Displaying Raspberry Pi Truetype Fonts


I’ve been enjoying tinkering about with AdaFruit’s PiTFT 2.8″ touchscreen for the Raspberry Pi.  Working out how to display text and graphics on the screen using the frame buffer with, Python, my programming language of choice.  It took little research to get text to display on the frame buffer.  It took a little more to work out how to identify and list installed Truetype fonts. So I thought I’d post the code I used to list the Truetype fonts installed on a Raspberry Pi in case it proves helpful to others. Continue reading

Raspberry Pi Photo Frame


Our last digital photo frame died a little while ago.  I did some research for a replacement and decided that none really did what I wanted.  Plus, this sounded like a perfect project. The most obvious candidate for the heart of the project is the Raspberry Pi.  There are lots of options for suitable screen from small to large TFT panels.  However, this version is intended as a proof of concept & so keep the costs down in case it turns out to be a disaster.  Adafruit do a fantastic little 2.8″ touch screen TFT panel that nicely mounts onto the Raspberry Pi GPIO.  Both can be enclosed in a variant of the lovely PiBow case. Finally, the project needed to run over WiFi so it could be positioned anywhere in the house.  If this project proved successful a larger screen could be purchased and this little touchscreen could be used for all sorts of other things.

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Review: AVR ISP Shield Kit for Arduino

AVR ISP Shiled

AVR ISP Shiled

I’ve had the pleasure of using ATtiny85 devices on previous projects like the ATtiny85 Christmas Bauble. I’ve had some ideas for some more projects but distractions have meant quite a long absence from the soldering iron; damn you Skyrim!

One of the things I’d planned to do was to make a shield for programming these devices rather than lashing them up each time on a breadboard. It’s a relatively easy circuit so the shield would not have been too difficult to produce. However, in the mean time I discovered that Phenoptix have produced the AVR ISP Shield Kit for Arduino. A kit of parts including a bespoke PCB for a price lower than I could have created a Veroboard version. Their version allows the programming of a range of similar devices, which my version wouldn’t have supported. I purchased and the kit was speedily delivered and well packaged.
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StripDuino Shield Mk1

StripDuino Shield

This post details the design for the shield for use with the StripDuino Mk.2 Arduino clone.

This shield could be used for many things.  My first shield will incorporate a L293D for driving some motors for our first robot project.

Hopefully there will be plenty more uses in the future.

The design brings out all of the ATMega328′s pins except the Analogue Reference (AREF).  It provides regulated +3.3V & +5V supplies. Continue reading

StripDuino Mk2

StripDuino Mk2

The StripDuino Mk1.5 had a number of flaws.  Mainly in that there was no mechanical design!  How was I going to mount it onto anything?  In working on rearranging the board to include mounting holes and another design that included the L293D for driving some motors I had some ideas for more improvements.  Instead of making a complete board for each project, why not create the StripDuino board plus a shield design?  Then I can make endless shields without having to re-make the processing part each time. Where have I seen this idea before?

So, this version includes the following improvements:

  • Female header sockets for the StripDuino Shield (see future post)
  • Mounting holes
  • +3.3V Regulated Supply
  • DC Power Jack connection

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Arduino Theremin

Wikipedia …

The theremin originally known as the ætherphone/etherphone, thereminophone or termenvox/thereminvox is an early electronic musical instrument controlled without discernible physical contact from the player.

It is named after the westernized-name of its Russian inventor, Léon Theremin, who patented the device in 1928. The controlling section usually consists of two metal antennas which sense the position of the player’s hands and control oscillators for frequency with one hand, and amplitude (volume) with the other, so it can be played without being touched. The electric signals from the theremin are amplified and sent to a loudspeaker.

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Gertboard Gallery

A few images of the assembly of the Gertboard for Raspberry Pi. Also, showing off the Olloclip Macro Lens for iPhone 5.

Raspberry Pi reading BMP085 Temperature & Pressure

Figure 1 – BMP085

Another fun little i2c device acquired cheaply via eBay.  It reads barometric pressure and temperature.  There’s some relatively simple maths to convert the outputs to something readable.

Once again, ADAFruit provide a fantastic guide and library for using the device in their Using the BMP085 with Raspberry Pi.  As in previous posts, I could have just used the ADAFruit library out of the box.  Whilst I do not feel the need to re-invent the wheel and re-code from scratch, I do like to have an understanding how it works. Continue reading

Programming an ATtiny85 with an Arduino Nano


First question for anyone reading this … why?  Well, I’ve a few ideas for using this tiny microprocessor.  There’ll be a post along very soon after this one.

Here’s the datasheet for this fantastic device.

Just about all the information needed to do this can be found in High-Low Tech’s Programming an ATtiny w/ Arduino 1.0.1.
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Pelican Crossing – Part 2: I2C MCP23017 & 555

Figure 1 - Working Breadboard Prototype

In Pelican Crossing – Part 1 software threads were used to provide timing to both the lights and the buzzer at the same time.  In Part 2, the I2C MCP23017 is used again but instead of using software to time the operations, the intermittent buzzer is implemented in hardware using a 555 timer.  This simplifies the code but makes the hardware more complex.  I learned something from both versions.

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