bunch of changes to 3d model. firmware now has min and max speed setting.

README.md

@@ -24,7 +24,7 @@ Besides some common stuff like soldering wire and hotglue you need the following
 | IR Phototransistor | SFH 309 FA-5  | 2x    |
 | IR LED 3mm         |               | 2x    |
 | Resistor           | 1k Ohm        | 2x    |
-| Resistor           | 100 Ohm       | 1x    |
+| Resistor           | 50 Ohm        | 1x    |
 | Screw              | M2 10mm       | 4x    |
 | Screw              | M2.5 10mm     | 2x    |
 | Screw              | M3 16mm       | 8x    |
@@ -35,16 +35,16 @@ For the UV tracer option you also need the following parts.
 | Description | Type    | Count |
 | ----------- | ------- | ----- |
 | UV LED 3mm  |         | 2x    |
-| Resistor    | 100 Ohm | 1x    |
+| Resistor    | 50 Ohm  | 1x    |
 
 You have different options for powering the project.
 My first version for testing uses a pre-made AA battery holder.
 
-| Description    | Type   | Count |
-| -------------- | ------ | ----- |
-| AA Battery     |        | 3x    |
-| AA Bat. Holder |        | 1x    |
-| Screw (sunk)   | M3 6mm | 2x    |
+| Description    | Type      | Count |
+| -------------- | --------- | ----- |
+| AA Battery     |           | 3x    |
+| AA Bat. Holder |           | 1x    |
+| Screw (sunk)   | M3 <= 6mm | 2x    |
 
 The originally intended variant is a AAA battery holder printed into the model.
 I don't have the terminals for that yet so it is not finished.
@@ -55,11 +55,43 @@ I don't have the terminals for that yet so it is not finished.
 | Bat. Terminal Neg. |      | 3x    |
 | Bat. Terminal Pos. |      | 3x    |
 
-I'm also looking to design a LiPo version with charger included in the future.
+The AA and AAA options are not recommended due to their bulk and weight!
+They also have problems with disconnections on firing impulses.
+
+The preferred version uses a single LiPo cell and a charger PCB.
+
+| Description     | Type      | Count |
+| --------------- | --------- | ----- |
+| LiPo Battery    | 600mAh    | 1x    |
+| Resistor SMD    | 4k Ohm    | 1x    |
+| Charging Module | TP4056    | 1x    |
+| Screw           | M3 <= 6mm | 4x    |
+
+Be careful though!
+If you use the LiPo charger board, they normally come with the charge current set to 1A with a 1.2k Ohm resistor.
+You need to put in a higher valued resistor instead, otherwise the small battery will be charged with far too much current and the charger will get very hot.
+I recommend 4k Ohm or more.
+See [this page for more info](https://www.best-microcontroller-projects.com/tp4056.html#TP4056_Current_Programming_Resistor).
 
 [![Breadboard](electronics/OpenChrono_bb.png)](electronics/OpenChrono_bb.png)
 [![Schematics](electronics/OpenChrono_schem.png)](electronics/OpenChrono_schem.png)
 
+### Resistor Values
+
+The proper values for the IR LED current-limiting resistors, as well as the pull-up resistors for the phototransistors depend on the exact parts used.
+We want to run the transistor in "switch mode", as [described here](https://www.electronics-notes.com/articles/electronic_components/transistor/phototransistor-circuits-applications.php).
+So we need to keep the pull-up value low enough that it quickly is able to pull the IO back to high when the BB passes.
+At the same time we also want the LED resistor as low as possible, so the transistor properly switches the IO to low when the light is shining on it.
+
+I built a first prototype with potis instead of resistors on the outside of the case, to be able to adjust the values while measuring the outputs with an oscilloscope.
+Using this setup, I arrived at values of 100 Ohm for the LEDs at 4V supply voltage, and 1k Ohm for the phototransistors.
+When I later ran again with batteries that had a bit lower voltage, it no longer worked reliably.
+So for use with 3x AA(A) batteries, I went down to 50 Ohm for the LEDs.
+
+Also note the type of the phototransistor, "SFH 309 FA-5".
+The '5' at the end gives the current that passes when light shines on the sensor, in this case 1.6mA - 3.2mA.
+So if you use a different sensor you will probably have to adjust the resistor values!
+
 ## Software
 
