During time I’ve been purchasing or building various microcontroller boards. Most of them were used just to try things out or because they were cheap to get. So I thought, why not to blow dust away and see what we have here. Maybe there will be some fresh thoughts on where to use them.
Probably I should spare a few words about each of them. (more…)
Recently I obtained a Samsung Galaxy Ace S5830 android mobile phone. It was released a year before but it seems to have enough power to run most of apps you can find around.
It is powered by Qualcomm MSM7227 ARM11 processor running at 832MHz. Has internal 158MB of internal memory and can support up to 32GB MicroSD flash card. Other features include GPS, WiFi, 320×480 TFT touch screen, 5MP camera and so on. Device is powered by Android OS v2.3. These are specs you can find on any mobile website. To get your own Samsung phone, check out phones4u.
Smart phone devices are as valuable as there are some useful apps there. So I started wandering if there are electronics/microcontroller related apps that could be useful in daily work. Lets see what can we find in app store. First of all we are interested in free apps. Search on AVR microcontrollers gave me coupe results: AVR Fuse Calculator and Using Atmega128 apps. Lets see what are they capable of. (more…)
Some time ago we noticed that Cornel University ECE4760 project list started to build up. It seems that the project list is finished with 30 great projects built around AVR microcontrollers. Students as always prove to be creative and inspiring. Like each year they came up with new ideas and implementations. We like that they use free tools to build them. The compiler they use is WinAVR/GCC compiler. So everyone can replicate one or another idea if needed.
It is hard to go through whole project list as it would tike time and we still wouldn’t be able to tell the thing. Some of them really are worth attention like EEG Pong, where device reads brain waves and this controls computer cursor. (more…)
Modern cars have more electronics than you can think of. Almost every important part has tons of sensors on it that has a dedicated computer called ECU (Electrical Control Unit). Usually there are from several up to hundreds of ECU’s on a single car. Especially luxury ones. All modules has to work as on organized unit. So this is where reliable connection interface needed.
Probably you’ve already heard of CAN bus (Controller Area Network). It is common bus interface used in most vehicles where board computer communicates with separate control ECUs taking care of engine, gearbox, climate, security alarm, safety bags. Talking of physical interfacing CAN devices are connected by using twisted pair signal wires that are resistant to noises. Signals usually operate at 5V level. Transmit/receive can be 1Mb/s for 40m cable lengths. Engineers have put lots of thought in to CAN protocol. It was designed to be flexible reliable and robust. There can be more than one master CAN device on same buss. So there can be situation when several masters would start communication. In this case there is a message priority used to determine which one will have right to transmit data. CAN nodes act as independent units and can receive any message and take act if needed. This feature is called ‘multicast’. This allows adding new CAN devices to existing bus without need to reconfigure existing setup.
CAN interface is quite complex interface allowing to have multiple masters what makes it robust and versatile. But due to growing cost of amount of electronics used in cars, manufacturers started looking for cheaper solutions that would complement the CAN bus and be cheaper. So they came up with LIN (Local Interconnect Network) bus. LIN bus interface is simpler standard comparing to CAN. LIN can have up to 16 slave nodes controlled by one master. It is slower and cheaper as nodes are clocked by master (no crystals for each node). LIN can be simply implemented as sub-function in CAN LIN interface USART RISC microcontroller. While CAN transceiver is complex device so it usually comes as separate peripheral or as separate chip. LIN uses single wire for communications with about 40V signal voltage level. It can reach up to19.2kbps communication speed with maximum 40m length of line.
After this short overview it is obvious that LIN interface is low band, less effective bus interface comparing to CAN. In other hand where efficiency isn’t as ‘must’ factor it serves as cheap complement to CAN network.