The building instructions are still in progress. Use at your own risk.
Requirements
Soldering experience**: Soldering the components together is challenging in places. You should therefore have soldering experience or get someone with soldering experience to help you.
You will need the parts from the [shopping list](/docs/shopping list/) and the necessary tools. You can check parts and tools list to see if you have everything you need. If you decide to design your own housing solution, you are of course welcome to do so. You may save a few laser cut/3D printed parts.
Time required
Experience from the first building workshops shows that you should take between 2 and 3 hours, depending on your soldering skills.
Dealing with the instructions
Read through the complete instructions once and check whether you can follow all the steps. This will also help you to better understand the individual steps.
Photos and description texts complement each other. Read through the instructions in full for each step and take a close look at all the photos for each step. Then you shouldn’t have any problems.
1 - Shopping list
Here you get the single parts
Preliminary remarks
This shopping list is a rough guide. If you order all the parts, you can follow the instructions in the next steps in any case. However, there are a few freedoms and potential savings:
Ordering:
Our shopping list is optimized for as few individual orders as possible. It may be that you can obtain smaller packaging units and/or lower prices from other suppliers. It might be worth doing some research here.
Housing:
You are of course free to design your own housing. It should just be moisture-proof and not reflect the radar waves.
This way you can save the laser-cut parts and the housing from the shopping list. If you solder the electronics together as we did, we still recommend the 3D-printed bracket.
Charge controller:
If you want to build more than one sensor, not every sensor needs to be equipped with a charge controller. You can of course use one charge controller to charge several batteries.
How to connect the individual electronic parts to form a functioning sensor
Now it’s getting electronic. You should be able to solder for the following work. We will now explain the rest in as much detail as possible.
Soldering all the components together can be challenging. If you don’t have much experience in soldering, look for help with the soldering work
2.2.1 - Teensy developer board
All preparation steps for the Teensy developer board
What you need
Tool
Cutter knife
Soldering iron + solder
Micro USB cable + 5V power supply/USB port of the laptop
Parts
Teensy developer board
Button cell holder
Shrink tubing (1cm)
This is how it works
Function test
The red LED should flash when powered via USB.
The Teensy should basically work before you start with the customizations. Connect the Teensy developer board to a power source via USB. The red indicator light should flash. Now disconnect the USB cable again.
Disconnect contact for USB power supply
The connection between the two rectangular contacts (circled in red) must be removed. Circle 1 and 2 show how.
The Teensy developer board is to be powered by a battery pack for this project. To ensure that it is not inadvertently supplied with power via battery pack and USB, we must first deactivate the power supply via USB.
In the photo, two square contacts are circled in red. The two traces are connected by a small trace (see arrow in circle 1). You have to scrape this away with the cutter knife until it looks something like in circle 2.
To check, connect the Teensy to a power source via USB again. The red LED from the first step should no longer flash/light up.
You can only continue if the Teensy’s red indicator light no longer flashes/lights up. Otherwise you will have to rework.
Prepare the button cell holder
Button cell holder with shrink tubing over the connection cables
A button cell also supplies the Teensy with power when it is not connected to the battery. This means it does not lose its time and date settings while you are charging the battery.
Before you can solder the button cell holder to the Teensy, a small piece of shrink tubing (1 cm) must be pulled over both cables (but not yet heated). This will provide strain relief later.
Please only insert the button cell when you are asked to do so in the instructions. Otherwise there is a risk of short circuits during soldering.
Solder on the button cell holder
Soldered button cell holder
The red cable must be soldered to pin 32, the black cable to pin 28. The pin designations can be found on the back of the Teensy
It is important that the cables on the underside of the board do not protrude. The SD card slot from the audio board will be located here later. This must not come into contact with the solder joints.
Preparation of the Audioshield for assembly with the developer board
What you need
Tool
Side cutter
Pointed pliers
Soldering iron + solder
Soldering pliers
Parts
Teensy developer board
Audio shield
2-core cable (4cm)
40-pin header
Battery socket
Battery pack (only for checking the correct polarity when soldering)
How it works
Shorten the pin header
Shorten the pin header to the length of the audio shield
The 40-pin strip is too long for the audio shield. Simply insert it flush on one side onto the row of holes in the audio shield and cut off the excess with the side cutter.
Do the same for the opposite side. You should now have two strips of the same length (14 pins) and a shorter remaining piece.
The remaining piece is no longer needed. It is best to put it aside so that you don’t use it by mistake.
Solder the pin headers
The short ends of the shortened pin headers are soldered to the audio shield.
