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--- projects:sand_drawing:work_logs:improvements [2020/05/11 12:00] – tjhowse
+++ projects:sand_drawing:work_logs:improvements [2020/05/12 09:21] (current) – tjhowse
@@ Line 9: / Line 9: @@
 === Optoswitch mounts ===
-In order to write the software before finishing the complete enclosure I needed a way to mount the optoswitches roughly where they'd be in the final product. I need the optoswitches to detect the position of the arms. Stepper motors have no positional feedback of their own, so the usual system is to move them until you detect them in a certain position. For my current 3d printer that is detected with some mechanical lever switches. For my old printer I used little paper flags and optoswitches. An optoswitch is an infra-red LED and a receiver facing eachother. If something comes between them a signal is generated.
+In order to test the software before finishing the complete enclosure I needed a way to mount the optoswitches roughly where they'd be in the final product. I need the optoswitches to detect the position of the arms. Stepper motors have no positional feedback of their own, so the usual system is to move them until you detect them in a certain position. For my current 3d printer that is detected with some mechanical lever switches. For my old printer I used little paper flags and optoswitches. An optoswitch is an infra-red LED and a receiver facing eachother. If something comes between them a signal is generated.
 {{:projects:sand_drawing:work_logs:pasted:20200511-113321.png}}
@@ Line 35: / Line 35: @@
 New.
-I had noticed that arm1 could bend slightly about the joint because the joint was in shear. It could twist slightly because it was the compression from the bolts causing friction between the touching faces. The tension in the belt could overwhelm this fiction and the two faces would slide against eachother.
+I had noticed that arm1 could bend slightly about the joint because the joint was in shear. It could twist slightly because it was the compression from the bolts causing friction between the touching faces. The tension in the belt could overwhelm this friction and the two faces would slide against each-other.
 The new arrangement puts the bolts into tension and there is no force acting to shear the joint.