Let's Make Robots!

Workshop basics - working with templates

Just a quick entry to cover a point asked by Antonio about using templates.

I'll use an example of some leg components from a hexapod that I am working on currently. Here is how I made them to be accurate to each other, and also accurate to the design. I'll add pictures to this post when I get home.

The component is a joint between two servos, and is a complex shape - A circular section at the end of each joint with a curved centre brace between the two.

I will post a picture of it at some point, but it's essentially the middle leg joint of a bot like this:

Workshop basics - the mechanical side of robots - post 1

Given the fact that I'm stuck in the middle of 3 months of 75 hour weeks, and Mrs Steve is *still* grumpy becuase there are no tiles on the kitchen wall, it looks like I'm not actually going to be able to build robots for a while, so I thought I would write about some area's instead.

I have found LMR's blog roll one of the most useful places to learn about robots and robot building, and so I thought I would add something myself.


Tank tracks. Sources? Theory?

Hello all.


I am looking at tank tracks at the moment, and I want to ask two types of questions.

Firstly - theory

I am looking for a rescource which explains stuff like the theory behind tank tracks. What does good and bad design like? For model robots, does it make sense to use bogie systems etc. I'm guessing there is a lot of stuff on the net, but no idea what to put into google to get the results back that I am looking for. 

Can anyone throw up any useful links?

Second - Sources.

Amps used - how to detect?

I want to set up a system to measure a set of motors which will be making their way into a robot.


I want to vary the voltage in, and then vary the load on the motor, and measure the amps used.

Voltage in control is easy. As is putting load onto the motor. Measuring the amps seems less easy.

I have found a couple of schematics for such a circut, but they are using shunts, with costs up to £45 a piece.


Am I looking at the wrong thing? Can someone point me in the right direction of a schematic that might help?



heading lock gyros for hexapods - looks to bounce around idea's

Hello all.

I am currently playing with a hexapod design ( 2DOF ) using an audrino board. This may well end up shifting to a Proppeler board, so please bear both in mind.


I have currently got my pod walking, but in an entirely hard coded way "move leg 1 by x degrees" etc etc. Next step is to get the gyros  and accelerometers in, and get it self correcting.


We've tried a couple of different gyros now, and they are noisy things - there is a fair amount of messy data and a lot of outlying data points.

Looking for design patterns and ani-patterns



I'm struggling to find a good rescouce which collects together all sorts of different proven patterns and anti-patterns.


For example, a whole section on different leg designs - laying out the mechanics, some of the main statics behind the design, thinking about materials etc. No a specific design, but a load of proven designs. Ideally also anti-patterns - commonly thought of designs, but that are actually ineffective.


Boards usable with Java?

Can anyone point me towards any boards that I can program directly with Java, or that will run byte code?

I work on a day to day basis using Java/Scala/Groovy, and while I can handle stuff like Audrino C, and I'm just starting to learn Spin, I'm really missing being able to work in a grown up IDE with full tool chain to make life easy.

I have seen the Javalin Stamp, which can handle Java, but  it's a fairly limited board. I am really looking for something like a JVM aware Audrino, or a Propellor - that sort of scale of functionality.


Anyone used the Propellor system + Spin? Thoughts?

Just wondering if I can get some feedback on the Propellor system?


Specifically this one:



In theory, it's like a multi-core Arduino, but without the Analouge channels. I like the idea of lots of cores, it should make coding easier - less hassle with interupts. I can cope without Analouge, as there is always ADC available as a breakout board. You can also call on a 32Mb memory via a shield, which is also nice.

An evolving 2 DOF hexapod - build log

Hello all.


I'm going to use this blog as much as a lab book for myself and my partner as I am for fascinating and entertaining you guys, so if it rambles at time, I apologise in advance.


The basic premise of this build is to allow a platform that can be hacked apart and upgraded as needed - it's for learning, rather than a finished product. 


key requirements for Servos for walker robots? What can I sacrifice?

Hello all.


I am in the midst of building a six leg walker bot. I am following a set of designs I found posted on here. Initially, it will be a 2 DOF setup, but the plan is to use it as a test bed, and expand out to 3DOF, add sensors, add increasing complex algorithms etc.


I would like to keep the costs as low as I can initially, but the flip side is that I don't want to cost cut to the point of introducing significant issues into the build, which then takes a lot of additional coding to manage.