Now insert your two pin headers of the same length into the audio shield with the short side from above (side with jack connection and Micor SD card slot) and solder the headers to the back of the audio shield pin by pin.
Set up Teensy and customize pins
Clip off the pins (cyan) or bend them (red).
Now place the Teensy on the long pins. The USB socket points upwards and in the same direction as the audio shield's jack connection.
Use needle-nose pliers () to bend the pins on 5V and GND diagonally forwards as shown in the photo.
In order to be able to solder the voltage transformer properly later on, use the side cutter () to cut off pins 21, 22, 23.
Now solder all the pins to connect the two boards.
Prepare the socket for the power supply
Solder the socket cable together
In the picture you can see the two-core cable (4 cm) framed in cyan and the connection socket. The connection socket still contains a plug (with cable) that was included in the scope of delivery. This can be a help when soldering. However, you will no longer need the plug and cable in the following steps.
Cut the two-core cable (4 cm) a little on both sides and strip all ends. (Already done in the photo)
Now solder the cable to the socket so that the polarity matches the plug of the battery pack.
Caution: Some socket/plug sets have the polarity reversed. Always compare whether the plug has the same polarity as the battery pack and only then solder the socket to the cable accordingly.
Solder the socket with strain relief
Solder the socket cable together
Now route the cable of the button cell holder (already soldered to the Teensy) over the Teensy in the direction of the USB socket. Then feed the black cable of the battery pack socket from the previous step (coming from the button cell) through the shrink tubing.
Solder the black cable to the bent GND pin and the red cable to the likewise bent 5V pin.
In order to relieve the soldering points for the cables of the button cell holder against tension, all cables are "fixed" in the shrink tubing by heating them. To do this, push the cables of the button cell holder back slightly in the direction of their soldering points so that there is no longer any tension on these cables. Now carefully heat the shrink tubing with a heat gun or lighter.
You must install a voltage converter for the power supply of the radar module. You also need to prepare connections for data exchange between the components.
What you need
Tool
Spitzzange
Soldering iron + solder
Parts
Teensy developer board + audio shield from previous step
Voltage converter
Header 6-pin
Header 4-pin
Cable (approx. 4 cm)
How it works
Connect voltage transformer and Teensy
Voltage transformer, soldered to GND and 3.3V of the Teensy
Not in the photo: Place the voltage transformer in front of you with the label facing up and the feet pointing towards you. Now bend the two left feet upwards by 90° as close to the voltage transformer as possible.
See photo: Now place the voltage transformer on the Teensy with the label facing downwards. Make sure that the bent feet are on the left of the two single pins that protrude from the 3.3V contact and GND contact (to the right).
Now you can solder both contact points.
Preparing the plug connection (part 1: header 6-pin)
Pin 1 pulled out
Pin 5 and 6: First bend 90° backwards
Second bend down
Both pins soldered to the line-in of the audio shield
Click through the bending tabs (1.-4.) to see detailed photos of the individual steps.
Pull pin 1 (far left) out of the connector. It is no longer needed.
First bend pins 5 and 6 (far right) backwards by 90°. Then bend them downwards by approx. 75 degrees with a gap of approx. 4 mm. Both pins must reach the line-in contacts of the audio shield and be soldered there.
Soldered header 6-pin
The header 6-pin must fit on the end of the radar module. It can help if you attach the radar module to the audio shield to bend the pins. The necessary steps are explained from here in the "Assembly" chapter.
Bend enable (pin 2) to pin 17 of the Teensy and solder together (just fits).
Connect Gnd (pin 4) and Vcc (pin 3) diagonally to the output of the voltage converter (see photo). You may have to bridge this with solder or a short wire. The photo at the bottom of the page shows another top view that may be helpful.
Make sure there are no cross connections. If necessary, bend the wires slightly apart.
Preparing the plug connection (part 2: header 4-pin)
Prepared header 4-pin.
You must solder one end of the cable (4cm) to one of the inner contacts of the header 4-pin.
Final result
Final result after executing all steps
Solder the other end of the cable coming from the header 4-pin to GND (lineout or mic) of the audio shield.
In the end, everything should look like the photo.
After you have finished the electronics, the housing must be prepared and everything assembled.
What you need
Tool
Screwdriver
Tap cutter Mx
Cutter knife
Parts
Housing
Battery pack
Lasercut feet
Lasercut adapter plate
Radar bracket
Radar module
MicroSD card
Everything assembled so far
5x M3x5mm screws
4x M3x14mm cylinder head screws
How it works
Mount the adapter plate
All four holes must be fitted with an M3 internal thread
For mounting on street lamps or the tubes of street signs, we need an intermediate piece between the box and the post.