 This project uses the [U8g2 library by olikraus](https://github.com/olikraus/u8g2) to draw to the I2C OLED display.

firmware/OpenChrono/OpenChrono.ino

@@ -26,8 +26,12 @@ static void calculate(uint16_t a, uint16_t b) {
         ticks = (uint16_t)tmp;
     }
 
-    tick_new_value(ticks);
-    lcd_new_value();
+    double speed = tick_to_metric(ticks);
+    if ((speed >= MIN_SPEED) && (speed <= MAX_SPEED)) {
+        // only register realistic velocities
+        tick_new_value(ticks);
+        lcd_new_value();
+    }
 }
 
 static void measure() {

firmware/OpenChrono/config.h

@@ -77,9 +77,18 @@
 
 // --------------------------------------
 
+// with a prescaler of 1, we can measure from 17m/s to 1120000m/s
+// with a prescaler of 8, we can measure from 2.14m/s to 140000m/s
+// with a prescaler of 64, we can measure from 0.27m/s to 17500m/s
+// see comment in ticks.cpp
+
 // allowed values: 1, 8, 64, 256, 1024
 #define TIMER_PRESCALER 64
 
+// values outside this range will be ignored
+#define MIN_SPEED 0.3 /* in m/s */
+#define MAX_SPEED 2000.0 /* in m/s */
+
 // --------------------------------------
 
 // placeholder data for debugging purposes

hardware/openchrono.scad

@@ -56,31 +56,40 @@ switch_screw_l = 10.0;
 switch_screw_d = 15.0;
 switch_off = 15;
 
-bat_h = bat_l + bat_spring_dist + 2 * bat_wall + 2 * bat_tab_d;
-
-$fn = 42;
-
-echo("sensor_distance", height - 2 * led_off);
-
-// https://dkprojects.net/openscad-threads/ 
-include <extern/threads.scad>
-
 // 1911
 thread_profile_1911 = [
     true, // type is_male
     12.0, // diameter
     1.0, // pitch
     0.0, // offset
-    9.0 // length
+    9.0, // length
+    0.0, // offset dia
+    9.1, // inner hole
+    true, // is cw thread
 ];
 
-// M14x1.0 female thread
-thread_profile_m14 = [
+// M14x1.0 CW female thread
+thread_profile_m14_cw = [
     false, // type is_male
     14.0, // diameter
     1.0, // pitch
     0.0, // offset
-    12.0 // length
+    12.0, // length
+    0.0, // offset dia
+    8.5, // inner hole
+    true, // is cw thread
+];
+
+// M14x1.0 CCW female thread
+thread_profile_m14_ccw = [
+    false, // type is_male
+    14.0, // diameter
+    1.0, // pitch
+    0.0, // offset
+    12.0, // length
+    0.0, // offset dia
+    8.5, // inner hole
+    false, // is cw thread
 ];
 
 // ASG / KWC Cobray Ingram M11 CO2 NBB 6mm
@@ -88,17 +97,30 @@ thread_profile_mac11 = [
     false, // type is_male
     16.5, // diameter
     1.5, // pitch
-    8.0, // offset
-    10.0 // length
+    9.0, // offset
+    10.0, // length
+    20.0, // offset dia
+    8.5, // inner hole
+    true, // is cw thread
 ];
 
-// debug / testing
-thread_profile_none = [ false, 0, 0, 0, 0 ];
+thread_profile_giant = [
+    false, // type is_male
+    34.0, // diameter
+    1.0, // pitch
+    0.0, // offset
+    10.0, // length
+    0.0, // offset dia
+    8.5, // inner hole
+    true, // is cw thread
+];
 
 thread_profiles = [
     thread_profile_1911,
-    thread_profile_m14,
-    thread_profile_mac11
+    thread_profile_m14_cw,
+    thread_profile_m14_ccw,
+    thread_profile_mac11,
+    thread_profile_giant
 ];
 
 thread_base = 5.0;
@@ -114,8 +136,6 @@ thread_adapter_screw_inset = 5;
 thread_adapter_in_body = 5;
 thread_adapter_h = body_screw_insert_height - thread_adapter_in_body;
 
