The ubiquitous parking pilot aka yellow/black plastic thingy in the parking lot - Page 1
Forum section: electronics / general

author: Stefan .
author_rank: Contributor
timestamp: March 15, 2023, 07:53:25 pm
content: Sometimes things happen.So did a few days ago when I drove to the usual supermarket with my 'refusing to die japanese car'. Due to sunny weather I opened the sunroof.I parked a a free space in the parking lot and headed into the market.Coming back and entering the car I saw that some fellow human had put something through the open roof into the car. A Yellow and black plastic thingy.Looking very familiar because usually these things are glued to every parking place in the lot.At least in germany there is a flood of systems to control private owned parking lots and to ensure people only park there during their shopping. There are camera based systems and sensor based systems or a combination of both.One of the companies providing this 'service' is 'https://smart-city-system.com/en/outdoor-sensor/' with their 'parking pilot' and the yellow/black bricks.Eventually the fellow human throwing this thing into my car did do me a favor: I always wanted to know whats inside these bricks glued to the concrete.Back home I inspected the thing. Nothing too scary about it.The yellow plastic ring is ramp shaped to provide smoothness while driving over it and make it snow plow rejectend.In the middle, the black box is where the magic happens; quite easy to extract from the yellow frame; no special tools needed. Just pry at the right place and off it goes.Nothing special on the backside, just a sticker showing the sensor ID, manufacturer and CE. Remarkable: no text or logos showing any certificates regarding radio or danger due to batteries.The black case is easy to open and hardly glued, mostly relying to the friction between the case and the lid.Greeted by a big battery, a lot of nylon reinforced plastic (the sensor shall withstand 2.5ton of car weight) and a circuit bord embossed in this gooey transparent silicon stuff I was eager to find out more.The battery is encased in its own compartment and halfway surrounded by a thick 3mm aluminium shell. More about that later.Removing the battery and flipping it over reveals ahttps://www.fansobattery.com/3V 9500mAh Li-MnO2 battery. which btw. is still fully charged.Here the aluminium shell can be seen.Something not very obvious: the two 'feet' on the left side of the aluminium are screwed to mounting blocks on the pcb and electrically connected to the circuit, at least one of them. Any clues? Yes? Correct.After removing the pcb and cleaning it from the gooey stuff I was ready for further inspection.Not much to see here. Battery connections, some test points, a lot of stitches. LED and RFID are designated. None or the obviously present.Time to flip around:Not a lot to see. Very tiny components, lots of resistors, some capacitors, 5 ICStarting with the brain:https://www.st.com/en/microcontrollers-microprocessors/stm32l071kz.htmlST Micro STM32L07KZ ARM Core m0+ a the usual suspect today. Some 192kb ROM, some RAM and eeprom, I2C and SPI, some more I/O. Up to 32MHz and ultra low power design.Have a look at the datasheet.For the radio:Semtech SX 1261 LoRa Modem chip.https://www.semtech.com/products/wireless-rf/lora-connect/sx1261This is used to communicate to the base station somewhere around the parking lot, mounted to the building wall or a lamp post. The base station itself connects to a (cloud) server somewhere and sends the sensor date to there in order to be processed and displayed to the appropriate app.Combined with the PE4259 RF-Switchhttps://www.psemi.com/pdf/datasheets/pe4259ds.pdfin its SOT-23 package this makes up for the RF frontend.This RF switch is needed because the LoRa modem is not able to send and receive simultaneously. Therefore this RF Switch is needed to connect the antenna either to the RFIN or RFOUT of the LoRa modemSpeaking of antenna: yes, the aluminium shell is the antenna for this device; its connected via the screw terminal to the pcb and via the switch to the modem chip.Clever design as the aluminium shell also provides a protective shield for the powerful battery.Two more:This is a STM RFID/NFC Tag IChttps://www.st.com/en/nfc/st25dv04k.htmlThe chip provides some memory accessible via RFID or I2C.However, there is no NFC antenna connected although the solder points are present. IMHO this was designed as a feature to read or write some parameters to the memory after the device has been assembled or glued to the parking lot. This feature is no longer used or needed but some clever programmer decided to use the available memory for other stuff so the chip can't be removed easily without recoding the software.And on to the sensor to detect your car parked too long in the lot getting you a fine.On the very edge of the pcb is this 3-axis magnetic field sensor, some flavour of the 5883 type, might be the QMC5883http://wiki.sunfounder.cc/images/7/72/QMC5883L-Datasheet-1.0.pdfAll in all the design of the whole sensor assembly is textbook style. There is nothing different than in the datasheets for each component.Remarkable to note: everything is directly powered from the battery; there is no power management or supply circuitry anywhere.The big hole in the board is room for a plastic protrusion in the case to provide some more stability against pressure from a cars weight.The sensor assembly is not to be serviced in any way. unknown battery life (the manufacturer doesn't tell) or other faults lead directly to the disposal of the sensor. Not sure if the battery level is monitored by the processor.Most of the intelligence is in the software on the backend servers; no clue what is done there.There are developments or demo kits available for about 300,- € a sensor plus additional costs for the application.Despite being a total waste of resources and obviousliy designed to make a quick profit , this whole parking lot control stuff is just a pita.And to be honest: if I were interested in this specific system and tried to get some more info via the given webpage I would instantly run away. Only marketing wank and datasheets only upon registration.And on top: "our system works with combined magnetic and radar sensors. "A line further: Magnetic sensor detects the car.Nope. No radar present.Talking about waste: there are NO markings on the plastic showing what kind of plastic it is in order to be recycled. There is no labeling at all, even not the 'don't throw into the bin' symbol.Quite sure this cannot be legal in europe.Edit: I messed up the photo-thingy. There are all there but you cannot see them. I attach them here in order of the description above.

author: Stefan .
author_rank: Contributor
timestamp: May 14, 2023, 10:01:38 pm
content: Not interesting at all? No questions or (thats what I hoped for) disassembly of similar devices?

author: tooki
author_rank: Super Contributor
timestamp: May 18, 2023, 10:51:00 am
content: I think you were so thorough that there’s not much to ask!I haven’t seen those in Switzerland much. Parking garages are the only places I’ve seen systems like that here. I don’t think I’ve ever seen one in open parking lots.