![pir sensor fritzing pir sensor fritzing](https://www.meccanismocomplesso.org/wp-content/uploads/2016/08/Meccanismo-complesso-Fritzing.jpg)
For the same reasons as before, we can’t do this “low side”, i.e.
Pir sensor fritzing series#
OK, how do you measure the amount of current a circuit draws? Easy: insert a small resistance in series with the load, and measure the voltage drop. If nothing has happened for a while, then we know there’s no important change pending. Most operating systems have a periodic flush in place, so that changes always get flushed out to disk fairly soon after they have been buffered by the OS. By adding a bit of extra logic in the sketch, we could implement a timer so that the disk will only be powered down if the disk has been idle for say 15 minutes. Here’s an idea: by adding a current sensor to each disk power supply line, we could monitor disk activity and make sure that power is never shut off while a disk is “doing something”. Some disks may stay off for weeks, even months. The whole point of these disks, is that I rarely need them. Nor tie it to a specific time of day, or day-of-the-week. I don’t want to have to remember to turn off the disks. Also, this isn’t really for disks which need to be online most of the time – for that, the normal hard disk spin down and idling modes will be fine.īut I’d like it to be a bit more automatic than that. It’ll take some scripting, depending on the OS, but it’s all doable. One solution would be to add a JeeLink to the computer, and have it send out the power down command only after it finishes flushing and unmounting the disk. So an unfortunate power down could leave the disk in an awful state: sure, the diks will be scanned and fixed on startup, but even then, some of the data blocks might contain inconsistent data. Even journaled disks are at risk, because journaling usually covers meta data (directories, files sizes, allocation maps, etc) … but not the data itself. You’re not supposed to power down disk drives just like that! It might be in the middle of a disk write. Ok, there’s now a design for a high-side power switch which can power disk drives up and down at will. Note that the boards will probably still be marked as “BMA020” on the silkscreen for a while – there’s little point in replacing them, given that the change is so totally compatible either way…
![pir sensor fritzing pir sensor fritzing](https://mechatrofice.com/wp-content/uploads/2020/10/pir-sensor-arduino-alarm-reset-1024x667.png)
It should have no impact on your projects if you use these accelerometers, but at least you’ll be able to “sort of” tell which is which from the temperature readout. Makes you wonder what the point is of having a chip “ID” register in the first place…Īnyway – in the near future, the Gravity Plug will be shipped with the new BMA150 chips. I have not found a way to distinguish these two chips at runtime – both report 0x02 in register 0 and 0x12 in register 1. Unfortunately, the old chip isn’t reporting anything consistent as temperature: GRAV 51 -31 -225 2 The reported temperature is in units of 0.5☌, so the above is reporting 20.5. Here is some sample output: GRAV 2 -10 130 41
![pir sensor fritzing pir sensor fritzing](https://www.tweaking4all.com/wp-content/uploads/2015/04/pir-test-simple-done.jpg)
Rf12_sendNow(0, &payload, sizeof payload) Memcpy(payload.axes, sensor.getAxes(), sizeof payload.axes)