ShrimpBot v1.6

SAMSUNG

I’ve uploaded an updated version of the ShrimpBot template to ThingiVerse.

#Changes from V1.5 to V1.6
1) Larger wheels, if they are turned 360° in opposite directions bot will turn 360°
2) Option to mount motors on outside
3) 2 internal supports added

 

The new internal mounts help with stability and also give another mounting point for the motors

SAMSUNG

 

 

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Levelling the new curriculum

One aspect of teaching ICT I used to struggle with was levelling. More specifically getting students to understand what level they are working at and how to improve on that level. I spent a lot of time integrating levels into my teaching and to my resources.

Last year I decided to try to create some general purpose resources based on key words rather than complete level descriptors. One of these resources that worked well where my level dice, these had levels 3 to 8 on each side with a series of keywords to match each level. If students are completing written work (mainly evaluations) I have these on the desks and encourage them to try and use the key words. I also use them for questioning, students pass the dice around and have to try to describe what they did/learnt during the lesson using the highest level number they can. Other times I will show some examples of student work on the board and have each table try to give them a level using the dice.

I think this resource worked well because it was simple, re-useable and could be applied to a range of topics.

Level Dice

You can download the dice template here if you want

With the move to a new curriculum I’m now teaching Computing, Programming, Robotics and Computational thinking (to name a few). I am now looking at how to effectively level students  and how to get them to understand these new levels. CAS have provided a suggested curriculum complete with level descriptors that is proving quite useful as a starting point .

The question I am now asking is do I need to add new KeyWords to my Dice (and other resources) or do I need to create some new dice for this new curriculum.

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ShrimpBot parts

I thought for my first blog post I would add some details of the parts I’m using for the #ShrimpBot project. You can see videos of the shrimp bot here

Since I first came across the very low cost “Shrimping It” Arduino clone (HTTP://shrimping.it) I have been working on a project to create a low cost robot (ideally under £10). This has led to the development of the ShrimpBot. So far I have had this chassis working with a Shrimp, an Arduino and a Raspberry Pi.

The main component is the chassis, the template is available at HTTP://www.thingiverse.com/thing:36062. This site contains the latest laser cutter templates and assembly instructions.

I have made versions of this using 3mm perspex and 3.5mm plywood. While the perspex looks cooler the wooden version is cheaper, less likely to break and is easier to attach other items to. To keep costs down the wheels for the robot are cut out of the same material

SONY DSC

There are lots of options available for robot motors, for the shrimpbot my priories where price and ease of use. For the current ShrimpBot design I have used a small motor and gearbox unit avaliable from Rapid in 1:200 and 1:120 geared ratios. You can also buy them from ebay but you need to be careful as the prices vary greatly. Last time I bought motors I got them from here

Using a motor and gearbox means that you don’t had to slow down the motors down using PWM and makes the robot easier to control, the disadvantage is you can’t speed up the robot either.

Assembly of the robot requires some double sided sticky tape (available from your local pound shop) and some superglue for the perspex version.

SONY DSC

Once assembled you can control the robot chassis you will need to control it. It is possible to power the motors directly from an Arduino but as the outputs have limited power it will run slowly, it is inadvisable to connect the motors directly to a Raspberry Pi’s GPIO ports.

Ben Smith @ManchesterBudo  http://smithyaks.wordpress.com/ has done some work on using transistors to control the motors.

If you want to turn the motors in both directions then you will need a motor controller. My current ShrimpBots use an L298 motor controller unit (about £3.50 on ebay)

L298The advantages of this unit are that it is easy to wire up and you can use a separate power supply for the motors.

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