SparkFun AVC 2015 recap

Well, that could have gone better… SparkFun AVC 2015 is over and was an epic fail for G-Force 2.0, our entry this year. G-Force 2.0 was a minor update of our 2014 entry, which came in second place in peloton class. This year, the chassis was made from laser cut wood and was much smaller and lighter than last year, allowing me to use faster motors with lower torque. Other than that, the electronics and software were largely the same. I really don’t know why it performed so badly. The navigation was very unreliable and I’m wondering if it is because the compass was closer to the motors and the ground this time and maybe was picking up interference.



I didn’t have much time for testing before the event and that ultimately was the issue. I have the luxury of time now to do more testing before next year.



G-Force progress 3/23

This weekend I finished assembling and painting the chassis and I’m pretty happy with the results. It looks much better than the original version at least.

IMG_20150323_101644284The motors and ultra-sonic sensors are installed and everything is looking pretty tidy so far. I made custom 3D-printed mounts for the ultra sonics so that they would sit flush with the wood and to help secure them in place.


Now I need to take a step back and figure out the plan for the rest of the electronics.


G-Force progress

After a break of several months I’ve finally had my second attempt at a laser cut wood design and this time all the pieces did fit together! There were some gaps that needed filling so it wasn’t perfect, but it was close enough. Here’s a quick photo of the new chassis for my autonomous vehicle. I’m really pleased with the results and I can see that I’ll be doing a lot more work with laser cut wood. It looks much better than my attempts at manual wood-working!


Next steps will be to prime and paint the various parts before gluing everything in place, then I can get started on the electronics, which will be largely the same as last year.

G-Force 2.0 Concept

I had some time this evening to start playing around in Sketchup to design a rough concept for the next version of my autonomous vehicle. This time around, I’ll be using laser-cut wood rather than my own woodworking skills. One design goal is to make it easier to access the motors and electronics for repairs so I’m designing “access hatches” this time, which I plan to cover with 3D printed panels.

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Sparkfun AVC 2015 Rules Announced

If you haven’t already seen, Sparkfun just announced the rules for this year’s competition. It’s a shame there is no aerial course this year, but let’s face it; it was only a matter of time before there was a nasty accident.

There are still some details to be announced, such as the details around the special 150 point-earning short-cut. I’m definitely planning on entering again this year but probably need to wait until all details are available before I start designing a new bot.

Also this year there will be a battlebot competition. I’m intrigued by this but it is something I so far know nothing about so I think I’ll just be a spectator for this event.

Mini Dalek Gripper Arm

After a crazy few weeks and weekends working on a new software release at work, I finally have some time to play with my new 3D printer and get back to work on a hobby project I’ve taken on for my local maker space. We’re putting together a Rube Goldberg machine and my section will be based around my mini Dalek robot. The plan is to have the Dalek receive a ping-pong ball from the previous section and then transport it to the next section and release it. It sounded so simple to start with but I’ve been struggling with figuring out how to attach the gripper arm and servo to the steel tube that I was using for the plunger arm.

This morning I had time to design a custom mount in Sketchup and then 3D print it. I made a mistake with aligning the mounting holes on one side but it’s close enough and works really well. Here are some photos.

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The Darby Digger

andygrove   January 4, 2015   3 Comments on The Darby Digger

My Dad told me about the Darby Digger many years ago and I just saw another mention of it today and I thought I’d share it here. The Darby Digger was a steam-driven machine for ploughing fields. It was invented around 20 years earlier than the tractor that we are familiar with today. My great grandfather, Robert Hasler, helped build it. Here’s a photo of Robert Hasler driving the Darby Digger (around 1879).


This next photo shows the Prince of Wales who came to see a later version of the Darby Digger. Robert Hasler is standing in front in this photo. Early versions of the Darby Digger actually walked on six or eight legs but later versions used wheels.


I was looking for more information online this evening about this and was amused to find that is was picked up by Make magazine back in 2006 (

I was also amazed to see that someone built a fully working scale version of one version of the Darby Digger back in the 1970’s and took a video which is now available to watch on YouTube.

I can’t even begin to imagine how hard it would have been to create a machine like this, driven by steam power, in the late 1800’s.

First 3D Prints

andygrove   December 23, 2014   No Comments on First 3D Prints

I’ve been learning how to use Sketchup to design parts for 3D printing and have now printed my first useful part – a simple mount for an HC-SR04 ultrasonic sensor. There are plenty of designs I could have downloaded from Thingiverse, but I wanted to design my own as a learning exercise. Here’s the rendering of the design in Sketchup:


Here is the 3D printed part. This was a medium resolution print in PLA.


The ultrasonic sensor fits quite snugly, but I’d probably need to use some hot glue to secure it in place. This feels like a good first step in 3D design though.


First attempt at laser-cutting

On Black Friday, rather than spend time getting crushed in the sales, I spent the day learning how to use Inkscape to produce a design for laser cutting. The design I’m working on is a new chassis for my autonomous vehicle. I found this great video on YouTube which really showed me everything I needed to know to get started.

It was slow going to start with, but after a while I felt I was getting the hang of this. I sent my initial design off to Ponoko ($35 including shipping) and around two weeks later the end result arrived. Here’s a photo of the base and the sides. I was really pleased with the end result but unsurprisingly I made a couple of mistakes in the design, so I will have to do at least one more revision of this before I have anything usable.


Hopefully I’ll find some time over Christmas to make more progress on this.