aj’s blog

I recently upgraded my lawnmower robot from a Robomow City 110 to a Gardena Sileno City 250. Main reason for the changeover (besides dying batteries) was the mowing noise; the Robomow was quite noisy, both in terms of driving and mowing noise. Also as my lawn is not completely flat and the Robomow’s hard plastic chassis is not fixed but able to move around for “hard” obstacle detection purposes that always generated some sort of rattling noise.

The Gardena is much quieter although the more expensive Gardena lawnmower robot models seem to be even more quiet. With my model there is almost no driving or blade rotation noise, however there is a bit of noise that can be best described as “blades hit grass”. Depending on the height of the grass this can be unexpectedly loud however it’s supposed to become better the more the robot runs – mainly because it has less to cut.

There are different models of the Sileno City; I chose the most basic one because I don’t really need any of the “Smart” cloud features the higher-priced models have and because it only has to take care of about 160m². Getting a “Smart” model would have meant to choose the next bigger model, the “Sileno City 500” (+200 EUR) which is available “Smart” enabled as “Smart Sileno City 500” (plus another 100 EUR); basically they just don’t seem to sell the City 250 smart-enabled. And you’d have to trust “the cloud”.

According to some threads in the German Robotics forum it might be possible to get the “Smart” capabilities as an upgrade for the 250 by sending it to Gardena and having it upgraded which seems to consist of adding an additional internal board for wireless communications (863 – 870 MHz).

Reading these forums I came across a note that the Sileno City models are Bluetooth enabled for future software upgrades, which is also listed in the model specifications in the owner’s manual. Doing some research about these Bluetooth capabilities I noticed that Husqvarna offers a free App called “Automower Connect” for some of their “Automower” series lawnmower robots. Since Gardena is a part of Husqvarna group and advertises “20 years of experience” with lawnmower robots it’s pretty clear that these are all basically building up on known Husqvarna technology. If you know Husqvarna Automower robots – you will immediately see the similarities when looking at these Gardena devices.

The current version of “Automower Connect” (“AMC”) in the Android Playstore as of writing of this post is version 3.1.7 dated January 23^rd, 2019. Turns out this App can’t just connect to Cloud-enabled Automowers but also offers an “Automower Direct” mode. This mode seems to have been introduced as an Automower product feature called “Automower Connect@Home” in 2018 and allows you to control your lawnmower robot via Bluetooth LE (BTLE).

Well… long story short – the non-smart Gardena Sileno City 250 is still smart enough to be found by this App. However similar to Automowers the initial pairing needs to happen within about 3 minutes after the robot has been powered on, so if you experience issues pairing make sure to fully turn it off (power LED not on or flashing), then turn it back on and try to pair.

Almost all App features for controlling the robot seem to work: Start, Pause, Resume, Park, Override Schedule (for x hours); including remotely editing the mowing schedule which is quite nice given the limited interface available on the robot itself.

What doesn’t work in the App are the mower settings; seems the Gardena robots either have a more limited or slightly different command set. However, it’s still very nice that the non-smart robot is smart enough to be controlled via Bluetooth LE. 30 meters line-of-sight were not an issue at all and I was quite surprised that the connection still worked through some concrete walls. Of course this can’t be compared to the featureset of the Gardena Smart module but seems to be sufficient for controlling the robot from a few meters away without having to walk to it, stopping it and pressing some buttons.

Based on the discussions in the German Robotics forum this also works with the same App on IOS and with other mower models such as Gardena Sileno City 500 and Gardena Sileno Life 750. There also seems to be an App for the Apple smart watch allowing you to control your lawnmower robot from your clock – of course only as long as the associated mobile phone is within Bluetooth distance of the lawnmower robot.

However there seem to be some limitations in terms of firmware versions; it does not seem to work with firmware 11.04 or earlier but was tested ok with firmware 11.07 and 14.04.

I will probably post a follow-up soon with some more details about the BT LE communication used between App and robot.

Hope that someone will find this useful; if you have anything to add or want to provide feedback please use the comments area below. Enjoy!

While Windows 7 seems to run quite okay as a QEMU-KVM guest on my home server – which I will cover in another posting – there are a few things that I’ve noticed and that should be kept in mind when playing around with such setup.

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Recently during investigating some strange network packets sourced from my new D-Link switch when configured for “loopback detection” I came across “RRCP”, or “Realtek Remote Control Protocol” (ethertype 0x8899). I had never heard of it before, even though it seems to be quite interesting.

Basically it’s a protocol for configuring a network switch without the need of an embedded microcontroller usually used for displaying fancy web GUIs or telnet prompts. It works with Realtek chips RTL8316BP, RTL8318P, RTL8324P, RTL8316B, RTL8324, RTL8326 and RTL8326S that are often found in switches, even in cheap unmanaged ones. Depending on the specific type of switch this basically means – RRCP can sometimes be used to more or less turn a cheap unmanaged switch into a managed one, in some cases even without any hardware changes or with only minor changes such as soldering off a small SMD resistor.

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In order to improve my home network by increasing transfer speeds and adding new features I recently started to compare a bunch of small managed gigabit switches. My main criteria were that the device should have at least 10 ports, fanless operation, small device size, good feature-set, low power usage, long warranty and all that for a competitive price.

I quickly came across the D-Link DGS-1100-16, a 16 port switch that matched my expectations as mentioned above, and sells for about 120€ around here. Other vendors in this segment seem to prefer to sell huge 19″ devices even though the extra space within the device isn’t needed at all (Hello TP-Link?) or try to sell “managed” switches that are only “manageable” using some special Windows GUI software (Yes, NetGear, I’m looking at you).

See below for a short review of the D-Link DGS-1100-16 “16-Port Layer2 EasySmart Gigabit Switch”. (more…)

I recently noticed a rather high “load cycle count” SMART value (“smartctl –all“) for my new harddrives that are only in operation for a few hours. Sure thing, I also heard the clicking noise of load-/unloading disk heads every now and then.

193 Load_Cycle_Count        0x0032   100   100   000    Old_age   Always       -       395

As the number of load cycles is somewhat limited – a rather high value, but limited nevertheless – over the lifetime of the disk I decided to disable the disk power management feature that caused these load cycles.

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