Multi proyectos 0070

Now I understand that there are a few CAN implementations out there, but the more the merrier, right?

This one uses the MCP2515/MCP2551 chips like most of them do. It has a switchable CS pin so that you can use other SPI shields with it that might have hardwired D10 as CS.  It has a switch to draw power from the CAN Bus if desired, if you wanted to add a WiFi or Bluetooth shield for example.  And for newbies like me it’s an entirely through hole design making it an easy DIY project.

I’ve also written a library that’s a complete implementation of the MCP2515 SPI command set.  It doesn’t yet have any wrappers for filters or masks, but these are all accessible through the read and write commands.  I have a simple Init function that takes a bus speed and clock frequency and calculates out all the necessary bit timing parameters, which makes it pretty straightforward to setup and use.

The basic idea is having the lights on the Christmas Tree turning on everytime someone tweets “Merry Christmas”.

It’s still pretty much a prototype but you get the idea. Sometimes the live stream gets out of synch with the tweet overlays, but generally it stays on track.

The actual setup is really all based off a lot of relays running 12V 1W LED’s. I started out with 10W halogens and after a few burnt tree branches I decided to try and find an LED which gave off as little heat as possible! It also meant a 20Amp powerpack could run all 30 lights.

We measure resolution in the terms of the number of bits of resolution. For example, a 1-bit resolution would only allow two (two to the power of one) values – zero and one. A 2-bit resolution would allow four (two to the power of two) values – zero, one, two and three. If we tried to measure  a five volt range with a two-bit resolution, and the measured voltage was four volts, our ADC would return a value of 3 – as four volts falls between 3.75 and 5V.

AREF means Analogue REFerence. It allows us to feed the Arduino a reference voltage from an external power supply. For example, if we want to measure voltages with a maximum range of 3.3V, we would feed a nice smooth 3.3V into the AREF pin – perhaps from a voltage regulator IC. Then the each step of the ADC would represent 3.22 millivolts.

The protocol on the data line is simple and self-clocked. Here are the low-level details:

• Idle bus state: Low
• Start Bit: High for 10µSeconds
• 0 Bit: Low for 10µSeconds, High for 20µSeconds
• 1 Bit: Low for 20µSeconds, High for 10µSeconds
• Minimum quiet-time between frames: 30µSeconds

Each frame is 26 bits long and has the following format:

• Start bit
• 6-Bit Bulb Address, MSB first
• 8-Bit Brightness, MSB first
• 4-Bit Blue, MSB first
• 4-Bit Green, MSB first
• 4-Bit Red, MSB first

From this we can see that we have a color depth of 12 bits. Not terribly great, but this should still be plenty for our purposes. What is interesting is the Brightness field. This field acts a bit like a multiplier and enables smooth fade-ins and fade-outs.

Well with this post I reach the 10,000 mark, which is a lot of posts!
It have been fun and I hope that some of them have been helpful. Apart from the odd odd character most people here have a wicked sense of humor. Thanks Guys.

There are of course questions that continually crop up and I have developed a small list of both my own pages and those from elsewhere that I can use in the appropriate situation. So my Exhibition now is a copy of this list so far. Enjoy:-

USB devices are so common nowadays – wouldn’t it be nice to use one with your homebrew electronics projects? I wanted to use my compact USB-MIDIkeyboard with my homebrew synth circuits. It seemed a simple enough prospect at first – listen to the data output, press buttons, note the changes, and then program a microcontroller to turn those changes into something I could use (like basic serial MIDI data).

USB devices are so common nowadays – wouldn’t it be nice to use one with your homebrew electronics projects? I wanted to use my compact USB-MIDIkeyboard with my homebrew synth circuits. It seemed a simple enough prospect at first – listen to the data output, press buttons, note the changes, and then program a microcontroller to turn those changes into something I could use (like basic serial MIDI data).

USB devices are so common nowadays – wouldn’t it be nice to use one with your homebrew electronics projects? I wanted to use my compact USB-MIDIkeyboard with my homebrew synth circuits. It seemed a simple enough prospect at first – listen to the data output, press buttons, note the changes, and then program a microcontroller to turn those changes into something I could use (like basic serial MIDI data).

We’re unlikely to replicate this machining process but the solenoids are another story all together. Starting at about 3:30 you can learn about designing, building, and using these little marvels. They’re basically an electromagnetic cuff with a metal slug in the middle. The solenoid seen above uses a body milled from HDPE and wrapped with magnet wire. The slug in the center is steel, with a few rare-earth magnets at the top. When you run current through the coil it repulses the magnets on the slug, witch then strikes the xylophone key. Using a MOSFET and a protection diode, actuating them is as simple as sending a digital high from your microcontroller of choice.

We’re unlikely to replicate this machining process but the solenoids are another story all together. Starting at about 3:30 you can learn about designing, building, and using these little marvels. They’re basically an electromagnetic cuff with a metal slug in the middle. The solenoid seen above uses a body milled from HDPE and wrapped with magnet wire. The slug in the center is steel, with a few rare-earth magnets at the top. When you run current through the coil it repulses the magnets on the slug, witch then strikes the xylophone key. Using a MOSFET and a protection diode, actuating them is as simple as sending a digital high from your microcontroller of choice.

We’re unlikely to replicate this machining process but the solenoids are another story all together. Starting at about 3:30 you can learn about designing, building, and using these little marvels. They’re basically an electromagnetic cuff with a metal slug in the middle. The solenoid seen above uses a body milled from HDPE and wrapped with magnet wire. The slug in the center is steel, with a few rare-earth magnets at the top. When you run current through the coil it repulses the magnets on the slug, witch then strikes the xylophone key. Using a MOSFET and a protection diode, actuating them is as simple as sending a digital high from your microcontroller of choice.

It’s still unfinished here. It’s basically opening the communication between the arduino, scaling everything from 0-127 to be compatible with MIDI, then being routed through various CC’s to mac’s IAC driver, which passes the MIDI CC’s into Ableton Live.

So there you have it. A few things are missing, the LED’s still need to be added and tweaked, a problem with there not being enough power to illuminate the very demanding buttons, although I plan to resolve this with an external DC adapter though.

It’s still unfinished here. It’s basically opening the communication between the arduino, scaling everything from 0-127 to be compatible with MIDI, then being routed through various CC’s to mac’s IAC driver, which passes the MIDI CC’s into Ableton Live.

So there you have it. A few things are missing, the LED’s still need to be added and tweaked, a problem with there not being enough power to illuminate the very demanding buttons, although I plan to resolve this with an external DC adapter though.

It’s still unfinished here. It’s basically opening the communication between the arduino, scaling everything from 0-127 to be compatible with MIDI, then being routed through various CC’s to mac’s IAC driver, which passes the MIDI CC’s into Ableton Live.

So there you have it. A few things are missing, the LED’s still need to be added and tweaked, a problem with there not being enough power to illuminate the very demanding buttons, although I plan to resolve this with an external DC adapter though.