Last month our 2010 27″ iMac stopped working. There was no drama, just a black screen where previously had been the High Sierra backdrop. A quick bit of investigation showed that it wasn’t as simple as a dead machine. The fans still blew and when turned off and on it made all the expected noises. There was just no picture. Plugging in an external monitor soon showed that the machine was usable and still functioning normally. After 7 years...
For years all I heard from various people I know was “ZFS“. It was the answer to almost every question and given how few OS’s supported it always appeared to be the promised land over the rainbow. That was then, but in recent years the availability of ZFS has grown quickly and I can now fully appreciate what they were saying was true. I’ve used ZFS on Ubuntu and now am using it on FreeBSD without too many...
Over the last few days I’ve been trying to help one of my users who had an odd connectivity issue for my server. After looking at the obvious issues it started to look more and more like he had triggered one of the fail2ban rules and was being blocked by iptables. This has been the case a few times and normally checking the rules shows the problem, but this time it didn’t show anything obvious. $ sudo iptables -L...
I’ve been using Postfix for around 5 years now and it’s been a great solution for mail. Initially I used a single instance, but as the mail volume grew it started to cause bottlenecks and frustrations. The solution was to move from one instance to 3! Basic Flow The theory is to have each instance of postfix performing a specific role and using the standard communication mechanism between them. Each instance operates independently and using it’s own...
I’ve recently started moving back to FreeBSD from Ubuntu. As it’s a large move and I’ve not touched FreeBSD for quite a few years, baby steps are required. With that in mind I’ve started small with my home server and once I’m comfortable with that and how things work I’ll look at moving my online server. The reasons for the move will have to wait for another post 🙂 Previous the home server had both...
The KroozSD board now comes with a handy SWD connector, a simple 3 pin 1mm JST located in the middle of the board. As debugging is one of the harder aspects of embedded development the connector has always been an interesting addition but finding a way to interact with the port has proved tricky. While I have several devices that claim to offer the required interfaces, none of them have proved to be supported. However, I came across an article...
In my earlier post I said that the bootloader for the KroozSD was luftboot, but in reality it’s available here. The version contained in that tree doesn’t appear to be fully up to date as there is no CRC and the strings reported by the device are different, but I’m assuming the current code is similar. While I realise I could simply switch to a different laptop, I can’t help but feel this should be a...
6! Who knew I’d get this far and still not have a flying quad? At least I’m getting closer and learning a lot along the way… Satellite Receiver I’ve updated the spektrum_serial.py code to have code that now converts the split channels into appropriate values and having watched it what it produces seems sane. Using this is a basis I changed the code in paparazzi to do the same conversions and rebuilt. All was well...
Having spent some more time looking at the Spektrum SPM9246 satellite receiver and it’s output I’ve made some progress. When trying to use this with Paparazzi I’ve had very variable results and it fails to work. Direct Binding Doesn’t Work 🙁 I’ve been unable to get the binding via the KroozSD board to work with the satellite and watching the output using pigpiod (as detailed Quad Update #4) the reason became clear as the simple series...
Following on from my experiments with the radio control receiver I still found myself unable to simulate the binding process. Everything I’d read suggested that a series of pulses needed to be sent just after power up, but the code in paparazzi that did this didn’t work for me. Capturing the pulses The starting point was using the existing AR8000 as when this is powered up with a bind plug inserted and the satellite receiver attached both go...
When I started updating the quad I didn’t expect it to be an instant process, but I didn’t really expect it to take as long as it is taking me 🙁 The delays are due to a number of reasons, but the time it takes for some orders to arrive certainly is a large contributor. Radio Control I’ve been using a Spektrum DX8 for radio control and with the previous board The individual “servo” leads were connected directly...
I’ve spent a bit more time with both Paparazzi and the KroozSD board, so these are a few more observations. NB these ONLY apply to the KroozSD board 🙂 Configuration After a good look through I changed the settings to match my configuration, tweaked a few to what I hoped would be more appropriate values and rebuilt. The ESC’s now make the correct noises and the telemetry looks good. The battery voltage being shown is that supplied via the...