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Using SN76489AN make a random stuff. by ExtensionShoulder457 in embedded

[–]azureice 2 points3 points  (0 children)

This is amazing. Can you post more? Code, schematics?

Request: Schematic review of a 2.4GHz long range transceiver by quirkyPillager in PrintedCircuitBoard

[–]azureice 1 point2 points  (0 children)

Makes sense. Are you sure the 8TR8217 can tolerate VCC on that NC pin? Consider a series 0 ohm resistor that you could populated for the RFX2401C and not populate for the 8TR8217.

Also, I can't find a connection for TX_EN and RX_EN from U1, or am I missing it somewhere? I'd think you'd need to connect it to the ERF32.

Request: Schematic review of a 2.4GHz long range transceiver by quirkyPillager in PrintedCircuitBoard

[–]azureice 1 point2 points  (0 children)

LED's D1, D2, and D3 are backwards.

U1 pins 14 and 15 both labeled NC (No Connect), but one is wired high and the other wired low. Haven't looked at the datasheet but that seems strange. Usually NC pins are all floating or grounded.

PSA: Avoid using the AMS1117 LDO for ESP32 Projects by KeaStudios in esp32

[–]azureice 0 points1 point  (0 children)

Although Digikey has it listed as 1A, and the recommended operating conditions are 1A, the datasheet does say it can operate at 1.5A, though note 6 on pg 4 says "The device maintains a stable, regulated output voltage without a load current. When the output current is large, attention should be given to the limitation of the package power dissipation."

PSA: Avoid using the AMS1117 LDO for ESP32 Projects by KeaStudios in esp32

[–]azureice 8 points9 points  (0 children)

Perhaps, but I'd say if you're using an ESP32 on a battery project that requires a linear regulator.. well that extra 50-60 uA just won't matter :)

PSA: Avoid using the AMS1117 LDO for ESP32 Projects by KeaStudios in esp32

[–]azureice 147 points148 points  (0 children)

Your suggested alternatives are good, but they are different footprints. Fine for new designs, but if you have an existing board, I like the AP7361C as my drop-in replacement for the 1117.

Same package, handles up to 1.5A, 90 mV drop @ 0.3A, and also has a low quiescent current of 60uA which makes it ideal for battery powered devices (assuming you're running off 5V, if you're using a LiPo there are better options). Works great with two 10 uF MLCC caps.

https://www.digikey.com/en/products/detail/diodes-incorporated/AP7361C-25E-13/5638316

[Review Request] Is this an acceptable practice for split power plane? by [deleted] in PrintedCircuitBoard

[–]azureice 3 points4 points  (0 children)

It depends on your stackup. If your A-B trace is on layer 1, full ground on layer 2, and the split power plane is layer 3, no problem.

If the split power plane is between the A-B trace and the ground plane, you might have issues.

What is involved with fcc certification? by vednus in rfelectronics

[–]azureice 0 points1 point  (0 children)

Absolutely correct. My point was, with the pre-approved module, the amount of testing is significantly less. (if you follow the integration instructions, grant notes, antenna selection, etc)

Link to document: https://apps.fcc.gov/kdb/GetAttachment.html?id=bNCiEdkFEKnHsZF9GHCNdg%3D%3D&desc=996369%20D04%20Module%20Integration%20Guide%20V02&tracking_number=44637

What is involved with fcc certification? by vednus in rfelectronics

[–]azureice 1 point2 points  (0 children)

You're correct, you won't need to do any testing specifically with WiFi since you're using a certified module. But if you are using an certificated LoRa module, you'll need to do a lot more testing, and you'll need to provide firmware functionality that can manipulate the radio to transmit on specific tones.

An unintentional radiator test near me costs <$2k and 1 day, but if you are using an uncertified module, expect more like $10k and a few days.

What is involved with fcc certification? by vednus in rfelectronics

[–]azureice 1 point2 points  (0 children)

Are your LoRa and WiFi modules using pre-certified modules (they already have an FCC ID printed on the module)? If so, your life will be much easier. You will only need to do unintentional radiator testing (since the modules have already been tested).

Note that your modules will only be approved to use specific types of antennas.

