Using an H bridge to reverse the polarity of DC motors is something I have never attempted before but will be really useful, not just in this project, but for major too. I've started adapting existing code from other users for my own needs, essentially all I need for the projectors to move is: 2 x 12v motors, 1 x arduino, 1 x H-bridge and 1 x 12v power supply.
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This H-Bridge diagram was extremely useful in helping me wire it up, this is a good reference point to come to in future projects. The +5v is supplied by the arduino while the +12v is from the adapter running from the mains which drives both left and right motors. The digital pins from the arduino either side of ground and motor pins can run from any of the digital pins and control the polarity of the electricity entering the motors.
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This H-Bridge diagram was extremely useful in helping me wire it up, this is a good reference point to come to in future projects. The +5v is supplied by the arduino while the +12v is from the adapter running from the mains which drives both left and right motors. The digital pins from the arduino either side of ground and motor pins can run from any of the digital pins and control the polarity of the electricity entering the motors.
// ————————————————————————— Motors
int motor_left[] = {2, 3};
int motor_right[] = {7, 8};
int ledPin = 13; // LED connected to digital pin 13
// ————————————————————————— Setup
void setup() {
Serial.begin(9600);
// Setup motors
int i;
for(i = 0; i < 2; i++){
pinMode(motor_left[i], OUTPUT);
pinMode(motor_right[i], OUTPUT);
pinMode(ledPin, OUTPUT);
}
}
// ————————————————————————— Loop
void loop() {
drive_forward();
delay(1000);
motor_stop();
Serial.println("1");
drive_backward();
delay(1000);
motor_stop();
Serial.println("2");
turn_left();
delay(1000);
motor_stop();
Serial.println("3");
turn_right();
delay(1000);
motor_stop();
Serial.println("4");
motor_stop();
delay(1000);
motor_stop();
Serial.println("5");
digitalWrite(ledPin, HIGH); // set the LED on
delay(1000); // wait for a second
digitalWrite(ledPin, LOW); // set the LED off
delay(1000); // wait for a second
}
// ————————————————————————— Drive
void motor_stop(){
digitalWrite(motor_left[0], LOW);
digitalWrite(motor_left[1], LOW);
digitalWrite(motor_right[0], LOW);
digitalWrite(motor_right[1], LOW);
delay(25);
}
void drive_forward(){
digitalWrite(motor_left[0], HIGH);
digitalWrite(motor_left[1], LOW);
digitalWrite(motor_right[0], HIGH);
digitalWrite(motor_right[1], LOW);
}
void drive_backward(){
digitalWrite(motor_left[0], LOW);
digitalWrite(motor_left[1], HIGH);
digitalWrite(motor_right[0], LOW);
digitalWrite(motor_right[1], HIGH);
}
void turn_left(){
digitalWrite(motor_left[0], LOW);
digitalWrite(motor_left[1], HIGH);
digitalWrite(motor_right[0], HIGH);
digitalWrite(motor_right[1], LOW);
}
void turn_right(){
digitalWrite(motor_left[0], HIGH);
digitalWrite(motor_left[1], LOW);
digitalWrite(motor_right[0], LOW);
digitalWrite(motor_right[1], HIGH);
}
Film Edit
I've got the rushes back and they do look really nice, I don't particularly like what I have shot for some of it but it all looks nice, considering how dark and miserable the weather was when shooting it has come out really well. Editing is proving a nightmare though, it is so fiddly with only a bed, a splicer and a light bulb to help. I have separated up all the shots and labeled them, I've now got to try and start splicing them together into the two different loops. I need the corresponding points in each film loop that relate to each other to be the same distance in the loops if I am to stand any chance of them syncing at any time. I am doing this by starting from the shot where the two strangers make con tact at the edge of the frame and working from there, tacking the film as I go to judge the correct measurements. The edit sequence is being decided as I work through the films together, some shots will correspond to each other from different points of view, others will be unrelated in reality to the narratives but seemingly related in the films.
int motor_left[] = {2, 3};
int motor_right[] = {7, 8};
int ledPin = 13; // LED connected to digital pin 13
// ————————————————————————— Setup
void setup() {
Serial.begin(9600);
// Setup motors
int i;
for(i = 0; i < 2; i++){
pinMode(motor_left[i], OUTPUT);
pinMode(motor_right[i], OUTPUT);
pinMode(ledPin, OUTPUT);
}
}
// ————————————————————————— Loop
void loop() {
drive_forward();
delay(1000);
motor_stop();
Serial.println("1");
drive_backward();
delay(1000);
motor_stop();
Serial.println("2");
turn_left();
delay(1000);
motor_stop();
Serial.println("3");
turn_right();
delay(1000);
motor_stop();
Serial.println("4");
motor_stop();
delay(1000);
motor_stop();
Serial.println("5");
digitalWrite(ledPin, HIGH); // set the LED on
delay(1000); // wait for a second
digitalWrite(ledPin, LOW); // set the LED off
delay(1000); // wait for a second
}
// ————————————————————————— Drive
void motor_stop(){
digitalWrite(motor_left[0], LOW);
digitalWrite(motor_left[1], LOW);
digitalWrite(motor_right[0], LOW);
digitalWrite(motor_right[1], LOW);
delay(25);
}
void drive_forward(){
digitalWrite(motor_left[0], HIGH);
digitalWrite(motor_left[1], LOW);
digitalWrite(motor_right[0], HIGH);
digitalWrite(motor_right[1], LOW);
}
void drive_backward(){
digitalWrite(motor_left[0], LOW);
digitalWrite(motor_left[1], HIGH);
digitalWrite(motor_right[0], LOW);
digitalWrite(motor_right[1], HIGH);
}
void turn_left(){
digitalWrite(motor_left[0], LOW);
digitalWrite(motor_left[1], HIGH);
digitalWrite(motor_right[0], HIGH);
digitalWrite(motor_right[1], LOW);
}
void turn_right(){
digitalWrite(motor_left[0], HIGH);
digitalWrite(motor_left[1], LOW);
digitalWrite(motor_right[0], LOW);
digitalWrite(motor_right[1], HIGH);
}
This basic test circuit with a 9v battery and test dc motors worked really well, I just had to source the windscreen wiper motors and connect the 12v power supply and I should have a working circuit I can use to complete the project.
