Learning about electronics with blinking LEDs - Page 1
Forum section: electronics / beginners

author: farsi
author_rank: Regular Contributor
timestamp: September 02, 2014, 11:11:05 am
content: Hi,to improve my working knowledge of electronics and Arduino, I have asked someone to build me a small PCB to work/program a number of LEDs.The resulting board is:https://oshpark.com/shared_projects/ZsQu0dA9Now, I was wondering, if I would repeat the experiment, what could be interesting for others to use the board with LEDs?The 74HC595 shift register is already nice, but maybe there are better/other shift register approaches to drive LEDs? Maybe there are other LEDs, e.g. RGB LEDs? Or, I should make the board compatible to use as light detector/sensing device.I hope that this board can help others too, to learn about electronics/hardware from a software perspective. What would you think could make the board interesting for this?Thanks!

author: farsi
author_rank: Regular Contributor
timestamp: September 02, 2014, 11:13:48 am
content: Also, I would like to learn more about the working of protocols such as SPI and I2C - what should be added to enable this kind of learnings?

author: Rerouter
author_rank: Super Contributor
timestamp: September 03, 2014, 11:13:21 am
content: I would probably say dont try and cover everything with one board, SPI and I2C are very different beasts to just shift registers in that they use addressing and registers, and some devices require values to be written to setup registers before they will even respond to anything else,You could still take your shift register board and challenge yourself by using the shift register to control 5 RGB leds (3 colors and 5 enables), by using direct pin writes it would be more than easy to not only make it appear as if all 5 were on at once, but if you really wanted to push it could possibly get say 4 bits of PWM by loading the shift register with new data fast enough, (5x 4x 60Hz = 1200 updates per second), or 9600 pin toggles, which gives you over 1600 clock cycles per update to play with what you want to do in the next updateAs for where to head from here, yes you could defiantly go for a light / colour sensor as i would imagine a large number of the sensors would use i2c or similar to read out the data from them, or grab a cheap 10 DOF (Degrees of freedom) board with accelerometers, gyroscopes etc, as you get to play with the sensors and they also have a ridiculous amount of settings which means you can dig in and figure out how to set it up etc,as for i2c / spi I/O expanders, i have not touched them myself for no other reason than i have not yet needed them, they have some merits, but short of more advanced peripherals like additional PWM / adc's, i fail to see the need for more than shift registers,

author: farsi
author_rank: Regular Contributor
timestamp: September 03, 2014, 11:58:38 am
content: thanks for sharing the ideas.indeed, someone pointed me to look at the Sparkfun digital Sandboxhttps://www.youtube.com/watch?v=2zZkeeQr49g&feature=youtu.be- which is close to what I want to do too.But indeed, for me the most fun part is the LED blinking and avoiding frustrations with wiring the breadboard as soon as you hit a larger number of LEDs. Also wiring a shift register on a breadboard was not exactly fun, this is why I was looking into a PCB setup.Good point on direct contact with the LEDs vs. control by shift register. I'll look further into some options there.

author: Alex30
author_rank: Regular Contributor
timestamp: September 03, 2014, 01:20:15 pm
content: I disagree that a PCB would take out the headaches of learning with a breadboard, personally I think wiring something up on a breadboard is a rewarding experience when you set it up yourself. The other thing is that buying\etching a PCB every time you want to test something new is extremely time consuming and expensive. Get yourself a breadboard and start experimenting!If you are looking to start using a lot of LEDs I would get a package that already has common anode\cathode set up such as this:http://www.ebay.com.au/itm/Matrix-8x8-RGB-LED-Full-Color-Dot-Square-Display-60x60mm-Common-Anode-Arduino-/221267545445?pt=AU_B_I_Electrical_Test_Equipment&hash=item338492cd65&_uhb=1I know it says arduino but if you look at a standard datasheet you can see how it's wired up:http://www.seeedstudio.com/wiki/60mm_square_8*8_LED_matrix_-_super_bright_RGBBy applying voltage\ground at the pins noted in the schematic you can get it working. Just be sure not to overdrive these LEDs (I have accidentally blown one before by applying +5V)Also if you have a big enough breadboard you can actually plug this matrix directly into it.

author: farsi
author_rank: Regular Contributor
timestamp: September 03, 2014, 02:02:49 pm
content: thanks - the seeeduino project looks interesting (besides the LED matrix). it's almost like a tiny ATmega motherboard integrated with components for experiments.funny how this evolves into building a small rendering device, this becomes quickly clear by seeing the LED matrix.