-enable_gap_support = true;
-
 text1 = [
     "OpenChrono",
     "Liberation Sans:style=Bold",
@@ -131,14 +151,93 @@ text2 = [
     -60
 ];
 
+text3 = [
+    "OpenChrono",
+    "Liberation Sans:style=Bold",
+    12.0 - 4,
+    1.0,
+    70
+];
+text4 = [
+    "by xythobuz.de",
+    "Liberation Sans:style=Bold",
+    9.0 - 2,
+    1.0,
+    -70
+];
+
 texts_left = [ text1, text2 ];
+texts_lipo = [ text3, text4 ];
+
+lipo_lid_height = 65;
+lipo_lid_width = 80;
+lipo_lid_d = 3.0;
+lipo_lid_gap = 0.5;
+lipo_lid_gap_d = 0.2;
+
+lipo_lid_screw_d_small = 2.8;
+lipo_lid_screw_d_big = 3.3;
+lipo_lid_screw_area = 10;
+lipo_lid_screw_len = 10.0;
+lipo_lid_screw_off = 5.0;
+
+lipo_lid_compartment_d = 15.0;
+lipo_lid_compartment_w = lipo_lid_width - 2 * lipo_lid_screw_area - 5;
+
+lipo_pcb_w = 18.0;
+lipo_pcb_h = 29.0;
+lipo_pcb_d = 5.0;
+lipo_pcb_usb_w = 9.0;
+lipo_pcb_usb_h = 3.6;
+lipo_pcb_usb_off = 1.4;
+lipo_pcb_usb_wall = 1.5;
+lipo_pcb_led_dia = 2.0;
+lipo_pcb_led_dist = 5.0;
+lipo_pcb_led_off_x = 1.75;
+lipo_pcb_led_off_z = 7.0;
+
+lipo_w = 30.0;
+lipo_h = 43.0;
+lipo_d = 9.0;
 
+enable_gap_support = true;
 include_uv_leds = true;
 
+lipo_lid_angle = circum_angle(lipo_lid_width - lipo_lid_gap * 2, outer_dia);
+lipo_lid_angle_hole = circum_angle(lipo_lid_width, outer_dia);
+lipo_lid_angle_compartment = circum_angle(lipo_lid_compartment_w, outer_dia);
+
+bat_h = bat_l + bat_spring_dist + 2 * bat_wall + 2 * bat_tab_d;
+
+$fn = 42;
+
+echo("sensor_distance", height - 2 * led_off);
+
+if (include_uv_leds)
+echo("uv_led_distance", led_off / 2);
+
+// https://dkprojects.net/openscad-threads/
+include <extern/threads.scad>
+
 // how deep things on the outside have to be set in
 function circle_offset_deviation(off, dia) =
     dia * (1 - sin(acos(off * 2 / dia))) / 2;
 
+// circumference to angle
+function circum_angle(width, dia) = width / dia * 180 / 3.141;
+
+// from https://3dprinting.stackexchange.com/questions/10638/creating-pie-slice-in-openscad
+module pie_slice(r, a) {
+    intersection() {
+        circle(r = r);
+        
+        square(r);
+        
+        rotate(a - 90)
+        square(r);
+    }
+}
+
 module lcd_cutout() {
     difference() {
         cube([lcd_pcb_w, lcd_pcb_h, lcd_pcb_d + 10]);
@@ -150,8 +249,8 @@ module lcd_cutout() {
         