I managed to get two good, identical Nissan micra front windscreen wiper motors, they are low geared so they should give me a smooth slow movement whilst giving me plenty of power to move the projects. Another advantage to these motors is the cheap price and availability of them, if I blow one up which I thought had happened a couple of times, I should easily be able to get hold of another one exactly the same.
I have soldered together the proper circuit board having worked well through testing, I had a few problems initially but this was just a wiring issue which was quite quickly resolved thankfully. The turntable is really nicely weighted so rotating the weight of the projector is easily achieved by the motor, for which an attachment has been precisely engineered courtesy of Dave in the 3D workshop (who helped us out last year too) with the rollers I scavenged out of an old printer. I need to replicate this on another turntable with another project and motor.
Film Edit
I've got the rushes back and they do look really nice, I don't particularly like what I have shot for some of it but it all looks nice, considering how dark and miserable the weather was when shooting it has come out really well. Editing is proving a nightmare though, it is so fiddly with only a bed, a splicer and a light bulb to help. I have separated up all the shots and labeled them, I've now got to try and start splicing them together into the two different loops. I need the corresponding points in each film loop that relate to each other to be the same distance in the loops if I am to stand any chance of them syncing at any time. I am doing this by starting from the shot where the two strangers make con tact at the edge of the frame and working from there, tacking the film as I go to judge the correct measurements. The edit sequence is being decided as I work through the films together, some shots will correspond to each other from different points of view, others will be unrelated in reality to the narratives but seemingly related in the films.
Edit pants.
Props and Materials
I want a kind of schizophrenic aesthetic, rooted in the past whilst still set in the present, representative of my main character (author). It is quite hard finding and being able to afford the materials working by myself, the record players and projectors are the key components, these are mostly borrowed. However to build up a more engaging environment, everything has to be carefully considered and other props and visual cues need to be added.
I am planning on a glass of whisky, a fat cigar (smoked), and some other signifiers to point towards the presence of a third character in the space. I also need an appropriate table on which to stage everything and a semi-circular screen on which to project. A cohesive aesthetic is always important but I really need it to drive the narratives involved.
**UPDATE**
I have a second turntable, it is a little more modern than I would lik e but it will still work I think, also been bootfairing and got my hands on a nice whiskey glass, ash tray and some fantastic old french cigarettes that will really fit well; hopefully pointing out some connections between the man, the strangers and the french woman. I still don't have a table, this is a real concern.
I have been really worrying about getting a cheap table that will look right with the piece and I have finally got my hands on one, me and Faysal had to carry it on the tube back from Earls Court but it will be great for what I need and can hopefully be sold on. Now I essentially have all the physical pieces to try and complete the project.
Construction
In this last week before the crit I've got all the materials and props so I can start mounting and finally putting together the the pieces. I haven't really been able to do any extensive testing until this point, the final product could well be determined by this period of experimentation. This is both exciting and terrifying.
Sound
I have finally recorded my sound piece to go with the visual experience, I really wanted to use an english speaking french girl to record some phone conversations with some classical music in different channels. I put together a short script:
Phone convo no.1:
Look, I’m sorry I left… I had to get out. I’m back in Europe now… I don’t think you’ll see me again. Don’t come looking.
Take care of yourself Henry *hangs up*
Phone convo no.2:
*all in French*
Bonjour? Bonjour? Hello(English)? Who is this?
Phone convo no.3:
Allo?
*Louder and away turned away from mic*
HEYEYEY, sei still, ich kann nichts hoeren (saaiii stiell ich kann nichts hoaeren)
*back to normal*
Hello? I’m sorry I can’t hear anything, you’ll have to call back
I am using this to hopefully lead the narrative away from the two strangers in the film loops, and reinforce the voyeuristic, eccentric and slightly obsessive nature of the main character, also filling in some back story while still remaining ambiguous and open to interpretation, the multiple languages used by the girl are supposed to insinuate the passing of time and relocation through space; a characteristic that she seems well accustomed to. For the music I have selected
Beethoven - Cello Sonata Op.5 No.2 - 1.Adagio - perhaps classical music is a bit obvious but it seemed fitting in nature and tone.
I have decided to use headphones to encourage the viewer to sit down in place of the character absent and hopefully stimulate more acute reflections on their relationship to the environment.
**UPDATE**
I found a French girl who, conveniently was half German. The recording sounds okay, she had problems with the third phone line, it sounded way too wooden so I have cut it off prematurely. I feel indifferent about the sound, I don't know if it works yet with the visuals but time will tell. I wanted it very dramatic and a bit over the top, I like to think that as someone sits in the chair watching the films with the projectors moving, the loops running, listening to the girls voice and the classical music, looking around at the table top, they will get a sense of what and who I have in mind.
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