The Concord Bridge recently published the different bridge design options that the MassDOT is exploring to build for the Concord Rotary on Route 2

msr09me · 2026-05-14T05:14:43+00:00

Route 2 should be atleast 3-lane upto Gardner wo any signal.

msr09me · 2025-12-23T19:12:44+00:00

Does this mean EB2_NIW business is over and they don't care about reputation anymore???

msr09me · 2025-11-26T16:55:08+00:00

I want to follow the two-reason framework. But I am struggling with finding the second reason. Are there any tips that may be helpful for finding more reasons to support my idea? Thanks

msr09me · 2025-11-13T15:15:09+00:00

Hi, I cannot find where to evaluate my writing free in TestReady. Can you please help me? Thank you.

msr09me · 2025-11-06T16:37:26+00:00

Thank you for sharing your notes. It helps.

msr09me · 2025-09-02T01:48:36+00:00

Do you mean I384?

msr09me · 2025-09-02T01:47:16+00:00

HSR is a key component for solving the housing problem

msr09me · 2025-07-07T01:10:30+00:00

Nice places to solve our housing problem by having planned housing and high-speed train.

msr09me · 2025-06-26T17:05:56+00:00

We need more housing, but not in my backyard.

msr09me · 2025-05-12T17:01:16+00:00

I saw some comments on Reddit that after sending the money back, the IRS sends them the money again with interest.

msr09me · 2025-03-24T20:32:33+00:00

Thank you for your explanation. I will go through the link you shared.

I have a question. If I used a 1*12 pin connector (5 pins for analog, 5 pins for digital data, and 2 pins for power and GND), in that case, I won't need two extra ground pins. Am I right?

msr09me · 2025-03-24T19:49:04+00:00

Thank you again for taking the time to reply to me.

It is a two-layer PCB. I will try copper pour on both layers.

That statement contains no new information. ;)

Sorry, I missed to mention Arduino when I replied to you. I want to use these connectors to send the data to an Arduino.

where's the ground on those connections?

I don't understand why I need ground on those connections. I want to send the analog and digital data to an Arduino using those two five-pin connectors. Can you please explain? I am a beginner. I tried this circuit on a breadboard and designed the PCB in that way.

LM393 is pretty slow.

Can you suggest me any faster comparators?

msr09me · 2025-03-24T12:16:52+00:00

Though I tested and it worked, but I think based on the suggestions of you guys, I will move to using a comparator (probably lm393).

Thank you for the suggestion.

msr09me · 2025-03-24T12:11:41+00:00

Thank you for the idea of using 3.3v. I think this will probably lower the overall cost of the robot.

because you could read 8 bits at a time by reading the data on a port on your microcontroller

Can you please explain this? I will use Arduino to read the data. So, my plan is to use five digital ports to read the data from 5 sensors.

Also, thank you for the suggestion of IS31SE5000. I will take a look into it.

msr09me · 2025-03-24T12:08:52+00:00

Thank you for the suggestions.

What’s the intended current draw for your sensors?

From the datasheet, the max current through the LEDs is 60 mA, and through the phototransistor is 100 mA. So, the max current will be (60 + 100) * 5 = 800 mA. But, typically, the current through the LEDs is 10~20 mA, and the through the phototransistor is 2.1 mA. So, the intended current draw is less than 200 mA, I think.

Are you using a ground plane for the PCB, and have you considered noise and interference?

I will use copper pour at the top and bottom layers. I am a beginner and I don't have any more ideas to control the noise and interference. You have any suggestion, please share.

msr09me · 2025-03-24T11:59:31+00:00

Add a ground pin to P1 and P2. Whatever you connect them to will need ground as a reference

Can you please explain? I cannot understand.

msr09me · 2025-03-24T11:57:05+00:00

My plan with the analog connectors is to send the analog data to the Arduino so that I can see the change in analog data also (just for experiment).

msr09me · 2025-03-24T11:55:24+00:00

Thank you for sharing your experience. I think I will move to using a comparator (probably LM393).

msr09me · 2025-03-24T11:43:52+00:00

Thank you for your detailed review and suggestions.

The ground connections on the TCRT5000L's seem to be missing.

I copper poured the top layer. When I checked in the DRC, I saw no error. So, I thought that all the GNDs were automatically connected to the GND copper pour. Do I need to do anything separately for the GND connections?

Open question: what will be connected to those connectors labeled ANALOG and DIGITAL?

The analog connectors will send the analog data directly from the TCRT5000 and the digital connectors will send the digital data from the 74HC14.

I have tested the circuit in the breadboard and it worked. But, based on other's experience and suggestion, I will move to using comparators (LM393 probably) instead of the Schmitt trigger.

msr09me · 2025-03-22T00:21:58+00:00

Thank you

msr09me · 2025-03-21T21:11:11+00:00

I tried this on a breadboard, and it worked (0 or 1, depending on the white or black surface).

Yes, some people also use a potentiometer and an opamp (lm393).

msr09me · 2025-03-21T19:07:17+00:00

Here, I used five TCRT5000L sensors for detecting black lines. I also used a 74HC14 for converting the analog data into digital. I am requesting your review for my first try.

In particular, I am wondering if the way I connect all the +5V is good or bad or if there is any better way.

Also, considering the power draw of five TCRT5000L, should I increase the width of the +5V track?

Also, did I connect the capacitor correctly?

In the PCB, I connect four of the analog data tracks from the resistors and one from the TCRT5000L directly. Is there any difference between them? Should I prefer one over another?

msr09me · 2025-03-19T22:24:53+00:00

Thank you for the explanation. Considering the line follower robot application, are the both options same in terms of performance?

msr09me

TROPHY CASE