Wednesday, December 26, 2018

Enabling technologies for IoT development

Small scale / hobby IoT development has become much easier due to the following:
  • It is possible to buy electronic components in small numbers cheaply and reliably from China. It is a miracle of logistics that I get a couple of transistors for a couple of bucks, shipped to my doorstep from the other side of the world in two weeks!
  • Arduino, it's IDE and tons of libraries for all sorts of devices saves you from dealing with details of device drivers.
  • Machine learning with TensorflowOpenCV, and Raspberry Pi.
  • Cheap and reliable web services like AWS.
  • Easy to use server environments like NodeJS.
  • Last but not least, YouTube gets you up and running quickly.
We live in amazing times where everyone can tinker with electronics because the barriers to entry are so low now. Even my father who is 73 years old asked me the other day where he can get some breadboards! Imagine what the youngsters of today will come up with in the future.

Wednesday, December 05, 2018

Transistors

Differences between NPN & PNP Transistors: "...an NPN transistor turns on when the current flows through  the base of the transistor... A PNP transistor turns on when there is no current at the base of the transistor [i.e. the base is connected to the ground]." Usually, the middle pin (#2) is the base but there are transistors like the TIP120 whose base is pin 1, check the datasheet.

You can connect transistors in parallel to handle currents that a single transistor can't.