Clichéd Kickstarter videos

I guess you’ve probably seen a lot of “niche hardware” Kickstarter videos. I know I have.

What do they all have in common?

The project creator walking down a hallway towards the camera. The camera is slowly moving backwards. The subject then walks past the camera. Well at least ALL the videos coming out of a couple of accelerator/incubators have that.

If not that, it is probably all still shots of the prototype with a lot of dissolves and wipes stolen from someones 1993 wedding video. Add a bit of jaunty stock music playing in the background and call it done.

That is not what I wanted. I wanted to be unique. I wanted CRT televisions. I wanted messy hand drawn labels. I wanted it to look like we had no idea how to make a professional video.

I think we succeeded. Especially on that last point.

The one part of the video I actually like the best is the close up product shot with the labels. Maybe that is because it is the most unique and unprofessional looking part. Maybe it is just because I invested so much time in making it.

It started with styrene tube, some paddle pop sticks, six stepper motors, A4988 stepper drivers and an ATTiny2313 board I had lying around.  Now I admit this was done very hackishly and if I had a Smoothieboard or a Tiny-G handy this would not have taken me all day to do.

The styrene tube was just slightly oversized to be a press fit on the stepper shaft.  So I heated it with a lighter and squished it in ever so slightly.  I then slipped a 3.5mm plug onto the other end.  The tube could now couple the Uzebox DTV to the stepper motor.  I also drilled a small hole in the paddle pop sticks so they could be screwed to the other stepper motor shafts.

Then came the slowest part of the whole thing.  Wiring up the six A4988 drivers dead bug style.  This took me a long time and, as I said earlier, a Tiny-G or something similar would have made my life so much easier at that stage.

Finally lots of Blu-Tack and a stack of scrap polycarbonate and it ended up looking like this.

dsc_1157

Now came the job of controlling the steppers in the dumbest way possible.  The six stepper controllers got wired up to PB0 through to PB5 on the Tiny2313.  The board had a MAX232 on it.  All I had to do was have the AVR read a byte from the UART and push it out PORTB.  The desktop PC could then feed it step commands out a terminal program.  The 57600 baud UART would therefore be controlling the rate of steps without having to program any AVR timers.

#include <avr/io.h>

uint8_t ch;

int main(void)
{
    UBRRH = 0x00;                       // Baud rate 57600
    UBRRL = 0x08;
    UCSRB = (1 << RXEN) | (1 << TXEN);  // enable UART
    UCSRC = (1 << USBS) | (3 << UCSZ0); // async 8n1

    DDRB = 0xFF;                        // Set as output to drive steppers

    while(1) {
        while ( !(UCSRA & (1<<RXC)) );  // Wait for UART RX ready         
        ch = UDR; 		         
        if (ch > 13) {                  // ignore CR/LF or lower
            PORTB = ch;
        }
    }
}

You don’t get AVR programs much simpler than that.

If I sent “010101010101” out the UART on the PC the AVR would make the first motor step at 2.88Khz.  That is 57600 baud, divided by 10 (8 data 1 start 1 stop), divided by 2 (“o1”).  If you want to step slower you send fewer 0->1 transitions. “00110011” would be 1.44Khz.

If I sent “020202020202” out the UART that would make motor two step.

Motor three = “0404”.  Motor four = “0808” and so on using some combo of ASCII chars that just had the correct bit toggling.

A spreadsheet was used to make a nice smooth accelerating s-curve for the motor paths.  This was cut and pasted into a text document that my terminal program could send out the UART.  Again Tiny-G would have calculated all that kind of thing for me and I just could have sent G-Code to the controller.

Finally I added one more little subtle detail.  The last stepper motor has discontinuities in its stepper sequence.  This makes it shudder and jerk.  I though it kinda just needed that extra unprofessional touch.

youtubelink
Click to see the long shot on the you tubes
uzedtvfullyoutubethumbnail
Click to see the full Kickstarter video

Tell me what you think.  Does the video look bad enough that it is obvious we wanted that look.  Or is it only bad enough that it really looks “just bad” and we should have done a better job.

 

Advertisements

Leave a Reply

Fill in your details below or click an icon to log in:

WordPress.com Logo

You are commenting using your WordPress.com account. Log Out / Change )

Twitter picture

You are commenting using your Twitter account. Log Out / Change )

Facebook photo

You are commenting using your Facebook account. Log Out / Change )

Google+ photo

You are commenting using your Google+ account. Log Out / Change )

Connecting to %s