Communicating with an Arduino on a Pi

Yesterday I wrote about how I managed to get an “Arduino” (or at least the AVR ATMega328 chip which powers one) attached to and programmed by my Raspberry Pi. However exciting a blinking LED may be, though, it’s not much use if the only way to change its behaviour is to completely re-program the chip. …

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Build an ‘Arduino’ on a Raspberry Pi

This is, after all, supposed to be a blog about Raspberry Pi. With all the stuff about Arduino and Atmel AVR chips, you might think I have wandered off. However, just to prove that Pi and ‘Duino work well together, here’s how I hand-built a board to sit on the Raspberry Pi GPIO pins and …

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Detective work on PiFace Control and Display

Having wasted all my free time yesterday on trying to find out how the PiFace CAD is interfaced to the Raspberry Pi, I thought I’d take a different approach today. When I was last working with SPI, I used my trusty Saleae Logic analyser to find out what was happening, so I thought I’d connect …

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Using the bcm2835 C library for SPI

Yesterday I used Gordon’s WiringPi library to successfully read analogue voltage values from an MCP3002 chip over SPI. My plan for today was to try and read data as fast as possible, to begin building one version of an ultrasonic “bat detector”. However, I got a bit distracted.. When I looked in detail at the …

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Reading analogue data on a Raspberry Pi using MCP3002

I got a bit disappointed with my little bus pirate yesterday. I’ll investigate how to update it to fix the odd SPI behaviour another time, but for now, its on to trying to read the MCP3002 SPI ADC chip directly using the Raspberry Pi. However, this one I’m going to do a bit differently. My …

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Another try at reading a MCP3002 ADC with Bus Pirate

A few months ago I got somewhat stuck trying to understand how to “join the dots” between the Bus Pirate and a MCP3002 SPI analogue to digital converter (ADC) chip. Finally I abandoned the effort and moved on to other things. More recently, however, I have succeeded in sending data to a MAX7219 LED matrix …

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Driving a 7219 LED matrix from a Raspberry Pi

Flushed with my success in getting data displayed on my cheap LED matrix using a Bus Pirate, I decided that the next step was to see if I could get it working with a Raspberry Pi. Looking around for useful resources to get me started I found: Understanding SPI on the Raspberry Pi from Gordon’s …

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Testing a MAX7219 LED array with Bus Pirate

After thinking about how to drive the MAX7219 LED array I built yesterday, it occurred to me that maybe this is an ideal time to get to the bottom of how to use the Bus Pirate board that I failed to use with a MCP3002 ADC chip. This time I was determined to get it …

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Building a MAX7219 LED array

Time for a bit more soldering, I think. I couple of months ago I bought a little MAX7219 LED array kit from ebay for a couple of pounds. They are all over ebay and aliexpress. As kits go it is very simple – a resistor, two capacitors, some sockets and some optional connectors. Soldering it …

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