Delta 5 Race Timer Shield Case by techyg

Last crawled date: 3 years ago

Background
The Delta 5 Race Timer is an innovative, cost effective solution for keeping track of race laps when racing FPV (First Person View). The designer of the Delta 5 Race Timer is Scott Chin. The system is open source, and utilizes the video transmitter frequencies instead of traditional transponders. Video transmitters that work with this system can be purchased for as low as $10 (ex. Eachine VTX03). For more information about Delta 5 Race Timer, visit the following web site:
https://github.com/scottgchin/delta5_race_timer
The Delta 5 Race Timer system has native lap timing software, written in Python. It also integrates with LiveTime Scoring Engine, found here:
https://www.livetimescoring.com/
In the spirit of open source and community, I wanted to post my design. Before using my design, I encourage you to take a look at Scott's Github link above, or join the Facebook group:
https://www.facebook.com/groups/Delta5RaceTimer/
Scott has been working on a PCB that will greatly simplify the project (as of uploading this, it is still a WIP), though it won't fit in the same form factor as what I have here. His solution should save you a significant amount of time and effort, and will generally be more supported as others will be using it.
With that in mind, the design here gives you a lot of flexibility and I think it looks pretty cool!
Before you get started
This system is fantastic, and if you go with an 8 node set up, it should be doable for around $200, and of course less if you already have some of the components. I feel that this system is on par with the $600 Immersion LapRF! However, it is definitely a lot of work putting it together.
I have compared this system with some of the existing solutions (such as individual race trackers- both the Immersion Puck, and the TBS race tracker) on the market, and the timing is on par or better.
What to be aware of...
If you have never used a linux based / command line system before, you may have some challenges with the Raspberry Pi setup. Fortunately, the setup process for getting a raspberry pi up and running is pretty easy. You can also buy an SD Card pre-loaded with the image (though you still have to install the Race Timer software). I recommend joining the Facebook group if you need help.
Basic soldering skills, and soldering equipment are going to be needed. I assume that you're probably already in the RC hobby if you're reading this, so this shouldn't be a problem for most people.
Hardware
First, decide how many nodes you want to set up. One node can monitor one video frequency (in the 5.8 ghz range). The hardware currently supports up to 8 nodes. I started out with 4 and later added more. Please note: the software currently doesn't allow switching, and only monitors one channel per node. This means that the hardware is a bit more costly, but the lap times are going to be very accurate with the highest resolution possible.
All hardware required is listed on the Github link above, but I'll summarize it here and also add a few additional parts that I used. I purchased almost all of mine from Banggood. Prices listed are from there as of the time of writing this.
Each node requires an Arduino Nano. $8 each.
Each node also requires an RX5808. This is the video receiver. $10 each.
A Raspberry Pi 3 Model B - Pi 2's will NOT work (I believe due to timing/I2C communication). $35
1K resistors: Quantity 3. 100K resistor: Quantity 1. This is per each node. (Total of 24 1K resistors, 8 100K resistors if building 8 nodes). I recommend purchasing a resistor kit on eBay, or going straight to mouser.com and buying them individually. Cost: Around $10-$15
You will need one 5v 2.5A voltage regulator. This will be sufficient for powering all 8 nodes, which should draw around 2A of current (including the Rasp Pi). I recommend this one: https://www.pololu.com/product/2850 Cost: $12
I used a 4x6cm protoboard. This is required in order to fit in my case. Only $7 for a 24 pack. I used these:https://www.amazon.com/Uxcell-a14041800ux1143-Double-Protoboard-Prototyping/dp/B0166GCD42/
On Scott's PCB, he also sources the Arduino Nano's using a 3.3v regulator. This helps keep the heat of the RX5808's down. I don't use a 3.3v regulator but instead blow a fan on my electronics.
Other stuff:
You will need an SD card for the Rasp Pi. I recommend a 16GB one.
I used a 5000mah 3S battery to power my setup (via the 5v regulator). It lasts several hours, depending on how many nodes you have hooked up. $25
You will need to decide how you want to connect to it. Many people just use a really long ethernet cable (eg. 50-100ft). Wifi is also an option. Some people incorporate a small "travel hotspot" into their setup ($15-20). The raspberry Pi is capable of being it's own hotspot, but I wouldn't recommend it because the wifi range on the Pi is not very good.
Specific stuff for the case design:
I purchased this 80mm fan from Amazon. It works great with the design: https://www.amazon.com/MASSCOOL-80mm-Blue-Cooling-BLD-08025S1M/dp/B000S396YU
For the arduino nodes, you will need M2 screws, 6mm long. I use 3 per node (although there are holes for 4).
You will need M3 (quantity 4) screws for the case. I use longer screws on the bottom (15mm should work) and shorter screws on the top (10mm). The lengths aren't really important on these.
You will also need 2 36mm Power Distribution Boards. This helps make the wiring easier. I also used two short M3 screws and some lock nuts to hold in place. You could also glue them down if you wanted to.
You may want to use JST cables (as pictured) to allow for easy connect/disconnect. Same thing for the I2C connections- except perhaps Servo cables would be better. In my design, I used JST cables for the power, but just ran longer wire and directly soldered the I2C cables.
I used PETG filament. It's very sturdy and should survive drops.
You will need some hookup wire. I use 24 AWG gauge wire from Striveday on Amazon: https://www.amazon.com/StrivedayTM-Electric-electronic-Industries-electrics/dp/B01KQ0D3M0/
About the design
The case allows for up to 8 nodes. 4 are mounted on the bottom, and 4 on the top.
The 80mm fan cut out allows for rapid cooling.
I tried to get this case to be very compact, so there isn't a ton of room inside it.
About the wiring
I soldered the Arduino Nano straight to the protoboard.
Feel free to use my wiring layout/design. Use the comments if you have any questions.
On later nodes, I moved the Nano over one row to the left, because the first version blocked the bottom right screw hole.
I sourced the 5v power directly to the Nano via the 5v/GND pins. Please double check that you have the right pins before providing power, as there is no reverse current protection when powering with the pins. The RX5808's are also powered from these same pins. (Side note: the Nano is capable of powering up to 500ma over the 5V/GND pins, but the GPIO pins are designed for 50ma only).
Summary
The design is still a bit of a work in process, and I'll be updating it. I am currently on revision 3- you'll notice that some of the pictures have different color PETG, and those were some earlier prototype designs. If you have any comments/recommendations for improvements, please feel free to mention those in the comments.