Apr 102016

Ok, so remote means just a few meters away, either in the house or in the car. Somewhere warm anyway.

So, as mentioned in my previous post, I’d done a lot of research, and one of the things I came across was this video:

This is what I want to be able to do. I’ll never have the room for an actual observatory like this one, but I could at least automate a lot of the work. That’ll scratch at least two, maybe three, of my geek itches. Of course, everything has to be Linux based, and also as cheap as possible. With that, I decided on at least the following to start with:

  • AstroEQ – Definitely needed goto support on my EQ5 mount to start with.Fully made systems can be bought (minus steppers and mounting hardware), but I already had most of the parts laying around the place so decided to make it myself using an Arduino Mega
  • Indilib – This, running on a raspberry pi acts as a remote control server for anything that I wanted to add. All devices had to be supported, or easy enough for me to add with my limited programming skills.
  • Guide Scope – These are used to ‘lock’ onto a star and make sure that the telescope mount follows it precisely. Long exposures of up to even 30 minutes can then be achieved without too much difficulty. Initial plans are to try and use the Raspberry Pi camera (will try both standard and NoIR) versions.
  • Focuser – Last essential part for remote control is the ability to focus the telescope. This will use the DSLR attached and a stepper motor coupled to the focus knob. There are a couple of arduino based projects that emulate the MoonLite protocol, which is supported by indilib.

Once I’m happy with this lot (and I *will* blog my progress) and have some of my other projects finished (*cough* R2), then I want to take a look at a couple of other add ons such as:

  • Filter wheels – I can use kstars to take many photos with different filters in place, and also with a black filter I can automatically take dark frames for stacking images. (Dark frames are used to remove noise in the picture that is generated by the DSLR)
  • Auto lens cap – A simple servo driver to cover the telescope main lens. Not really necessary, but figured it would be a nice project.

I should be able to do all of this fairly easily. I already have most of the components necessary, and the software running on my workbench. One of the big issues I’ll need to work on is just how to mount it all to the scope and stop the cables getting tangled!

My next blog should be on building and configuring the AstroEQ.

Apr 052016

Hi, my name is Darren and I’m a serial hobbiest.

Well maybe not that bad, most of my hobbies are pretty much related (electronics, computers, science), and a lot are things I’ve been interested in since I was a kid. Most recently, I’ve invested in a fairly decent telescope and mount to do some visual astronomy, but more for astrophotography. I want to take pretty pictures of things very far away! So after a lot of reading of various blogs and websites (Star Gazers Lounge forum is fantastic), and watching numerous youtube videos, I got a tripod for my camera and a couple of cheap lenses off eBay. That is all that is needed and you can get some half decent shots.

My astrophotography album

But it wasn’t enough. So I dove back into the forums and did even more research, and learnt a few important things.

  • Telescope – Numerous different types, mainly split into reflectors, refractors, and catadioptric. All have their benefits and downsides, but for doing astrophotography the telescope isn’t the most important item surprisingly.
  • Mount – This, for astrophotography, is the most important thing to get right.You need to have a solid mount for doing anything more than a few seconds exposure, and one with tracking in Right Ascension at least, to track the stars. And it really needs to be an equatorial mount to avoid rotation of the starfield as it rotates.
  • Eyepieces – You need eye pieces to view through a telescope, and the shorter the focal length, the greater the magnification. These are generally only used for visual astronomy, as cameras bypass the need.
  • Camera – Most DSLR cameras block out a large part of the infra red by design, but you can get them modified to remove this filter and get much more vibrant images. Its not a necessity, but definitely a nice to have.

Whilst learning all this, I had a thought in my head about some form of computer control (Linux based, of course) and actually stumbled upon a few projects to help with this. The first was AstroEQ which was an opensource ‘Goto’ system (select a star, and the telescope will automatically move to center on it) designed around an arduino. That was a perfect start for me, and I was pretty sure I could get it working from Linux. Thats when I discovered indilib!