Use the M3 tap to cut an internal thread in each of the four holes in the adapter plate from the laser cutter
Use an Allen key to insert all four cylinder head screws from the inside through the opening and the spacer washer and screw them into the adapter plate.
Now take the 4 M3x14mm cylinder head screws, insert them through the recesses at the corners of the housing (from the inside to the outside) and screw them to the adapter plate.
Attach base plate
Base plate with Velcro tape for the battery
First insert the Velcro tape into the middle opening with the soft side facing upwards and guide it towards the cut-out
.
Then place the base plate in the housing with the loose Velcro ends facing upwards and screw tight with M3x5mm screws. The orientation of the plate within the housing does not matter.
Attach battery
Battery pack in the housing
Attach battery to base plate with Velcro fastener.
Insert radar module into frame
Front
Back
Carefully insert the radar module into the 3D print holder so that the 4 pins protrude through the gap in the holder and the 6 pins on the opposite side protrude through the large opening. The module should be firmly inserted into the 3D printed part at the end.
Attach and screw on Teensy/Audioshield
Front
When attaching the Teensy&Audoshield to the pins of the radar module, you just have to make sure that the holes for the screws in the audio shield match those of the 3D print holder.
Then you can connect the 6-pin connector first and then
Plug in the 4-pin connector so that the cable is soldered to the second pin (as seen from the jack connection).
Then attach the audio shield to the bracket with 3 M3x5mm screws.
Screw the radar module frame to the adapter plates
Screwed-on feet
Now you can screw the feet from the laser cutter to the 3D print holder using one M3x5mm screw each. Do not screw them on too tightly so that you can still move the module.
The longer of the two long edges points towards the wide end of the 3D print holder, while the overhang on the short edge points away from the radar module.
The feet are only in the base plate for the photo. You do not need the base plate here, it can remain screwed into the housing.
Insert micro SD card
MicroSD card in the slot of the audio shield
The slot for the MicroSD card is now located between the Teensy and the Audioshield. The micro SD card must be carefully pushed into the Audioshield slot with the contacts facing downwards as far as they will go.
Button cell holder
Button cell holder with button cell
Now insert the button cell into the button cell holder. The positive pole of the button cell must point towards the cover. Make sure that the switch on the housing of the button cell holder is set to "ON" and only switch it to "Off" if you have to change the button cell anyway.
s
Electronics in the housing
Front
Insert the radar unit next to the battery in the slots provided. The slot for the MicroSD card faces away from the battery. The radar unit is held in place by the screwed-on cover, so you can easily access the MicroSD card at any time.
Space is somewhat limited here. But with a little dexterity, you can insert the radar unit without it getting jammed. If necessary, loosen the battery slightly to allow more play.
Seal the housing cover
Shortening the rubber seal.
Insert the rubber seal into the groove once all the way around and cut off the excess with a cutter knife.
This step is important to prevent moisture from penetrating the housing.
Congratulations! The hardware part is complete! Before you can screw the cover onto the housing (supplied or M4x20mm security screws), you still need to flash the software onto the Teensy developer board
The manufacturer of the Teensy provides the software (Teensy loader) for flashing for Linux, Windows and Mac on its website (see above). You can get the necessary .hex file from our repository (also linked above). Now you can connect the sensor to your PC/laptop via micro USB cable, start the Teensy loader and flash the .hex file. Simply follow the instructions on the manufacturer’s website.
When flashing, the current time is also transmitted to the Teensy. This is important so that we can later assign the data to the date and time of day. If the power supply via the button cell is interrupted at any time (defect or replacement of the battery), simply reflash the .hex file before the next measurement.
The Teensy starts working immediately after installing the software. This means that there may already be .csv and .bin files on the memory card. It is best to disconnect the sensor unit from the battery pack now and delete these files from the SD card. You should not accidentally load this data into the portal later.
Flashing with Arduino IDE
If you are familiar with the Arduino IDE, you are of course also free to clone our repository and flash the Teensy yourself.
Possibly more Velcro straps (for thicker lantern masts)
(Safety) cable ties
This is how it works
Before and after hanging up
As soon as the sensor is connected to the battery pack, it starts recording. If possible, connect the sensor on site first and disconnect it immediately after the measurement so that no unusable data is recorded during transportation to the installation site. We are working on a solution that allows you to switch the sensor on and off from the outside.
Find out beforehand or on site which speed limit currently applies and whether there are any other special features (roadworks, etc.). You must specify this when uploading.
Generate usable data
The sensor should be mounted at chest height, at a 10° angle to the road and pointing away from intersections.
