this was working” explanation and you leave the stage to a smattering of applause a much more humble person.

As one of the organizers for the Music Hack Day hackathon, I’ve sat through about 500 music hack demos in the last few years and I’ve probably seen at least 50 demo failures. Most of them could have been avoided with just a little bit of preparation. So here’s a list of the most common ways for demos to fail and how you can avoid them.

Hardware Failures

Hooking your computer up to a projector and audio projector should be easy, but sometimes it can be the most vexing of all. If you have the opportunity, do an A/V check before the demo session so you will have all the kinks worked out. Here are the most common failures:

• Missing Adapter – Don’t be surprised if you get to the podium to give your demo and the only thing there is a VGA connector. It never hurts to have an adapter that works with your computer/device in your pocket just in case. (but if you leave your adapter at the podium, you will never see it again).
  
• Projector won’t sync – it is the worst feeling in the world to connect your laptop to a projector and have it not see the projector. You should know how to force your computer to detect displays.
• No Internet – you are sitting in the audience hitting refresh on your demo web page ever 3 seconds. All is well. It is your turn to give your demo, you close your laptop, walk up to the podium, open it up, plug it in and find that your web page is no longer loading. I’ve see this happen dozens of times. It is easy to forget that when you close your laptop you may lose your network connection and may have to re-login to the local Internet provider before you get access. If you are running a non-web based demo that needs the Internet, this may be hard to notice. What’s worse, when there’s a big demo audience, with lots of laptops, iPads and iPhones, you may no longer even be able to reconnect to the local network. All the local IPs may be used up.
  
• Non-mirrored display – Lots of hackers have dual display setups. This can work against you when it is time to give a demo. What you see on your laptop in front of you is not what your audience can see. Moreover, the display topology probably won’t match the demo room layout so you may find you can’t even find a way to get your mouse onto the proper screen. Before you give a demo, make sure display mirroring is on.  Pro-tip – on a Mac hit CMD-F1 to toggle mirror mode.
• Unexpected display resolution – Projectors usually have a much lower resolution than your desktop. If you are running your demo in a browser, usually you can adjust to a lower resolution, but if your app is written to expect a fixed display size (such as common with a 3D library, or Processing), your app may just not work. Be especially careful if your app needs to switch into fullscreen mode.
• Colors don’t show properly – I’ve seen demos with beautiful visualizations fail because projectors couldn’t show the colors well. If you are relying on colors and textures in your app an A/V check is mandatory.
• No audio jack – At a Music Hack Day you can expect that there will be an audio jack that pipes your laptop audio to the P/A system, but this is not always the case for other hacking events. If you are at a non-music hacking event, double check to make sure that there is an adequate audio hookup. There’s nothing that sounds worse than a demo where you have to hold a microphone up to your laptop speakers so the audience can hear your music.
• Audio Problems –  (Added on 12/6/11) (This tip from Yuli Levtov).  For those doing hacks based on certain audio-based programming languages e.g. Pure Data, SuperCollider, MaxMSP etc., plugging and un-plugging the mini-jack in a laptop can make these applications behave strangely, as some OSs think the soundcard is being swapped.The solution to this is either a) use a USB soundcard and plug into the headphone jack output at the podium, or b) leave a headphone splitter (small, inexpensive piece of kit) plugged into the headphone output of your laptop at all times, and simply plug the podium minijack into the headphone splitter when you come to give your demo. This will prevent your OS thinking the soundcard has changed, and avoid any nasty needs to re-boot your whole music masterpiece.
• Too many things to hook up – No, you probably don’t need your power supply for a 2 minute demo. Probably don’t need your mouse either. Think twice about that turntable, those lasers, the full rack of keyboards and midi sequencers. Every extra item you bring to the podium doubles the chances of demo fail. Some of the best hacks ever were essentially slide show presentations
  

Podium Failures

Even if you have successfully hooked up your gear to the projector and audio you are not out of the woods yet. Giving a demo at a podium can be tricky

• Can’t type and hold a microphone at the same time – it is hard enough to type in front of a room full of people. The adrenalin is flowing and your hands are shaking. It is ten times worse if you are also trying to hold a microphone while typing. If there’s a podium or clip on microphone use it. Don’t try to type with a handheld microphone.
  
• That’s no podium, that’s a table – sometimes there’s no podium, your laptop will be on a desk. You can chose to give your demo standing up and do crouch typing, or sit at the desk where no one will be able to see you. Be ready for unusual setups.
• Notificatus Interruptus – Don’t forget to turn off growl, email and twitter clients that like to put up friendly messages in the middle of your demo.
  
• No place to put my mouse – If you really need to use a mouse, be ready to find that there’s no room at the podium for a mouse and a laptop.
• It’s chaos up there! – When timing is tight, you’ll find that you are trying to setup your demo while the previous demo is tearing down and while the MC is at the same time trying to get the on deck demo ready. Too many people, too many things to setup, too little time make for a very stressful couple of minutes. Don’t get flustered.
  

Presentation Failures

Once you have everything setup and connected properly it is time to give actually give your demo. There are still ways to snatch success from the jaws of failure:

• Practice – Giving a demo can be challenging. You are standing at a podium in front of a couple hundred people. Your showing off something that you’ve only just finished building. There may be bugs that you need to work around, the screen may be at the wrong resolution, your hands may be shaking. You may get flustered because the audio volume was too low. With all of this stuff going on, you will forget to demo that cool feature, or you will run out of time before you get to the showstopper. The key to a great demo is Practice Practice Practice. Know what you are going to demo, know what the results will be. Know what you are going to say. Time it, give yourself a few extra seconds of time. Run through it all 10 times.
  
• Tell us what your demo does – You’ve been living your demo all weekend, you know what it does, but the 200 people in the audience don’t. Tell us what it does. Tell us in a couple of different ways. Make it clear why it is new, cool and worth paying attention to.
  
• Budget the time properly – You have 2 minutes. We don’t need to know about the github issue you had. We don’t need to know about the difficulties you had installing numpy and scipy. Get to the meat of the demo.
• Don’t waste time telling us about what you failed to do – I’ve heard lots of demos where I was told about this nifty feature that they couldn’t get to work. Don’t demo your failures, demo you successes.
• Make your demo do one thing – Two minutes is not a long time. Especially when you are showing something complex. You may have 5 nifty features in your demo, but you will never be able to demo them all. Pick the coolest feature in your demo and plan to show it a couple of times in a couple of different ways.
  
• Demo it! – Don’t tell us what your demo is going to do. Show it to us.
  
• Be enthusiastic – Excitement is contagious. If you are excited about what you are showing, we will get excited too. If you are bored, we will be checking our twitter feed.