4 ms·

PCB Metro Map

124 points by zdw 5y ago

dismalpedigree 5y ago
Pretty cool. I admire your perseverance on it.
jalessio 5y ago
Wow, those look really nice! Reminds me of this project which I stumbled across recently: https://www.traintrackr.io/ https://www.traintrackr.io/
exmadscientist 5y ago
Pulling back soldermask is a useful trick to know if anyone's trying to do something like this themselves. It's another bit to play with: twice the number of visually distinct areas! And if you're willing to pay for multilayer boards, having different copper structures on layer 2 and (N-1) can create really interesting lighting effects. And never use JLCpcb if you care about quality silk. Still, nice project!
- contingencies 5y ago
  JLC "have" multiple factories, ie. they outsource board production to one of a number of third parties. You are mostly exposed to this with boards that do not have SMT components, since AFAIK SMT will automatically route your PCB to the SMT-capable PCBA (one factory only). I am really nonplussed with them recently for a number of reasons and have begun to reach out to PCBAs here in China independently. As I would prefer to have a decent frontend for handing off work (quote, pay, support, etc.) I hacked one together last night. Let me know here if anyone else would like such a service. Ideally you pick your own PCBA and both parties communicate via the platform. Conceptually reputation should accrue with volume, with turnaround times and quality issues recorded publicly.
c54 5y ago
> The Bay Area Map was actually the simplest one to do since the train system is so sparse. I honestly am not terribly excited about the train system here, but since I do live in the Bay Area, I felt like I should do it for completion’s sake. sigh Same, and I live in the Bay too
plandis 5y ago
I don’t have anything to add, but this is pretty cool!
Karliss 5y ago
Instead of attaching transistors to shift registers there are shift register with open drain outputs and led drivers with shift register like interface designed for usecase like this. Some of them even have constant current drivers builtin which would allow eliminating the resistors further simplifying the build although that might require higher supply voltages for longer LED chains which might not be ideal for this project. Attiny85 operates at the same <20Mhz as ATMega328 in arduino pro mini lack so first one being too slow shouldn't be a thing. From the screenshots it seems that output enable pin wasn't used so I assume fading was done by quickly changing picture. A better approach would be connecting the output enable pin of shift registers to hardware PWM output of microcontroller that way fading can be controlled independently from picture content and easily run frequency where flickering isn't visible even for camera. You wouldn't try to dim a monitor by rapidly changing the picture, same situation with LEDs.
- risbz 5y ago
  Expanding on this, for applications like this charlieplexing led drivers like the IS31FL3731 can make the layout even easier. They require fewer PCB traces and have built in individual PWM control. One chip can drive up to 144 LEDs, so even for the large maps 2 chips would be enough.
foldr 5y ago
Mounting the LEDs on the back can work quite well if you have some kind of reasonably reflective surface on the back. You don’t even need a hole in the PCB, just a gap in all of the copper layers. I used this approach in my light meter project: https://github.com/addrummond/mlm https://github.com/addrummond/mlm In this case the reflector is just plastic painted with gloss white. Also, awesome project!
Aissen 5y ago
In Paris, we used to have special boards at big stations: a map of the subway system, and a button board with one button per station in the city; if you pressed a button, the path would light on the map explaining how to reach it: https://spacefiction.files.wordpress.com/2017/11/indicateur_itineraires.jpg https://spacefiction.files.wordpress.com/2017/11/indicateur_... Those appeared in 1937, so they're very old tech; it would be fun to have a pocket version. They've since disappeared and been replaced by touch screens, but those are just not the same. https://spacefiction.fr/2017/11/06/patrick-modiano-et-la-memoire-des-panneaux-indicateurs-lumineux-ditineraires-de-la-ratp-patrick-modiano-and-the-memory-of-ratp-illuminated-itineraries-panels/ https://spacefiction.fr/2017/11/06/patrick-modiano-et-la-mem...
leoedin 5y ago
Did the author consider bottom firing LEDs? (https://www.kingbrightusa.com/category.asp?catalog_name=LED&category_name=KCReverse+Mount+SMD+LED&Page=1 https://www.kingbrightusa.com/category.asp?catalog_name=LED&...) - they are like SMD LEDs, but the light comes out the bottom - the footprint needs to include a hole between the pads for the light to come through. Seems like a good solution for this problem.
- formerly_proven 5y ago
  You can also use buried components, which are sandwiched between layers inside the PCB. This of course requires a thick PCB and is really expensive. Though it would be quite nice for an art piece I suppose, zero exposed circuitry, everything buried. You could achieve a similar effect for this particular project by just ordering ~four PCBs with the necessary cutouts and gluing them together yourself, as connectivity between the PCBs isn't really required.
JorgeGT 5y ago
A super cool next step would be to track the actual trains with the LEDs, is there any city with an open API for that?
- amelius 5y ago
  And the next step: hover your mouse over a train and see information such as speed, whether it is on schedule, etc.
- smagoun 5y ago
  Boston’s MBTA has an API, and sells a live-updating PCB train tracker: https://www.mbtagifts.com/products/mbta-dual-direction-traintracker-updates-in-real-time https://www.mbtagifts.com/products/mbta-dual-direction-train...
- robin_reala 5y ago
  Not sure where Matthew gets the data from, but he’s got a page with live London tube train positioning (updated today with the two new Northern Line stations): https://traintimes.org.uk/map/tube/ https://traintimes.org.uk/map/tube/
rsynnott 5y ago
Irish trains used to have LED maps on the trains themselves, showing position. Though they only showed the relevant line, so were a lot less intricate than this. They were also often just wrong; fun as they were it's probably just as well that they got rid of them.
- Y_Y 5y ago
  Also there are very few lines with very few intersections. You will have to change train at Limerick Junction though.
  - rsynnott 5y ago
    The Dublin commuter network's probably about as complex as the Bay Area one shown in the article, but the LED maps never showed the whole thing, only the specific line.

