Tag Archive | "assembly"

Kit review – Evil Mad Science Larson Scanner

Hello readers

Time yet again for another kit review. Today’s kit is the Larson Scanner from Evil Mad Science. What a different name for a company; their byline is “DIY and open source hardware for art, education and world domination”. Art? Yes. Education? Definitely. World domination? Possibly – you could use the blinking LEDs to hypnotise the less intelligent world leaders out there.

Anyhow, what is a Larson Scanner? Named in honour of Glen A. Larson the creator of television shows such as Battlestar Galactica and Knight Rider – as this kit recreates the left and right blinking motion used in props from those television shows. For example:

The kit itself is quite inexpensive, easy to assemble – yet can be as complex as you want it to be. More about that later, for now let’s put one together and see how it performs. There are two versions of the kit, one with 5mm clear LEDs and our review model with 10mm diffused red LEDs. The kit arrives inside a huge resealable anti-static bag, as such:

1ss

Upon opening the bag we have the following parts (there was an extra LED and resistor, thanks):

4ss

… the PCB:

3ss

… which is nicely done with a good silk-screen and solder mask. And finally:

5ss

A very handy item – a battery box with power switch. The kit is powered by 2 x AA cells (not included!). And finally, the instructions:

2ss

At this point you can see that this kit is designed for the beginner in mind. The instructions are easy to read, clear, and actually very well done. If you are looking for a kit to get someone interested in electronics and to practice their soldering, you could do a lot worse than use this kit. Construction was very easy, starting with the resistors:

6ss

followed by the capacitor and button:

7ss

then the microcontroller:

8ss

… no IC socket. For a beginners’ kit, perhaps one should have been included. Next was the battery box. Some clever thinking has seen holes in the PCB to run the wires through before soldering into the board – doing so provides a good strain relief for them:

9ss

… and finally the LEDs. Beginners may solder them in one at a time:

10ss

however it is quicker to line them up all at once than solder in one batch:

11ss

… which leaves us with the final product:

13ss

Operation is very simple – the power switch is on the battery box. The button on the PCB controls the speed of LED scrolling, and if held down switches the brightness between low and high. Now for some action video of the Larson Scanner in operation:


Well that really was fun, a nice change from the usual things around here.

But wait, there’s more… although the Larson Scanner is a good training kit, it can also function in other interesting ways. The kit is completely open-source, you can download the PCB layout file, circuit schematic and microcontroller code. Get two or more and link them together to make a really wide LED display – expansion instructions are available from here. If you solder in a 6-pin PCB header to the area marked J1 on the PCB, you can reprogram the microcontroller using an STK500-compatible programmer.

After sitting my Larson Scanner next to the computer tower for a few minutes, I had contemplated fitting it into a 5.25″ drive bay to make my own Cylon PC, however that might be a little over the top. However my PC case has some dust filters on the front, which would allow LEDs to shine through in a nicely subdued way. Mounting the Larson Scanner PCB inside the computer case will be simple, and power can be sourced from the computer power supply – 5V is available from a disk drive power lead.

If you are going to modify your PC in a similar fashion, please read my disclaimer under “boring stuff” first.

The Larson Scanner can run on 3.3V without any alteration to the supplied components. What needs to be done is to use a voltage regulator to convert the 5V down to 3.3V. My example has used a 78L33 equivalent, the TI LP2950 as it is in stock. The power comes from a drive power cable splitter as such:

splitss

You may have a spare power plug in your machine, so can tap from that. 5V is the red lead, and GND is the adjacent black lead. Don’t use yellow – it is 12V. It is then a simple matter of running 5V from the red lead to pin 1 of the regulator, GND from the Larson Scanner and PC together to pin 2, and 3.3V out from the regulator to the PCB 3.3V. Insulation is important with this kind of work, so use plenty of heatshrink:

ldo1ss

… then cover the whole lot up:

ldo2ss

Now to locate a free power plug in the machine. It has been a while since opening the machine – time for a dust clean up as well:

ldo3ss

Mounting the PCB is a temporary affair until I can find some insulated mounting  standoffs:

ldo4ss

However it was worth the effort, the following video clip shows the results in action:


So there you have it. The Larson Scanner is an ideal kit for the beginner, lover of blinking LEDs, and anyone else that wants to have some easy blinking fun. You can buy Larson Scanner kits in Australia from Little Bird Electronics, or directly from Evil Mad Science for those elsewhere.

