approaching RC1

parent 53f118b8
......@@ -27,9 +27,16 @@ FHEM can also be found in this repository.
### Intro
This has been designed for low power applications, and when not transmitting
This has been designed for low power usage, and when not transmitting the circuitry
uses only a fraction of a miliampere (around 0.06 mA at 2 volts input voltage,
this depends on the input voltage obviously).
this depends on the input voltage obviously). This should guarantee a long
battery life, but it's still unknown how long this will be, it hasn't been
tested yet. However, at the time of writing this, I have been running one of
these devices for over a month, with batteries that came used out of another
(commercial) radio temperature sensor, because they were too empty for that
one to continue to work. So far, there has been no measurable voltage drop
on those used batteries (2x AA), they're still at the 2.2V they started
with.
### BOM
......@@ -61,7 +68,7 @@ together. The bill of materials therefore is short:
* small capacitor. Everything >= 1 nF should be just fine, I used 100 nF
because I had that lying around.
* Goobay 78467 battery tray. This is simply a battery holder for two
AA batteries that has cables attached.
AA / mignon batteries that has cables attached.
* an additional 100 uF capacitor for stabilizing power, simply soldered
between the power pin and ground. This is completely
optional. I added it because IMHO the capacitors on the JeeNode Micro
......@@ -183,9 +190,21 @@ firmware as the format for custom sensors, it looks as follows:
| 5 | Temperature LSB (raw value from SHT31) |
| 6 | Humidity MSB (raw value from SHT31) |
| 7 | Humidity LSB (raw value from SHT31) |
| 8 | Battery voltage (with the 10:1 voltage divider, this is on a scale from 0 = 0V to 0xff = 3.3V |
| 8 | Battery voltage (with the 10:1 voltage divider, this is on a scale from 0 = 0V to 0xff = 3.3V) |
| 9 | Checksum |
The firmware is not in any way dependant on Arduino libraries
or tools, you just need avrlibc and avr-gcc.
Flashing the firmware onto the JNu is a bit tricky: it doesn't
have a bootloader (or a serial port you could talk to). You
will have to use an ISP programmer that supports a voltage of
3.0 volts, because that is what the microcontroller on the JNu
runs at. Due to space constraints, there also isn't a standard
6 pin ISP connector on it, just the 4 data pins are brought
out and you'll have to use power and ground pins elsewhere.
There is [some information about this upstream](http://jeelabs.org/2013/03/03/programming-the-jnu-v3-part-1/).
## Software
The FHEM module can be found in the file `36_Foxtemp2016viaJeelink.pm`.
......
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