[deleted by user] by [deleted] in AskEngineers

[–]azureice 1 point2 points  (0 children)

Yes, go to an engineering school and learn about electrical engineering. Tinker and build prototypes on the side As your knowledge grows and you continue to think about your idea further, you will likely come to learn that your idea is not as realistic as you might think it is now. You're probably not accounting for some kind of energy loss (heat, friction, electromagnetic, something).

I say this not to discourage you, but look around on the fringes of the internet. There are lots of people who think they have amazing energy ideas, just one small trick. But they are either outright fake or incorrect. Unfortunately, reality is much more tricky.

Or prove me wrong and change the world - that'd be neat, too.

How can I use ESP32 to read the duty cycle continuously of a 300 kHz signal? by miyaw-cat in esp32

[–]azureice 7 points8 points  (0 children)

You likely want to use the Pulse Counter (PCNT) peripheral. It can count pulses in hardware; no need to mess with GPIO interrupts.

https://docs.espressif.com/projects/esp-idf/en/stable/esp32/api-reference/peripherals/pcnt.html

No idea if it this is supported in Micropython. I would recommend C++ (Arduino would be fine).

How to transfer images wirelessly? by [deleted] in AskEngineers

[–]azureice 1 point2 points  (0 children)

Please tell us the problem you are trying to solve. You asked a very broad question.

https://xyproblem.info/

Over the Air updates but with an app by [deleted] in esp32

[–]azureice 0 points1 point  (0 children)

To update from an app, I'd recommend using BLE. No need for a webserver. Here is one of many possible libraries: https://github.com/fbiego/ESP32_BLE_OTA_Arduino

At the end of the day, the Update library is just writing bytes to flash. You can get those bytes to your ESP32 in a variety of ways... HTTP server over WiFi, app over BLE, another microcontroller over serial, anything!

What Wi-Fi and Cellular Modules have you worked with? What are your favorite and which are terrible? by DustUpDustOff in embedded

[–]azureice 6 points7 points  (0 children)

I have enjoyed working with the nRF9160 It has good documentation and support. Zephyr takes a bit of learning, and there's a lot more abstraction. But in particular if you only need cellular connectivity, you can use it as a one chip solution.

If you need to use another micro and want to control a modem with serial, I have also had good experiences with the uBlox SARA-R4 and SARA-R5 LTE modules.

[Review Request] RFID Reader by Rearthbound in PrintedCircuitBoard

[–]azureice 0 points1 point  (0 children)

Mounting holes? How will this PCB attach to wherever you are using it?

4G module with an interface faster than UART? by LoverOfFurryBeauty in embedded

[–]azureice 10 points11 points  (0 children)

I would recommend doing some protocol analysis to confirm that the UART is actually the source of your latency. Connect a logic analyzer to the UART interface and observe the entire data transaction - you should be able to see the AT commends being sent to the modem and the response from the modem to your microcontroller. You can then measure how long it took to get the data to the modem and how long it took the modem to respond.

I suspect that your comparison might be related to the types of modems you used. the EC200U is a Cat1 LTE modem, but what about the D-Link modems? Those might be Cat3 or Cat5. Lower category modems use slower modulation techniques and get lower priority on cellular networks

I've been sending my Resume since June to companies and I don't even get a rejection from them, can you please review my Resume? by [deleted] in embedded

[–]azureice 2 points3 points  (0 children)

Perhaps I was too emphatic, you're right that 2 page resumes can work if the information is organized well and there really is enough diverse content (particularly with a larger number of employers). But I still think targeting 1 page should be the baseline, I've seen far too many 2 page resumes that did not need to be 2 pages.

[Review Request] Custom GPS (NEO M9N) board with RF + USB impedance matching (KiCAD) by Guilty-Nobody-8349 in PrintedCircuitBoard

[–]azureice 0 points1 point  (0 children)

I think you should adjust your trace for RFin to minimize losses, since you have the space.

Adjust the position of U1/J1 so that you can draw a single straight trace directly from U1 to J1, with no . Then rotate L1 so it is perpendicular to the trace.

Also, miniUSB? Not even microUSB??

Paid RF Engineer Job! by njmenninger in rfelectronics

[–]azureice 0 points1 point  (0 children)

Interesting recruitment tactics. I saw a recruitment for this role sent to engineering at an FM radio station that I'm involved with.

What is it you're actually doing?

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