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Mar 30, 2019, 10:30 PM
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F3K timer open source hardware/software (GlideTime)

I have a few projects cooking in the evenings and weekends.. one of those is a custom stopwatch device to time F3K and other glider events. I was about 1/2 way done, and then got shown an Armsoar F3k timer, which is pretty much what I was going for. Buuuut... those don't exist, and aren't open source. I'm inspired by all the other work people have open-sourced around here (G_T's airfoils, the composite folks showing their videos, jfrickman's Taranis software, donations to me such as a throwing blade, etc..).

So here we go: an open source project to make an easy-to-use, domain-specific (F3K contests) timing device. This will morph over time as features are added or rules change (e.g... keeping 0.1 seconds resolution vs. 1. seconds).

I have the beginnings of the three major components to make this an easy-to-build device. Details in the thread responses below.
- software:
- circuit board (PCB) and bill of materials: Schematic and board layout
- case model for 3D printing <todo> (I only have the test-mule now, which won't work for the PCB)

The design is basically:
- Arduino pro mini 3.3v
- old 1s lipo or 3 AAA or similar
- Nokia 5110 LCD
- pushbuttons
- some other random components.

Software features:
- feedback to timer that launch has been started (e.g. flashing LCD for a second)
- eventual: custom displays and results for each task.

A prototype in action:
GlideTime UI v.0.2 (0 min 27 sec)
Last edited by dan1d; Apr 17, 2019 at 01:44 PM.
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Apr 05, 2019, 03:29 AM
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taurineman's Avatar
nice - is this an open-source sort of thing? i assume thats what you're implying? Is there a wiring diagram? a CAD model for the case? I would love to build one.
Apr 05, 2019, 11:48 PM
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I could make up a 3D model in Solidworks for you, if that would help. I don't have any special knowledge of 3D printing, but it's probably a good thing to learn about.

An audible beep when starting or stopping the timer is a good idea. Quality of the switch is very important. I've had a bunch of stopwatches that turned out to be unreliable because of lousy switches. Tactile feedback is good, too. The best buttons I've encountered may have been those on the old HP calculators. I have to admit I don't know which switches you can buy are best.

A fantasy feature would be a motion switch that starts the time when launching, for practice purposes. Ditto a simulated timer's voice.

As far as the software, I want something that makes my glider automatically stay up exactly as long as specified. ;-)
Apr 06, 2019, 12:29 AM
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Thread OP
Thanks for the feedback! I definitely see this as a community project. Besides the software, I'll link to my easyeda design for the PCB and schematic. I'll redo my 3d model of the case for this new board.

Just today I got my boards in and they work! Makes it super easy to build one since it's just soldering components versus making wires everywhere.
Apr 06, 2019, 12:40 AM
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taurineman's Avatar
Looks good!

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Apr 06, 2019, 12:49 AM
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links to schematic and PCB design

This was my first attempt at a PCB design... comments welcome. I was tempted to use KiCad, but this seemed so... easy.. to get started with.

Schematic and board layout

A few notes:
- The board has optional features and a few redundant components: there are two power switches and two power connectors to provide a few different options.
- When my AliExpress components arrive, I'll provide more detail in the bill of materials. Parts are relatively standard.
- I left the backlight disconnected from the LCD, but there's a resistor available if one wishes to use it. It may work with just a solder-bridge, but I wasn't sure what current the LEDs would pull.
- There are two pinouts for the Nokia 5110 LCD module. The most common one has its through-holes near the center of the board. I put the Sparkfun (and Adafruit, maybe) version at the top.

Now I need to figure out what to do with the other PCBs I have ;-) I was thinking of waiting for the other components to be sourced, and providing a kit.
Apr 07, 2019, 02:07 AM
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taurineman's Avatar
If ya feel like selling a pcb, I'll gladly take one!

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Apr 17, 2019, 01:48 PM
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Originally Posted by taurineman
If ya feel like selling a pcb, I'll gladly take one!
I fear shipping to NZ would not be economical... But you can probably get my board designed fabricated for $10 or so for 10! Just open the PCB design link I sent and clone it. There are links to a cheap manufacturer on easyeda.

I have several built but am refining the case and software. I added a bunch of features. See new video at the top
Apr 17, 2019, 02:25 PM
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Some prototypes...
Apr 17, 2019, 11:46 PM
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Bring one out to Poway. I wanna see this in action! Nice work.
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Apr 20, 2019, 05:59 PM
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The custom timer movement has started! I gave 2 out to fellow hardware hackers at today's Torrey pines gulls contest.

Except for fragile cases they seemed to fit the bill
Apr 20, 2019, 09:27 PM
No really, it doesn't have one
cgmoth's Avatar
These are looking great Dan! Gonna have to get one from you.

Apr 20, 2019, 10:13 PM
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You have done a great job. They work perfect. I really liked to window timer. Thank you again. I'm going to play with it a bit.
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Apr 21, 2019, 01:07 AM
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Thread OP
I have enough parts on hand to build a few more as-is. But it sounds like I better place some more component orders.
May 06, 2019, 10:23 PM
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Just my luck. Was printing a case for this to hold a round 650, and now the screen pooped out. It started going faint, and now, nothing. Dan, i need to buy one from you. Still working on the latch or screws to hold the top and bottom together. When i get it done I'll post the files. Printed the top and bottom in pla, and the buttons in tpu.
Latest blog entry: Cg scale

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