Node code for PCB 1.4.

I have just created new repositories for nodes version 1.4. Although you can, similarly as I did, covert the code from version 1.3. But all new changes will be as always targeted to the latest version.

https://github.com/vysocan/remote_1_4_Key_Temp.git

https://github.com/vysocan/remote_1_4_RFM69.git

There are some changes mostly needed for new hardware features present, like charging indicator and other small corrections.

Auto arm moved from zone to group

After improving auto arm, I have realized that auto arm flag should be moved into group instead of zone. That is, it make no sense to have just one zone flagged as auto arm in a group. The algorithm then would not work, if user will not flag all zones in auto arm group, it will not consider all zones.  And most probably gateway will auto arm group that still has some movement detected. To prevent this possible human error, I have moved the auto arm flag to Group setting.

Changes are pushed into GitHub.

The use of auto arm feature can be greatly extended. For example, it can be easily used to lock an electromagnetic locks when authentication node will receive arm packet. As easy as wiring a pair of cable to node, but of course you have to have the electromagnetic locks installed first :).

Improved auto arm

I have just committed to github new improved part for auto arm feature. Previous code mapped the auto arm to zone with oldest alarm, and that was impractical when there was more then one zone in a group. Now the gateway selects it by taking newest alarm from any zone that is in the group. That is, if there is someone moving in at least one zone in a group, the group will not get auto armed.

I will not yet release it as new version, as I have in mind some other improvements.

SIM800 vs. SIM900

Well it actually looks like there are some differences in SIM800 comparing to SIM900. Echo and command routines are working just fine, but reply to SMS send function is different. SMS is actually sent, but the function is not able detect successful sent. There seems to be two reasons. First, the reply looks little different. That is the echo of SMS text is not preceded with empty line and "> ", but there is simply one line with echo. Second, the reply time of SIM800 is significantly slower then SIM900. It looks like "CMGS:#", the acknowledgement of SMS, comes after the SMS is delivered to actual number.

First problem is relatively easy to solve, on beginning we can ask GSM modem for the version and then branch the SMS send function depending on model. But the second must be investigated. I've seen some command that can make difference in how the SMS sending is handled, but the setting in SIM800 looks right already, interesting :).

Blue gateway 1.7C

A picture is worth a thousand words. Here is new OHS gateway officially named 1.7C. Major difference comparing to 1.7. is 2G modem SIM800C. With four bands GSM support it can be deployed worldwide. And just one remark to relays, I have switched from black Chinese made Omron to blue one's made in Japan. They are slightly more expensive, but somehow cute and blue :).

Nodes

New nodes now come with blue PCB and as option with USB charger. Here on picture you can see battery powered node with USB charging circuit and temperature sensor. On back there is RFM69HW module, also available as option, and 720mAh Li-on battery. Such batteries can be found on ebay. They are sold for quadrocopter toys, and even they are labeled as 25C RC, they have build in protection circuit.


Further more I will, or I can, equip all battery powered nodes with 8MHz crystal oscillator instead of 16MHz. This reduce the power consumption even more. The whole setup on picture has following consumption:

ATmega328P@8MHz sleeping 33.2~33.6uA
ATmega328P@8MHz running ~4mA

Just to ones that are curious what are the missing components. This board can be either battery or DC powered, and also can communicate over radio(RFM69HW) or RS485.

Blue gateways

The life of components in electronics can also come to an end. So is true about SIM900 GSM modem that is part of GW version 1.7. Although it is still available online, officially it is not recommended for new development, and local distributors have no longer any in stock. The decision had come to choose new GSM module. As SIMCom modules have proven to be reliable at good price, I had in mind to switch over to some of their new model. Put it simple SIM800C was chosen to be a replacement. It is still 2G modem with four band GSM support and can be deployed worldwide. Fortunately there is no difference in AT command set that is used by gateway firmware, so the new boards are interchangeable in terms of code. There seems to be interest in 3G modem of OHS gateway users that are located in U.S.A., but for now we stay at 2G (3G module is 4x expensive then 2G, and 3G band are varying across regions. But if there will be interest, I will design new version of gateway with possibility to mount 3G or 2G module).

New boards have also same footprint and connectors location have not changed, except for SIM card holder and GSM antenna connector. They are named 1.7C and come in blue colour with round edges similar to new nodes.

P.S. Picture will come soon :)