Is there anyone who didn’t hear about Raspberry Pi? It’s like second thing after Arduino. And this is the result of right idea at the right time. There’s been mane Linux boards around that don’t cost a fortune but they didn’t make to masses. And mostly they were used by advanced users who knows Linux well enough.
Raspberry Pi changed things pretty drastically. And there are several key factors why:
Minimum user effort to get it working. Admit it – Raspberry Pi team made great job in preparing things to work Linux almost out of box. Just write pre-compiled image to flash and you are done.
Plug and play capability. You don’t need to mack around in order to get visual output or input. All you need is to plug monitor to HDMI port or use any TV with Video input and you are graded with video image. And it supports 1080p video.
Intrigue from first moment. Remember how Raspberry Pi was introduced first? The buzz was created way before the actual board appeared. This made people anxious to get and try. And it still feels that spirit of “Hard To Find Raspberry Pi” flows around. Probably it is from several retailers, but eBay never ran out of them.
Price. Obviously it is cheap. A 700MHz + 512MB computer for like $35 is a real bargain. Even original Arduino cost more. People by them even if there is no real purpose.
GPIO. This is last but not least important feature. Raspberry Pi has pins specially for interfacing various I/O devices. You can use this header for attaching custom made boards, devices and other electronics you want to control.
What about Raspberry Pi cons? There are several things that can cause problems. One thing is hardware drivers. It takes time to get polished, so no wander if it may fail sometimes. This mostly applies to Ethernet or USB drivers. Another issue is power supply. Since Raspberry Pi is USB powered (micro USB) it can give up to 700mA, While each USB port can supply no more than 140mA. If you need to connect power hungry USB peripherals like external hard drives, the only way is to use USB hub with separate power supply. It’s OK to connect things like keyboard, Mouse or Flash drive. Same thing applies to GPIO. Pins are connected directly to CPU (Broadcom chip), so you must be careful not to short or damage port with high voltages. Each pin can drive up to 16mA of current. There is no analog input or hardware PWM. Additional features can be implemented with expansion boards.
Even if there are few options to get visual view of Linux (HDMI, RCA, SSH, VNC or serial), there is also a DSI interface included. As far as I looked, there are still no available displays to get with this interface and whole DSI specs thing is somewhat not widely accessible. If connector is already there, this would be great to be usable. Hopefully in future we will see some solutions. Same applies to CSI – camera interface. There is some results with DSI camera prototype, but still no news about release of expansion.
Even if it is a fully functioning computer, it is not recommended to use as desktop computer. It may be not very stable sometimes. It is relatively slow – 700MHz isn’t rocket speed even if it can be overclocked. 512Mb ram is also limiting factor and cannot be expanded. In other hand raspberry Pi is a great learning tool. If you never touched Linux, Raspberry Pi can make this fairly easy to get used to. There are tons of tutorials, hundreds of websites, rapid growing number of projects.
No doubt Raspberry Pi is a game changer and is definitely worth trying.