Indilib is an open source system for controlling all sorts of astronomical instrumentation, not just goto mounts, but also things like auto focusers, digital camera, filter wheels, and other custom devices you may want. Even better, all this can be run from a Raspberry Pi as the control server and a laptop using the actual astronomy software. This would mean I could set it all up, and retreat to somewhere a little warmer to actually do my observations and photography. I’m sure this is against the amateur astronomers code or something, but damn it gets cold out there.

Along with indilib, there is kstars. This is a planetarium program written for the K Desktop Environment, and with EKOS plugin can control any indilib hardware. Not only that, it can schedule work and sequences, and help you plan your observations.

I’m going to (try to) write more blog posts chronicling my progress on getting all this set up, and some HowTo posts on using indilib on a raspberry pi, with kstars, and any custom hardware I make.

Dec 092011

Over the past few months I’ve been slowly stocking up on all the equipment needed to properly get back into electronics. As I was gathering things together I discovered Arudinos. These are an easy entry into microcontrollers, much simpler in my opinion to PICs, and cheaper than most other developers kits. The fact that they’re open source and open hardware just seals the case. The standard Arudinos are rather nice to work with, but since messing with them on a few mini projects to teach myself about them, I came across a guy who was selling his own custom design, utilising the arduino bootloader and interface, but in a much smaller form factor and inbuilt wireless communications.

These JeeNodes are about the size of a pendrive, and have an inbuilt RF12B wireless module. Along with the nice hardware design, there are also some easy to use libraries, and a great website to accompany them, with lots of nice tutorials, information, and general geekiness.

Home Automation

So, where does home monitoring come into this? One of the addon boards that Jeelabs sell are little room monitoring nodes that detect temperature, humidity, and light level. Add a PIR and you’ve got a motion sensor too. The guy behind the JeeNodes, Jean-Claude Wippler, has done some great work on power consumption meaning that these room nodes can run off a single AA battery for nearly a year. There are about a dozen or so of these nodes now spread across my house, logging into a database, and I’ve done some basic graphs to display the data.

Home Automation

Now I’d also noticed another project using arduinos to monitor electric consumption that was also based on JeeNodes, and reporting back to a central server to log into a database. This got me thinking, could I combine these, and maybe more. The beauty of open source is the fact you can tweak and edit to your hearts content. The fact that both these projects used JeeNodes, and more importantly, the RF12B library from JeeLabs, means that I only need one receiving station and a few small edits to the nodes.

To the transmissions I added a node type to the beginning of the data. This defined whether the node was a room node, power node, or any other future node types I may define. Most of the rest of the code was left untouched, except to assign a node number to each node. That was the easy bit.

Next I needed a receiving station, and some way to get the data it received into a database. For this I once again turned to the JeeNode. Handily, JeeLabs also sell a nice case for the JeeNode, along with a Ethernet add on. This gives me a very small self contained module that simply needs power, and an ethernet connection. Both the energy monitor project, and the room node project had their own code for a base station, and for getting the data into the database. In the best traditions of open source, I have stolen from both these projects and combined my favourite ideas out of both.

The houseNode sits and listens for any broadcasts from any nodes. It knows about the different types of nodes, and the data structure to be expected for those nodes. When a data packet is received then the node type is stripped out, and the rest of the data put into a structure definition depending on the type. Then a JSON structure is constructed, and sent via HTTP POST to a web server. No acknowledgements of data being received are currently sent, but with future expansions that I have in mind, this will be a requirement.

Home Automation Home Automation

The web server will receive the POST command, and basically dump this information into a database. From this database, a front end can draw graphs and report on anything you want. The front end is very much still in construction, but can be viewed at http://home.22balmoralroad.net/

Future developments I am considering are a thermostat node, to control our central heating, and RFID entry/exit nodes to log in and out of the house. The RF12B modules have a limit of 32 addresses, two of which are reserved. However, 30 nodes should be enough for most of my ideas! It does have the other benefits of very low power, very simple, and the JeeLabs library even has encryption built in. Below are the Arduino sketches for each of the nodes.