Author Archives: leonyuhanov

Detailed Comparison of High Speed Voltage Level Shifting

This is a detailed comparison of Voltage Level Shifting from 3.3V logic to 5V logic, specificly for driving Addressable pixels.

In this test I used an ESP8266 set up to transmit data at different frequencies over the SPI port.

The top 5 screenshots use a single SK9822 pixel.

The bottom screenshots use the SN74HCT245N.

5 Diferent SPI frequenies were tested: 1Mhz, 5Mhz, 10Mhz, 15Mhz & 20Mhz.

The SK9822 pixel is consistently over 4.5V BUT at 15Mhz and UP drops to 4.4 and 3.7 which becomes useless. However the The SN74HCT245N is consistently between 5.3-5.3V even at 20Mhz. I did not test at a faster rate because the SK9822 pixel has a maximum “imaginative” rate of 30Mhz, although driving strands longer than 100 pixels becomes impossible without serious RF insulation. The APA102 pixel, on which the SK9822 is based, has an maximum rate of 20Mhz Which is almost impossible to reach.

Project ideas

This could be an interesting wearable?

 

Experimenting with cheap Power Banks

I recently tried this product:

$_12

its an SBEC you can get details here 

I wanted to get 5V with high current out of simple 10-20Ah power banks like these

For this test I have 4 power banks. Each one has 5 x 18650 LION batteries in parallel, I opened up each one and soldered a cable onto the GND and +V Rails that run to the batteries:20160515_142749

I then sealed them back up and added JST plugs onto each battery. Thi sway they can be removed and recharged individually using their own charging cables:

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I then Connected 2 modules in series and connected 2 of these in parallel via a switch to the SBEC:

plugup

For the moment i have not had anything taking out more than 6A from the SBEC. Ill perform more tests as I test more LEDs at the same time!

 

 

 

New tiny parts

In the never ending quest to find a Voltage level shifter, to drive addressable LEDs, I found myself looking at these http://www.ti.com/lit/ds/symlink/sn74lvc2t45.pdf . These ICs can do 3.3V to 5V translation for 2 pins at a whooping 420Mbit and they cost $80c (USD) . So I ordered 5 from TI….

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Yep… that’s damn small. Not sure how I’m going to use those… I have no Surface Mount skills or equipment..Should have read the damn data sheet properly. Anyway, I’m glad there are 5, I will try my damn best to solder those pins to some larger pins and if i break any ill have a few extra to play with. If they work, ill be able to eliminate the Driver Pixel that i use in most of my application, most importantly ill be able to properly test higher data rates for the APA102 and the SK9822 pixel.

Next on the list are these $4 single cell Power Banks:

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These use a single 18650 to produce 5V at a maximum of 1A… With one more nice feature. They don’t have a power button. They activate simply when a load is detected. I’m using this as a test bed, and in a very non recommended way, I’m sure. I have the Output ports of all 4 into 1 Female USB port and was successfully able to power one of my latest creations:

 

Lots of hexagons

I have been hard at work on this new piece, for which i have not yet come up with a name..

It is constructed with 20 Hexagonal pieces. Each laser cut out of clear perspex. Behind each is a grid of APA102 LEDs all controlled by an ESP8266

Debounced switches

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I have been working on some physical interaction methods with my animations. This is the final version of the pushbutton board for a new project. It has 6 pushbuttons permenently connected to Gnd, the outputs default to Gnd and are fed back to the microcontroller. When a button is pushed, 5v is fed to the output, bur doesnt short out the feed. I use a diode and resistor in series in each button to achieve this. 0 bounce when the button ia pushed combined with a digital read method that does a quick sweep of all inputs

Lets cover a car in LEDs & GSPF 2016

A friend asked me a while back…

“what would it take to cover an entire car in these LED pixels?”

He even went so far as to give me a die cast model of a Ford Mustang GT to play with

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So I did

Now this is just a prototype for a large scale version. Covering a life sized car with LED pixels would be an epic effort I would love to undertake, but it would require some hefty funding. Not to mention someone donating a car to me… The car above used WS2812b pixels. I had a bunch of them lying around from another prototype that I had dismantled. No sense in binning these pixels if they can be reused.

The Gertrude Street Projection Festival is happening again!!! This year, I have decided to enter. Not with a car covered in LEDs, however. But with the new WOW Suit! Id love to put it on a mannequin and have it displayed inside a shop window. I have some ideas for new animation sequences that would cater well for a shop front

White Night 2016 – The Wow Suit

White Night 2016 in Melbourne may not have been as huge as in previous years, but I sure had a blast. I walked around the Melbourne CBD and surrounds for about 7 hours and got my photo taken by A LOT of people! Everyone I ran into seemed to enjoy themselves and really liked the Wow Suit. Here are a few pics from the evening

I had a friend shoot some really good video of the suit, but until I get my hands on it, here is some from my Instagram:

Notice how the Official White Night Instagram account tells me to apply for an art grant next year, even though they sent me a Generic “NO THANKYOU” when I applied for this years event.

One more:

The Wow Suit @whitenightmelb !! #whitenightmelb2016 #whitenight #whitenightmelbourne #whitenightmelb

A video posted by Elec Dash Tron Dot Org (@wow_elec_tron) on