As always, thank you for reading and I look forward to your comments and so on. Furthermore, don’t be shy in pointing out errors or places that could use improvement. Please subscribe using one of the methods at the top-right of this web page to receive updates on new posts, follow me on twitter or facebook, or join our Google Group for further discussion.

High resolution images are available on flickr.

[Note – The kit was purchased by myself personally and reviewed without notifying the manufacturer or retailer]

Posted in evil mad science, kit review, larson scanner, learning electronics, tutorialComments (0)

Kit review: Freetronics KitTen Arduino-compatible board

Hello everyone

Within this article we are going to examine another new kit available from Freetronics, a company formed to provide many interesting Arduino-based products after the publication of the book “Practical Arduino” by Jonathan Oxer and Hugh Blemings – which in itself is a good read, there are many interesting projects to make and learn from.

Today we examine their answer to “is there a kit version of the TwentyTen Arduino Duemilanove-compatible board?” – by assembling their KitTen. Some people may be wondering why one would want to build a KitTen instead of an assembled unit. Personally I could think of the following reasons:

  • It’s fun to make something and see it work;
  • You can save over Au$10;
  • There are a lot more smoothing capacitors in the KitTen design than normal boards;
  • There is a dedicated 3.3V 100 milliamp power regulator (twice the current of the usual board’s 50mA supply)  – ideal for running thirsty shields that need a native 3.3V;
  • The board is for a project that needs to use a modified version of the TwentyTen/Duemilanove;
  • You want a board with a native serial instead of USB interface;
  • All that lovely prototyping area above the microcontroller;
  • The power light and LED for D13 are always visible due to their location on the edge of the PCB;
  • You could solder in your microcontroller to avoid theft – great for school and public use (Yes, this has happened)…

And so on. Moving forward, opening the KitTen package reveals the following:

contents1ss

Once again with a Freetronics kit, all instructions are included in colour, as well as the circuit schematic and another sheet explaining how the KitTen will work with Arduino systems and the specifications. The PCB is solder-masked and silk-screened with a very informative layout:

pcbss1

The rest of the included components shipped in an anti-static bag, including labelled resistors and an IC socket for the microcontroller:

contents2ss

By following the included detailed instructions, everything went well. The layout on the PCB is detailed with all component values, which makes life easier. Starting with the low-profile components:

solder1ss

… followed by higher-profile components such as the IC socket and capacitors:

solder2ss

… and finally the shield sockets. Instead of trying to balance them, it is a lot quicker to place the sockets on an existing Arduino shield, turn it over, drop the KitTen on top then solder the pins in:

solder3ss

Then finally we are finished:

finishedss1

There are a couple of things to watch out for when using your KitTen. The first is to make sure you have the power-select jumper fitted correctly:

powerselectjumperss

Place it on the left pins (as above) to power your KitTen from the FTDI cable; place the jumper on the right pins to power from the DC socket. You should use a power supply of between 9 to 12 volts DC at one amp. The second item to take care with is the blue power LED. The supplied model was so bright it was like staring into the sun. You may wish to test your own one and possibly replace it for a duller version, or use some fine sandpaper to reduce the brightness of the included LED. To upload sketches to your KitTen you will need a 5 volt FTDI cable. As mentioned above, this can also power your board as well.

Overall, this is an excellent kit, and considering the price of doing it yourself – good value as well. To get your hands on this product– visit Freetronics’ website, or your local reseller.

Remember, if you have any questions about these modules please contact Freetronics via their website.

Higher resolution images available on flickr.

[Note – the kit assembled in this article was received from Freetronics for review purposes]

Posted in arduino, kit reviewComments (0)


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