124 points by zdw 5y ago

Pretty cool. I admire your perseverance on it.

Wow, those look really nice! Reminds me of this project which I stumbled across recently: https://www.traintrackr.io/ https://www.traintrackr.io/

exmadscientist 5y ago

Pulling back soldermask is a useful trick to know if anyone's trying to do something like this themselves. It's another bit to play with: twice the number of visually distinct areas! And if you're willing to pay for multilayer boards, having different copper structures on layer 2 and (N-1) can create really interesting lighting effects. And never use JLCpcb if you care about quality silk. Still, nice project!

contingencies 5y ago
JLC "have" multiple factories, ie. they outsource board production to one of a number of third parties. You are mostly exposed to this with boards that do not have SMT components, since AFAIK SMT will automatically route your PCB to the SMT-capable PCBA (one factory only). I am really nonplussed with them recently for a number of reasons and have begun to reach out to PCBAs here in China independently. As I would prefer to have a decent frontend for handing off work (quote, pay, support, etc.) I hacked one together last night. Let me know here if anyone else would like such a service. Ideally you pick your own PCBA and both parties communicate via the platform. Conceptually reputation should accrue with volume, with turnaround times and quality issues recorded publicly.

c54 5y ago

> The Bay Area Map was actually the simplest one to do since the train system is so sparse. I honestly am not terribly excited about the train system here, but since I do live in the Bay Area, I felt like I should do it for completion’s sake. sigh Same, and I live in the Bay too

plandis 5y ago

I don’t have anything to add, but this is pretty cool!