         // TODO hacky
         if (enable_gap_support)
-        translate([0, (lcd_pcb_w - 1) / 2, 0])
-        cube([lcd_pcb_w, 1, 9]);
+        translate([0, (lcd_pcb_w - 1) / 2, 1])
+        cube([lcd_pcb_w, 1, 8]);
     }
             
     for (x = [0, lcd_hole_off_x])
@@ -199,25 +298,29 @@ module thread(profile, thread_draw) {
         // male thread
         difference() {
             union() {
-                cylinder(d = outer_dia, h = thread_base);
-                metric_thread(profile[1], profile[2], profile[4] + thread_base, test=!thread_draw);
+                cylinder(d = outer_dia, h = thread_base + body_screw_depth);
+                
+                scale([1, profile[7] ? 1 : -1, 1])
+                metric_thread(profile[1], profile[2], profile[4] + thread_base + body_screw_depth, test=!thread_draw);
             }
             
             translate([0, 0, -1])
-            cylinder(d = inner_dia, h = profile[4] + thread_base + 2);
+            cylinder(d = profile[6], h = profile[4] + thread_base + body_screw_depth + 2);
         }
     } else {
         // female thread
         difference() {
-            cylinder(d = outer_dia, h = thread_base + profile[4] + profile[3]);
+            cylinder(d = outer_dia, h = thread_base + body_screw_depth + profile[4] + profile[3]);
             
-            metric_thread(profile[1], profile[2], profile[4] + thread_base + 1, true, test=!thread_draw);
+            translate([0, 0, -1])
+            scale([1, profile[7] ? 1 : -1, 1])
+            metric_thread(profile[1], profile[2], profile[4] + thread_base + body_screw_depth + 2, true, test=!thread_draw);
             
-            translate([0, 0, thread_base + profile[4]])
-            cylinder(d = profile[1] + 2, h = profile[3] + 1);
+            translate([0, 0, thread_base + body_screw_depth + profile[4]])
+            cylinder(d = profile[5], h = profile[3] + 1);
             
             translate([0, 0, -1])
-            cylinder(d = inner_dia, h = profile[4] + thread_base + profile[3] + 2);
+            cylinder(d = profile[6], h = profile[4] + thread_base + profile[3] + 2);
         } 
     }
 }
@@ -229,8 +332,30 @@ module thread_profile_adapter(profile, draw_profile) {
         for (r = [45, -45])
         for (r2 = [0, 180])
         rotate([0, 0, r + r2])
-        translate([0, (outer_dia - body_screw_insert_dia) / 2 - thread_adapter_screw_inset, -1])
-        cylinder(d = body_screw_dia, h = 100);
+        translate([0, (outer_dia - body_screw_insert_dia) / 2 - thread_adapter_screw_inset, 0]) {
+            translate([0, 0, -1])
+            cylinder(d = body_screw_dia, h = 50);
+            
+            translate([0, 0, thread_base])
+            cylinder(d = body_screw_head, h = 50);
+        }
+    }
+}
+
+module mac11_extender() {
+    difference() {
+        cylinder(d = outer_dia, h = 15);
+        
+        translate([0, 0, -1])
+        cylinder(d = 20, h = 15 + 2);
+        
+        for (r = [45, -45])
+        for (r2 = [0, 180])
+        rotate([0, 0, r + r2])
+        translate([0, (outer_dia - body_screw_insert_dia) / 2 - thread_adapter_screw_inset, 0]) {
+            translate([0, 0, -1])
+            cylinder(d = body_screw_dia, h = 50);
+        }
     }
 }
 
@@ -302,6 +427,13 @@ module half_body(right_side) {
             
             translate([-inner_dia / 2 - led_l - led_ridge_h - 5, 0, -10])
             cylinder(d = led_ridge_dia, h = led_ridge_h);
+            
+            if (include_uv_leds)
+            if (z < 0)
+            for (x = [0, 5])
+            translate([-inner_dia / 2 - led_l - led_ridge_h - x, 0, led_off / 2])
+            rotate([0, 90, 0])
+            cylinder(d = led_ridge_dia, h = led_ridge_h);
         }
         
         // TODO hacky led cable, led side
@@ -444,7 +576,7 @@ module right_half_aaa_bat() {
     }
 }
 
-module right_half_testing() {
+module right_halt_aa_bat() {
     difference() {
         right_half();
         
@@ -454,8 +586,8 @@ module right_half_testing() {
             
             // TODO hacky
             if (enable_gap_support)
-            translate([-0.5, 14, 20])
-            cube([1, 13, test_bat_h + 2]);
+            translate([-0.5, 14 + 1, 20])
+            cube([1, 12, test_bat_h + 2]);
         }
         
         for (x = [test_bat_off / 2, -test_bat_off / 2])
@@ -470,9 +602,118 @@ module right_half_testing() {
     }
 }
 
