Over the weekend, I was having fun with using an LED as a photodiode, and hooking it up to my oscilloscope. This can be used to measure the speed of a drill (just stick a reflective spot on a matte chuck and use a flashlight). I was going to make an Instructable on measuring rotational speeds of various objects, but my son told me that most people don't have an oscilloscope. But then I found you can just connect the LED to the microphone input on a phone and use a free oscilloscope app, and use that to measure rotational speed. And so I made an Instructable that doesn't need an oscilloscope.
Monday, June 30, 2014
Measuring rotational speed with a phone and an LED
Over the weekend, I was having fun with using an LED as a photodiode, and hooking it up to my oscilloscope. This can be used to measure the speed of a drill (just stick a reflective spot on a matte chuck and use a flashlight). I was going to make an Instructable on measuring rotational speeds of various objects, but my son told me that most people don't have an oscilloscope. But then I found you can just connect the LED to the microphone input on a phone and use a free oscilloscope app, and use that to measure rotational speed. And so I made an Instructable that doesn't need an oscilloscope.
Several years ago with no electronic experience I tried unsuccessfully to build this scanning tunneling microscope.
ReplyDeletehttp://www.geocities.com/spm_stm/
I think I will try again.
That looks really cool if you've got an XYZ analog oscilloscope (I have a digital two-channel one, but it doesn't even do XY).
ReplyDeleteThere are now more DIY STM projects online, and apparently a kit for about 800 euro.
Christmas will be here before you know it! Don't forget the signal generator.
ReplyDeleteMark: I made my own signal generator.
ReplyDeletehttp://www.instructables.com/id/Bluetooth-100kHz-two-channel-function-generator/
Very, very nice! I need to get back to work on my STM. That was kind of Tom Lauwers to recognize your contribution. He looks to be an interesting and good guy. I have been busy this spring and summer trying to grow giant pear gourds, pumpkins and tomatoes. The plants are like children and need attention. These things are interesting as you can watch the fruit grow daily. They get you out of the house and are excellent exercise.
ReplyDeleteYou might be able to use the Brainlink to control the STM, too.
ReplyDelete