WhiskeyTangoHotel.Com: usb

Showing posts with label usb. Show all posts

Wednesday, February 28, 2024

USB Jump Battery "Hack" for Meshtastic WisBlock Base Board

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Meshtasic is cool. The quickie description from their website is: "An open source, off-grid, decentralized, mesh network built to run on affordable, low-power devices". It's a way to send SMS type messages without the use of the internet, cell phone infrastructure, etc. The hardware is cheap and there are Android and iPhone apps to that support it.

We wanted to experiment with Meshtasic and purchased the RAKwireless WisBlock Base Board from Rokland. One nice thing about the WisBlock Base Board are the many supported 'plug and play' modules that allow for easy expansion.

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Enough about that... the problem we had was running the WisBlock base board with battery power. There is a right way to do this and there is the way we did it. The right way is to use a rechargeable LiPo battery with the connector already installed.

But... this is what we did mainly because we already had a drawer full of USB portable charging battery bricks. Like many other USB powered devices, the current draw from the WisBlock Base Board is so low that when powering it from a USB portable charging battery the portable charger will just shut down thinking there is nothing connected to it. Our fix was to add a 100 ohm load. The WisBlock makes this super easy from the on board BATTERY socket (see "right way" above).

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Here's the current draw (~15mA) without the 100 ohm load added. All of our tested USB portable charging battery bricks would shut down:

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We plug in the 100 ohm resistor and now all of our tested USB portable charging battery bricks stay activated with ~53mA current draw:

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Does it use more juice? Of course it does, but even the small lipstick battery shown will last for days and that's good enough for our use.

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FWIW, here is what our Meshtasic portable rig looks like:

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Sunday, May 30, 2021

Remote CW Straight Key [FlexRadio and RemoteHams.Com]

Note: As presented this project requires a FCC Amateur Radio license. It's not hard to get and it is a fun and rewarding hobby. Also, learning Morse code is no longer a requirement.

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As a remote ham radio operator that enjoys using a manual CW (Morse code) straight key we were presented with two problems:

RemoteHams.Com remote manual keying
FlexRadio remote manual keying

Since both require slightly different hardware wiring to the PC running the remote rig, we set out to make something that would be a universal connection regardless of which platform we are using.

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The hardware connection is simple and shown below. It does require a USB/RS-232 adapter and using the RS-232 terminal block break out module shown makes things easier. There are many example of these two items on Amazon.Com, etc.

For both applications software is needed as well.

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For our RemoteHams.Com solution go here.

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For the FlexRadio solution you will need to install the excellent and easy to use Remote Keyer Interface software. Follow the RKI link for the software and you will also find the very helpful RKI message board that I personally proved is helpful and tolerant of 'stupid' questions. Seriously, the software has great documentation and even though I asked a "RTFM" question I got helpful direction from the forum. After you install and run the RKI software you will see this screen:

Make the remote connection to your FlexRadio via your SmartLink login and select the correct COM Port for your (now) USB straight key. Verify the other options are selected per above screen shot and you should be good to go.

BTW, Remote Keyer Interface software has several other cool features in addition to this simple application.

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Summary: My remote CW manual straight keying problems are solved!

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Wednesday, May 26, 2021

The Tale of Three USB Chargers

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Everyone seems to have a box full of USB chargers. Well, we do anyway and decided to pick two random "no name" chargers and pit them up against an official Apple USB charger.

The test setup was the same for each USB charger. We swept a load that increases from 100mA until the USB charger went into protection (no voltage output). We then checked EMI/RF Noise and 'vampire drain'.

EMI/RF Noise is a big concern. EMI/RF can have a negative effect on WiFi, Bluetooth, ham radio, and pretty much any radio signal in the area. Measuring with a Spectrum Analyzer the Apple was by far the most RF quite. The White "no name" was extremely EMI/RF noisy with the Black "no name" being pretty bad as well.

"Vampire drain" or standby power is how much energy the charger uses when just plugged into the wall doing nothing. The Apple won in this category as well.

My opinion, get the Apple or other well made USB charger and avoid the "no names", The Apple uses less standby power and should not have a negative effect on your or your neighbors wireless equipment. The Apple power output meets spec as well and is more linear until protection kicks in. The Apple is just better and some "no names" are are just unsafe.

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