I’m publishing 2 versions of external sensors. the first version is easier for the FOXLAP DIY version and the second version is the best option for the dedicated board device.
The first version is called “external sensor box” (and i’m starting with this version). the second version will be called “internal sensors” (even if obviously the probes are not inside the box, but i just had to give them a name)
Why the “external sensor box” is better for the DIY device? because there are already so much cables and little boards inside the device that it became tricky to add even a little board inside. i made it and it works but there is no added value to make the device more complicated inside. the “external sensor box” does the job as expected and it is easier to assemble.
1- External sensor box
This tutorial will explain how to build the external sensor box to monitor RPM and water temperature. This sensor sensor box will be connected to the FoxLAP device (compatible with both DIY version and dedicted board) via a 4wires cable with an M8 connector.
1.1 – Print the model
- STL files were created using Blender.
- 3D Printer: Creality CR10s PRO.
- Slicer: I used Cura to slice the 3D models
- 3D filament: i used the 1.75mm ZIRO Filament PLA with carbon fiber. Amazon link: https://www.amazon.com/dp/B01IICFS4Y/
- Print settings: 0.4mm nozzle, Standard quality (0.2mm), 40% infill, Support (zig zag support)
- Print Speed: Usually I set the speed to 60% of the maximum speed the printer can achieve. Because I saw that the more I increase the speed, the more faulty prints I get.
The zip contains the box and the RPM clipper.
1.2 – What you will need
FoxLAP – External sensor pack
FoxLAP – External sensor pack. Everything needed to Monitor RPM and water temperature. The PCB will be connected to the FoxLAP device (compatible with both DIY version and dedicated board version) via a 4wires cable with an M8 connector. In this picture you see the content of the external sensor pack. Probes and connectors were custom made to be mounted on goKart engines such as Rotax (J125, Max, Max Evo) More info
Out of stock
In this picture you see the content of the external sensor pack. I made a package including what you will need. probes and connectors were custom made to be mounted on karting engines such as the Rotax. It includes:
- 1 cable (4wires) with a 4 pin connector (2meters, you can adapt length to your need)
- 1 M8 connector (will be mounted at the bottom of the FoxLAP device)
- 1 PCB
- 1 RPM cable
- 1 water temperature probe with his water proof connector
- 1 Clip-On Ferrite Ring Noise Suppressor
- 4 M3 9mm screws
External Sensor pack available here: https://foxlap.com/tutorials/product/foxlap-external-sensor-pack/
or contact me here, I have also few dedicated boards available
1.3 – Assembly guide
Put the PCB inside the printed box. H2 on the side of the box where there is only 1 hole
Adapt the length of the main cable (the one with the 4-pin connector) to what you need on your gokart (or bike or whatever). Usually a good length is between 140cm and 150cm. Keep in mind that you will have to install it on your gokart/bike. So please take a look at the setup guide before
Insert your 4-pin cable inside the hole and solder the 4 pins. Keep the color rules as mentionned here because this cable must be connected to the foxlap device (and we don’t want any nasty surprises with incorrect wiring)
blue ->+3V
brown ->GND
black ->RPM
white ->TEMP
You will need to solder the wires inside the box so be carefull. I use solder paste to make this task easier (I’m just sharing with you what is easiest for me – but maybe you have your own tips and habits)
Solder the RPM cable to the COIL pin and the 2 wires water temperature cable to “D” and “3V” pin (no matter wich cable goes to D or 3V)
You must have now something like that:
Before closing the sensor box, make sure it works by pluging it to your foxlap device (if you made the version able to host external sensors – otherwise go to the foxlap DIY tutorial in order to get it done)
Once your test is OK, put hot glue (or isolation paste) inside the box to close the cables holes to prevent water to enter.
And then finally close the box with the 4 M3 screws
IMPORTANT in case of use with the DIY version
Particularly in case of use with th DIY version, you must add a Clip-On Ferrite Ring Noise Suppressor on the 4pins cable. you can find it here https://www.aliexpress.com/item/1005007138649892.html for example if you don’t already have it.
And it’s done. now we have to install it on the gokart
2 – Setup
It’s not something difficult, if you are at this stage now, the hardest part has been done.
Install the water temperature probe on your engine.
prepare Zip ties to install the box
This is where i install the sensor box. So it’s easy to access to remove the water temperature probe when you change the engine. Add other zip ties to install the cables properly
clip the rpm cable
And now it’s time to see it in action. (no error for the water temperature sensor, it was close to 0°c when i recorded this video )