The quality of the data depends heavily on the orientation of the sensor. The following things must be observed:
The sensor must be mounted as close to the roadway as possible and at approximately chest height. It should also point towards the road at an angle of about 10°. The poles of traffic signs are best suited for this (the Velcro strips described in the assembly instructions are also sufficient for this diameter). However, the sensor should never cover a traffic sign
The alignment should always point away from intersections or driveways to avoid incorrect measurements.
The sensor detects vehicles in both directions. This works best when there are no traffic islands or other obstacles in the middle of the road.
Only a straight stretch of road provides reliable measurement results. Bends should be avoided.
Even if the sensor detects both directions of travel, you must remember the direction in which the sensor is pointing and specify it later when uploading.
Anti-theft device
The adapter plate has a recess in the middle to prevent theft. Here you can either thread through a normal cable tie (not a major obstacle) or the Hip Lok Z security tape (linked in the shopping list) for more theft protection.
Depending on the local conditions, it may of course help to position the sensor as inconspicuously as possible (e.g. on the back of street signs). However, make sure that good measurements (see above) are still possible.
Take photos
Photos of the suspended sensor help us to get an impression of the conditions at the location. They also allow comparable measurements to be taken at different times, as the sensor can be hung up in exactly the same way. The photos can later be uploaded to the platform together with the data for the respective location.
**The photos should be taken in such a way that the environment around the installation site can be recognized. Care must also be taken to ensure that no personal data (recognizable road users, license plates) is recorded or made unrecognizable before uploading.
With the magnetic switch you can start/stop the sensor without having to unscrew the housing every time.
Preliminary remark
The magnetic switch allows you to start and stop the sensor from the outside. We use a reed contact (normally closed contact) for this purpose, which we attach to the housing wall from the inside. If a magnet is now held in the right place from the outside, the circuit is interrupted. So if you take the magnet with you after installation, the sensor starts to measure. When you come back to dismantle the sensor, push the magnet back on and stop the measurement.
You are completely free to decide where you install the reed contact in your circuit and where it is positioned on the housing. The main thing is that the power supply to the Teensy can be interrupted by the contact.
The 3D printed parts linked below are aligned to the reed contact also linked and kept as small as possible. If you want to make changes to the parts, you can use this FreeCad project file.
It depends on the correct alignment of the magnet to the reed contact. If you use other contacts, you may have to construct your own magnet holder, depending on how it works.
You need to produce these three parts using a 3D printer. They are designed so that both the reed contact and the magnet rest directly on the housing wall. If you want to use your own designs, you must also take this into account so that the reed contact is triggered.
Gluing on the holder
All required 3D printed parts
All required 3D print parts
first glue the reed contact holder into the housing. Make sure that the small triangle points towards the housing and that the tip of the triangle is not positioned higher than the indentation on the edge of the housing where the cover will later click into place.
Now glue the magnet holder on the outside so that the triangle is aligned and positioned at the same height (eye measurement is sufficient) as the triangle on the reed contact holder on the inside. It is also important that the narrow part of the bevel points towards the housing. Otherwise it will be impossible to slide the magnet on later.
Wiring of the reed contact
Pluggable integration variant makes the use of the magnetic switch optional.
You can freely choose where to install the reed contact in the circuit. You can solder it permanently or make it pluggable with an extra plug and socket as an optional part, as shown here.
As soon as the wiring is complete, the reed contact must be inserted into the holder with the square protrusion pointing towards the inside of the housing. Make sure that it really is fully seated against the housing wall.
Test the correct orientation of the magnet
Magnet test plugged in to test orientation
Magnet glued into the magnet holder.
The reed contact will only reliably interrupt the circuit if the magnet is applied in the correct orientation. It therefore depends on which side of the magnet points to the left and which to the right. To find out the correct orientation, insert the magnet without its holder (3rd 3D printed part) into the holder and connect the rest of the circuit. If the sensor remains off (no LEDs light up/flash), you have already found the correct orientation. Otherwise, turn the magnet around and repeat the test. Alternatively, you can of course also measure for continuity with a multimeter.
Now that you know the correct orientation, you can glue the magnet into the holder. The holder is designed so that it can only be slid open in one direction (small locking lugs at one end). Glue the magnet into the holder so that it is correctly oriented when you slide it on. Make sure you press the magnet fully into the holder so that the distances are correct afterwards.
The final “off” position
This is what the off-position looks like
When everything is glued and plugged together, you can connect the circuit completely. As long as the magnet is in place, no current will flow. Only when you remove the magnet holder/magnet does the measurement begin.
Side cutter
Screwdriver
