I’ve been in heavy development on the Twin Dolphin Speed Climbing timing system. In the last article I discussed how the sensors were designed, made and assembled.
Since then I’ve been mainly focused on the timing electronics including the master controller and the display.
The master controller is a circuit board I designed which monitors the state of both lanes’ hands and feet sensors. It listens for the start signal from the remote, starts the clock, does false-start detection, and ultimately determines the stop time for each climber. Immediately after the race is finished it wirelessly sends the official times to the display clock to display.
The master controller board looks like this. Each sensor in the system, one hand sensor for each lane and one foot sensor for each lane, plugs into this board through an RJ45 jack. This board will be in a custom enclosure I am designing so it will be protected.
This circuit board is one I designed which has a very fast microcontroller on it (a 64MHz dsPIC33FJ ), and maintains bi-directional communication with each sensor as well as wireless communication to both the remote starter and the display clock for the audience.
With this board and the firmware I can control the on/off state of the laser in every sensor, the RGB color of the light bar embedded in each sensor, maintain an extremely accurate time-base, and talk to the LED display. For the first time it is possible to test the hand sensors from the ground and have the system do a self-test.
All the code written for the speed climbing timing system, the master controller and display controller, is written in C using the MikroC compiler.
Similar to the design process for the sensors, I designed the display enclosure in CAD, cut the parts on the CNC, including the acrylic lens for the display.
This is a screen shot of the display. You can see it’s made up of various layers and constructed like a sandwich. (Each layer has 8 bolt holes – this screen shot was taken when there were 6). The holes in each layer line up so the entire sandwich is bolted together with 1/4″ bolts making for a very strong display case.
This is the brake-light red acrylic lens being cut on the CNC router. It still has its protective adhesive backing paper on it during the cutting, but instead of saw-dust, you can see all the plastic shavings getting blow around as it’s cutting the profile.
The display controller is another printed circuit board I designed which is similar to the master controller (same microcontroller) but is focused mainly on communication with the master, time keeping for the audience, and the driving of the large LED display shown above. The circuit board below is the display controller board and the first board I’ve developed since we finalized the Twin Dolphin logo, so of course, the new logo had to go on the silkscreen.
The board is installed along side the large LED and communicates with the LED board via the rainbow ribbon cable on the right side in the photo above and below.
The display controller board is parasitically powered from the LED display board. The LED display board uses a Max7219 so the display controller controls the time shown on the LED using the Max7219 SPI protocol.
After the firmware is flashed into the display controller and display is tested, the top two sandwich layers can go onto the display. The acrylic lens and the bezel over the front get bolted on:
The back of the display has some heavy duty mounting rings that can be used to hang or tilt the display towards the audience:
Of course after it’s all buttoned up again, it’s retested. This is a full timing system on my office desk going through integration and system testing. You can see the two hand sensors on the top of the desk (2 green light bars) and the two foot sensors on the floor (2 red light bars). This configuration makes it easy for me to run it through its paces and if there are any issues with hardware or firmware, debug and retest in a tight loop.
Well, that’s all the time I have for an update, but thought you might be interested in seeing some of the other dimensions of the speed climbing timing system coming together.
I mentioned earlier that I’m designing a custom enclosure for the master controller and remote. Here’s a quick rendering of how the master controller enclosure may look:
There’s a lot more to talk about here with the design and build of the enclosure, but want to devote the next article to that and a new tool in my arsenal, a 3D printer.
Landon Cox, June – 2014
