I think this has been done with a string and a bell already.
Of course you could use a rotating PIR, or maybe use IR emitters and detectors on the stakes to set a perimeter. Each stake has it's own power and noise source.
The starting point of any journey is "where do you want to go?". You need to have an idea of what you want to do before you can figure how to get there. Each type of project and industry has different requirements. It doesn't always take high level engineering knowledge to invent something. To...
Read it. There is nothing preventing you from transferring some of the charge from your recharged battery to the dead one. But you get nothing for nothing. First off no transformer is perfect so there will always be some loss, eddy currents, resistance in the windings...
The bottom line is you...
There was a small IC I saw years ago that would do exactly what you want. It's all in the chip. You do have to train it, but there is a secure and non-secure mode that uses the recognition threshold. It was something I was going to use to turn lights on and off as part of a home automation...
It's hard to determine from the information. There may be two answers. First some alarms use magnetic sensors at windows and doors. This is simply a magnet and a reed switch that is pulled closed by the magnet when they are close. The second type might be actually an inductive sensor. It is...
I could be wrong, but I think he is talking about the power LED on a device. Not power LED's as in high power. I also believe that the LED is being turned on now. He just wants to make this happen slowly rather than all at once.
Could be wrong and it wouldn't be the first time.
Hey eplanet...
I used to work for a company making current profilers. Sort of the same thing and they used piezo electric transducers.
You will need to transmit a pulse at the target. Don't really need to know the doppler shift since you are not trying to measure the speed exactly, just determine if they are...
Are you talking about the wind up clocks? Has a dial and arms for hours, minutes, seconds...?
How skilled at small stuff are you? :)
You can use the minute hand as a contact. Then drill a hole in the dial face and add another at the 12 position. This should be a wiper that can be pushed out of...
Omni,
You are very correct. There is no simple circuit for something like this. The cheapest approach is to use something already made and modify it to work. Properly constructed the environment isn't really a big problem. Most of this stuff would not be very sensitive and even with a uP design...
Take a look at the Maxim MAX878. It can do what you need. The circuit in the datasheet may be all you need. This part will regulate the voltage down, but if the input drops below the needed voltage it will switch over to BOOST mode automatically. Works down to 1V input too so you can really get...
Apologies to the board. I usually just attempt to answer the q's and not judge why people are asking them or call them names. I guess calling all Americans criminals or saying that all the criminals and guns in Canada are from America, a couple day's before Veterans Day (you civilians can call...