Karliss 5y ago

Instead of attaching transistors to shift registers there are shift register with open drain outputs and led drivers with shift register like interface designed for usecase like this. Some of them even have constant current drivers builtin which would allow eliminating the resistors further simplifying the build although that might require higher supply voltages for longer LED chains which might not be ideal for this project. Attiny85 operates at the same <20Mhz as ATMega328 in arduino pro mini lack so first one being too slow shouldn't be a thing. From the screenshots it seems that output enable pin wasn't used so I assume fading was done by quickly changing picture. A better approach would be connecting the output enable pin of shift registers to hardware PWM output of microcontroller that way fading can be controlled independently from picture content and easily run frequency where flickering isn't visible even for camera. You wouldn't try to dim a monitor by rapidly changing the picture, same situation with LEDs.

risbz 5y ago
Expanding on this, for applications like this charlieplexing led drivers like the IS31FL3731 can make the layout even easier. They require fewer PCB traces and have built in individual PWM control. One chip can drive up to 144 LEDs, so even for the large maps 2 chips would be enough.

foldr 5y ago

Mounting the LEDs on the back can work quite well if you have some kind of reasonably reflective surface on the back. You don’t even need a hole in the PCB, just a gap in all of the copper layers. I used this approach in my light meter project: https://github.com/addrummond/mlm https://github.com/addrummond/mlm In this case the reflector is just plastic painted with gloss white. Also, awesome project!

Aissen 5y ago

In Paris, we used to have special boards at big stations: a map of the subway system, and a button board with one button per station in the city; if you pressed a button, the path would light on the map explaining how to reach it: https://spacefiction.files.wordpress.com/2017/11/indicateur_itineraires.jpg https://spacefiction.files.wordpress.com/2017/11/indicateur_... Those appeared in 1937, so they're very old tech; it would be fun to have a pocket version. They've since disappeared and been replaced by touch screens, but those are just not the same. https://spacefiction.fr/2017/11/06/patrick-modiano-et-la-memoire-des-panneaux-indicateurs-lumineux-ditineraires-de-la-ratp-patrick-modiano-and-the-memory-of-ratp-illuminated-itineraries-panels/ https://spacefiction.fr/2017/11/06/patrick-modiano-et-la-mem...

leoedin 5y ago

Did the author consider bottom firing LEDs? (https://www.kingbrightusa.com/category.asp?catalog_name=LED&category_name=KCReverse+Mount+SMD+LED&Page=1 https://www.kingbrightusa.com/category.asp?catalog_name=LED&...) - they are like SMD LEDs, but the light comes out the bottom - the footprint needs to include a hole between the pads for the light to come through. Seems like a good solution for this problem.

formerly_proven 5y ago
You can also use buried components, which are sandwiched between layers inside the PCB. This of course requires a thick PCB and is really expensive. Though it would be quite nice for an art piece I suppose, zero exposed circuitry, everything buried. You could achieve a similar effect for this particular project by just ordering ~four PCBs with the necessary cutouts and gluing them together yourself, as connectivity between the PCBs isn't really required.

JorgeGT 5y ago

A super cool next step would be to track the actual trains with the LEDs, is there any city with an open API for that?

amelius 5y ago
And the next step: hover your mouse over a train and see information such as speed, whether it is on schedule, etc.
smagoun 5y ago
Boston’s MBTA has an API, and sells a live-updating PCB train tracker: https://www.mbtagifts.com/products/mbta-dual-direction-traintracker-updates-in-real-time https://www.mbtagifts.com/products/mbta-dual-direction-train...
robin_reala 5y ago
Not sure where Matthew gets the data from, but he’s got a page with live London tube train positioning (updated today with the two new Northern Line stations): https://traintimes.org.uk/map/tube/ https://traintimes.org.uk/map/tube/

rsynnott 5y ago

Irish trains used to have LED maps on the trains themselves, showing position. Though they only showed the relevant line, so were a lot less intricate than this. They were also often just wrong; fun as they were it's probably just as well that they got rid of them.

Y_Y 5y ago
Also there are very few lines with very few intersections. You will have to change train at Limerick Junction though.
- rsynnott 5y ago
  The Dublin commuter network's probably about as complex as the Bay Area one shown in the article, but the LED maps never showed the whole thing, only the specific line.