Imagine your phone is ringing and you can't find it. Probably the last thing you want is for it to be quietly driving away from you. Well that's what this one does. The concept is simple: Take power directly from the battery and use the vibrator power as an input signal.
My biggest mistake was underspec'ing the transistor. â€œA motor can draw twice its specified current as it powers onâ€?. Once I had a more powerful transistor I tested it and the motor twitched once, then all was quiet. This was a good bit of encouragement. Everything did what it was supposed to do. It just didn't last very long before something died.
The successful transistor was a tip3055
These transistors are pretty common (uk). Having said that, I can't find it at DSE (nz), so these will also serve you well:
I've had lots of great feed back already, but if you see something that should be different, please let me know by commenting or email me at firstname.lastname@example.org. One suggestion was that I should explain more about the transistor, ie how it works and how to use it. This is too much for the purposes of this episode, but there will be another opportunity in an up and coming episode. In the mean time, take a look at:
There is also a massive amount of info at:
I haven't read all the way through all of these links, but I have been looking for particular material in there which is likely to help you, and these links should be most of what you need.