+module lipo_pcb_cutout() {
+    translate([-lipo_pcb_w / 2, 0, lipo_pcb_usb_wall])
+    cube([lipo_pcb_w, lipo_pcb_d, lipo_pcb_h]);
+    
+    translate([-lipo_pcb_usb_w / 2, lipo_pcb_usb_off, -1])
+    cube([lipo_pcb_usb_w, lipo_pcb_usb_h, lipo_pcb_usb_wall + 2]);
+    
+    for (z = [0, lipo_pcb_led_off_z])
+    translate([lipo_pcb_w / 2 - lipo_pcb_led_off_x, 0, lipo_pcb_usb_wall + lipo_pcb_led_off_z + z])
+    rotate([-90, 0, 0])
+    cylinder(d = lipo_pcb_led_dia, h = 42);
+}
+
+module lipo_lid() {
+    difference() {
+        rotate([0, 0, 90 - lipo_lid_angle / 2])
+        linear_extrude(lipo_lid_height - lipo_lid_gap * 2)
+        difference() {
+            pie_slice(outer_dia / 2, lipo_lid_angle);
+            pie_slice(outer_dia / 2 - lipo_lid_d + lipo_lid_gap_d, lipo_lid_angle);
+        }
+        
+        // screw holes
+        for (z = [0, lipo_lid_height - 2 * lipo_lid_screw_off])
+        for (r = [1, -1])
+        rotate([0, 0, r * (lipo_lid_angle / 2 - circum_angle(lipo_lid_screw_area / 2, outer_dia))])
+        translate([0, outer_dia / 2 + 1, lipo_lid_screw_off - lipo_lid_gap + z])
+        rotate([90, 0, 0])
+        cylinder(d = lipo_lid_screw_d_big, h = lipo_lid_d + 2);
+    }
+}
+
+module right_half_lipo() {
+    difference() {
+        right_half();
+        
+        // space for lid
+        translate([0, 0, (height - lipo_lid_height) / 2])
+        rotate([0, 0, 90 - lipo_lid_angle_hole / 2])
+        linear_extrude(lipo_lid_height)
+        difference() {
+            pie_slice(outer_dia / 2 + 1, lipo_lid_angle_hole);
+            pie_slice(outer_dia / 2 - lipo_lid_d, lipo_lid_angle_hole);
+        }
+        
+        // compartment behind lid
+        translate([0, 0, (height - lipo_lid_height) / 2])
+        rotate([0, 0, 90 - lipo_lid_angle_compartment / 2])
+        linear_extrude(lipo_lid_height)
+        difference() {
+            pie_slice(outer_dia / 2 - lipo_lid_d + 1, lipo_lid_angle_compartment);
+            pie_slice(outer_dia / 2 - lipo_lid_d - lipo_lid_compartment_d, lipo_lid_angle_compartment);
+        }
+        
+        // screw holes
+        for (z = [0, lipo_lid_height - 2 * lipo_lid_screw_off])
+        for (r = [1, -1])
+        rotate([0, 0, r * (lipo_lid_angle / 2 - circum_angle(lipo_lid_screw_area / 2, outer_dia))])
+        translate([0, outer_dia / 2, (height - lipo_lid_height) / 2 + lipo_lid_screw_off + z])
+        rotate([90, 0, 0])
+        cylinder(d = lipo_lid_screw_d_small, h = lipo_lid_d + lipo_lid_screw_len);
+        
+        // charging pcb
+        translate([0, outer_dia / 2 - 11, 0]) {
+            lipo_pcb_cutout();
+            
+            %translate([-(lipo_pcb_w - 1) / 2, 0.5, lipo_pcb_usb_wall])
+            cube([lipo_pcb_w - 1, lipo_pcb_d - 1, lipo_pcb_h + 1]);
+        }
+        
+        translate([-lipo_w / 2, outer_dia / 2 - lipo_lid_d - lipo_d - circle_offset_deviation(lipo_w / 2, outer_dia - (lipo_lid_d * 2)) - 1, 32]) {
+            cube([lipo_w, lipo_d + 20, lipo_h]);
+            
+            %cube([lipo_w, lipo_d, lipo_h]);
+        }
+        
+        // TODO hacky power cable
+        translate([15, -10, 27])
+        rotate([-90, 0, 15])
+        cylinder(d = 6.0, h = outer_dia);
+        
+        for (t = texts_lipo)
+        rotate([0, 0, -t[4]])
+        translate([0, outer_dia / 2 - t[3], (height + thread_adapter_h) / 2])
+        rotate([0, -90, -90])
+        linear_extrude(height = t[3] + 1)
+        text(t[0], size = t[2], font = t[1], halign = "center", valign="center");
+    }
+    
+    // TODO hacky
+    if (enable_gap_support) {
+        translate([-0.5, 10, 17.5])
+        cube([1, 17, lipo_lid_height + 1]);
+        
+        for (x = [-12, 11])
+        translate([x, 10, 31])
+        cube([1, 10, 45]);
+    }
+}
+
+module assembly_right_half_lipo() {
+    right_half_lipo();
+    
+    color("green")
+    translate([0, 0, (height - lipo_lid_height) / 2 + lipo_lid_gap])
+    lipo_lid();
+}
+
 module assembly_closed() {
     //right_half_aaa_bat();
-    right_half_testing();
+    //right_halt_aa_bat();
+    assembly_right_half_lipo();
     
