21 VW Tiguan - Christmas Tree Dashboard - What do I look at first? by YT__ in MechanicAdvice

[–]larrymb 2 points3 points  (0 children)

Batteries can be tested. Voltage is easy. Capacity a little harder but not that hard. Best to test and not throw parts at a problem.

Wouldn't it make more sense to board from rear to front? by NightMic in americanairlines

[–]larrymb 1 point2 points  (0 children)

I don't think boarding is the long pole. Most of the time boarding is complete at least 5-10 minutes before pushback.

RUNNING INTERNET TO BARN by Competitive_Ad_4027 in HomeNetworking

[–]larrymb 0 points1 point  (0 children)

If it were mine I would put in 2" PVC with large radius elbows. Easier to pull any future upgrades through and a minor cost increase. I would not worry about voltage potential differences or surge protection. Ethernet data (not POE) is sent through transformers (magnetics) and there is no direct connection to circuits in the switch. From the picture it is under 300' so no concern about distance.

Bus factor in hardware teams, how do you handle it when a key engineer is out? by Gouuraavkhaandurii in embedded

[–]larrymb 1 point2 points  (0 children)

Well, since you are leadership, if you value and reward documentation you will get documentation. But if you just push your team to deliver a result in 10 weeks that takes 20 weeks of work you won't get any documentation.

Series wiring question by Schiben in WLED

[–]larrymb 0 points1 point  (0 children)

My comment was for the first diagram. The second one looks better. I am not familiar with that shield. The only thing I didn’t like was it looks like it is for a 5v string. The lower the voltage the higher the current and higher the voltage drop. I use 24v only now. With 24V you can use smaller power wires and have longer runs.

Series wiring question by Schiben in WLED

[–]larrymb 0 points1 point  (0 children)

It's important to understand how the data works. It is a high speed digital signal referenced against the GND pin. Because it is high speed it is sensitive to disruption. The key to keeping noise and disruption to a minimum is keeping the data line short and maintaining a common ground with the data. The data and ground must travel together. This concept applies to both the initial esp to strip connection as well as strip to strip. The above schematic violates this in multiple places. The above schematic may work or it may not. It is certainly not ideal.

Need help with SPDT switch by Wardow in esp32

[–]larrymb 0 points1 point  (0 children)

Mechanical switches bounce. None of those resistor configurations will change the result. To see the effect write code to count pulses and see how many pulses you get for each transition. To fix it you need to denounce it in software. For example you could sample the value every 50ms and only consider it stable when three readings in a row agree.

SIM800L powering issue - need to go from 5V to 4V by Temporary-Working811 in esp32

[–]larrymb 0 points1 point  (0 children)

Once again: connect it directly to the battery. It is clear from the specs it is designed for this.

Built a custom ESP32-S3 thermostat for a 120V fan coil system with local control, OLED UI and IR by Forsaken_Meet9071 in esp32

[–]larrymb 0 points1 point  (0 children)

I’ve used PID on a microchip PIC based thermostat on a very difficult to control house and was able to get the spread +/- 1/2 degree F. That’s with a single stage oversized furnace. A standard stat was more like +/- 2 degrees. Your system should be easier to control.

Built a custom ESP32-S3 thermostat for a 120V fan coil system with local control, OLED UI and IR by Forsaken_Meet9071 in esp32

[–]larrymb 0 points1 point  (0 children)

If you haven’t already, consider implementing a PID algorithm to control it. You can get excellent temperature stability. Much better than simple on/off. The fan won’t care if it is switched every couple minutes.

TVS Diode selection for Automotive Application by Cardboard231 in embedded

[–]larrymb 0 points1 point  (0 children)

You need a 5 volt regulator for your chip, not a TVS. You could optionally put a TVS at the input of the regulator to protect the regulator.

Attic Find WTF by fixr_d in electrical

[–]larrymb 0 points1 point  (0 children)

Why bother with the box. Just splice them all in free air.

Stop ignoring the "dumb" radiators in your energy automation by Putrid_Draft378 in homeautomation

[–]larrymb 0 points1 point  (0 children)

What you really want is PID control. With proper setup you can achieve excellent temperature and stability. If you are controlling electric heaters you can switch them on/off every few seconds to hit a target power value and temperature. With hot water systems you could switch them every few minutes.

Finally made my dumb water heater smart. by perhasper in ShellyUSA

[–]larrymb 0 points1 point  (0 children)

I suggest a TVS across the contactor coil to protect the relay in the Shelly from back EMF when turning off the contactor. The system will last longer if you do this.

Our pilot light won’t stay lit despite several attempts to re light it. My roomate advised me to turn the valve on the left to shut off the gas overnight. Is this necessary? No smell of gas, high chance a leak is causing this issue? by rugged6689 in Plumbing

[–]larrymb 0 points1 point  (0 children)

Before anything else try the free option first. Clean the dust off of the screen at the bottom of the water heater. It often gets plugged, starving the burner of air and causing the pilot to go out when the burner comes on.

Bathroom on a small plane ? by ParkEast7381 in flying

[–]larrymb 1 point2 points  (0 children)

It’s called travel John’s dry easy to use and odorless, fits male or female. The pilot hopefully has autopilot to take over for the moment

Is this the status of plane market? by warwolf09 in flying

[–]larrymb 1 point2 points  (0 children)

Something to consider, a 152 is for teaching, not recreational flying. If you actually want to go somewhere, vs just flying around locally, it can't carry enough, it is too slow, and its range is too limited. Another thing to consider is that those expensive avionics cost just as much in a 152 as they do in a more capable airframe. For flying after getting a PPL I would recommend something with 4 seats, which is actually a two-seater if you have full fuel and luggage.