     rotate([0, 0, 180])
     left_half();
@@ -483,13 +724,11 @@ module assembly_closed() {
 
 module assembly_opened(angle) {
     translate([-outer_dia / 2, 0, 0]) {
-        //rotate([0, 0, angle / 2])
-        //translate([outer_dia / 2, 0, 0])
-        //right_half_aaa_bat();
-        
         rotate([0, 0, angle / 2])
         translate([outer_dia / 2, 0, 0])
-        right_half_testing();
+        //right_half_aaa_bat();
+        //right_halt_aa_bat();
+        assembly_right_half_lipo();
         
         rotate([0, 0, -angle / 2])
         translate([outer_dia / 2, 0, 0])
@@ -498,20 +737,23 @@ module assembly_opened(angle) {
     }
 }
 
+module print_all_thread_adapters() {
+    for (p = [0 : len(thread_profiles) - 1])
+    translate([(p - floor(len(thread_profiles) / 2)) * (outer_dia + 5), -outer_dia / 2 - 5, 0])
+    thread_profile_adapter(thread_profiles[p], true);
+}
+
 module print(all_thread_adapters) {
     translate([outer_dia / 2 + 5, 0, 0])
     left_half();
     
-    //translate([-outer_dia / 2 - 5, 0, 0])
-    //right_half_aaa_bat(true);
-    
     translate([-outer_dia / 2 - 5, 0, 0])
-    right_half_testing();
+    //right_half_aaa_bat();
+    //right_halt_aa_bat();
+    right_half_lipo();
 
     if (all_thread_adapters)
-    for (p = [0 : len(thread_profiles) - 1])
-    translate([(p - floor(len(thread_profiles) / 2)) * (outer_dia + 5), -outer_dia / 2 - 5, 0])
-    thread_profile_adapter(thread_profiles[p], true);
+    print_all_thread_adapters();
 }
 
 //lcd_cutout();
@@ -519,8 +761,25 @@ module print(all_thread_adapters) {
 //left_half();
 //right_half();
 
+//right_half_aaa_bat();
+//right_halt_aa_bat();
+
+//right_half_lipo();
+//lipo_lid();
+//assembly_right_half_lipo();
+
 //assembly_closed();
 //assembly_opened(90);
 
 //print(true);
-print(false);
+//print(false);
+
+//print_all_thread_adapters();
+
+//thread_profile_adapter(thread_profile_1911, true);
+//thread_profile_adapter(thread_profile_m14_cw, true);
+//thread_profile_adapter(thread_profile_m14_ccw, true);
+//thread_profile_adapter(thread_profile_giant, true);
+
+thread_profile_adapter(thread_profile_mac11, true);
+//mac11_extender();