![\"CloudFlare](\"https://ctmlr.dev/img/I4rqZ-z6Bp-300.png)
Backblaze offers 10 GB of storage for free and CloudFlare offers free data transfer from backblaze, combining these services you can host a fast and reliable static website with SSL for little to no cost.
\nTo get started you'll need a public B2 storage bucket in Backblaze and a DNS zone in Cloudflare.
\nThis worker script proxies requests to the B2 origin and caches the response on Cloudflare.
\nexport default {
async fetch(req, env, ctx) {
// Cached response
let res = await caches.default.match(req);
if (res) return res;
// Fetch object from origin
let reqPath = new URL(req.url).pathname;
reqPath = reqPath.replace(/\\/$/, ''); // Remove trailing slash
if (!reqPath.includes('.')) // Check file extension
reqPath += '/index.html'; // Default to index page
res = await fetch(env.ORIGIN + reqPath);
if (res.status === 404) // Object not found
res = await fetch(env.ORIGIN + '/404.html');
// Configure content cache
res = new Response(res.body, res);
const ttl = res.headers.get('content-type').startsWith('text')
? 14400 : 31536000; // Cache text 4 hours, 1 year default
res.headers.set('cache-control', 'public, max-age=' + ttl);
// Cache and return response
ctx.waitUntil(caches.default.put(req, res.clone()));
return res;
},
};![\"Cloudflare](\"https://ctmlr.dev/img/vCvgQs9925-300.png)
Route all requests through the workerCustom domain creates a DNS recordORIGIN is the public bucket URLhttps://f002.backblazeb2.com/file/<BUCKET_NAME>![\"A](\"https://ctmlr.dev/img/EwhfMzSC8F-300.png)
I like the portability of mini-ITX case and the NZXT H210 has room for a full-size power supply and graphics card but is still reasonably luggable. However I ran into trouble when I brought home a Gigabyte 7900 XTX, the mounting bracket provided only works in a fullsize ATX case.
\nTo solve this I made a custom 3D-printed support bracket in FreeCAD, it mounts the card to the front of the case with some heat-set inserts and M3 hardware.
\n![\"A](\"https://ctmlr.dev/img/iY5jKRHVCA-300.png)
Print with 100% infill
\n![\"Case](\"https://ctmlr.dev/img/welsRaqeUk-300.png)
![\"A](\"https://ctmlr.dev/img/wEdX6D_IO9-300.png)
In our computer room we have a TV but you can't hear it with headphones on. With a Raspberry Pi and a Griffin iMic USB audio adapter I'm able to capture stereo audio and stream it into Discord.
\nconst mic = require('mic');
const Discord = require('discord.js');
const config = {
mic: {
rate: 48000,
channels: 2,
device: \"plughw:CARD=system,DEV=0\"
},
discord: {
token: \"<bot-token>\",
guild: \"<server-name>\",
channel: \"<channel-name>\"
}
}
const client = new Discord.Client();
client.login(config.discord.token)
.catch( () => {
console.log('Unable to log in with provided token.');
process.exit();
});
// Start audio capture
let micInstance = mic(config.mic);
let audioStream = micInstance.getAudioStream();
client.on('ready', () => {
// Filter channels down to voice channels in the guild
let channels = client.channels.filter( channel => {
return channel.guild.name === config.discord.guild && channel.type === 'voice';
});
// Find channel by name
let channel = channels.find('name', config.discord.channel);
if(!channel) {
console.log(`Unable to find voice channel ${config.discord.channel} in ${config.discord.guild}`);
process.exit();
}
// Connect to the channel
channel.join()
.then( connection => {
console.log('Connected...');
// Start the audio stream
connection.playConvertedStream( audioStream );
micInstance.start();
})
.catch( error => {
console.log('Unable to connect to the voice channel', error);
process.exit();
});
});I put a G5RV antenna up to try out my Yeasu FT-900 however I found that the internal tuner didn't have enough range to match this antenna. In a hurry to get on the air, and on a college kid budget, I threw together a junk bin L network antenna tuner to get it going.
\n![\"A](\"https://ctmlr.dev/img/bCcQB7yBFw-300.png)
The variable inductor is wound with solid core 14 gauge wire around a cardboard tube with taps at regular intervals. The inductor value can be tuned by connecting an alegator clip at different points. The variable capacitor was scrapped out of an old tube AM radio and the coax connectors were pulled from some junk CB radios.
\nThe capacitance range isn't quite enough with the variable capacitor so I added additional capacitors in parallel. With this makeshift tuner I was able to get the SWR down to just under 1.5 on the G5RV antenna using the radio's internal tuner to fine tune the impedance match. I had to keep the transmit power below 50 watts but I was able to make contacts on 80, 40, and 20 meters.
\n", "date_published": "2012-12-16T00:00:00Z" },{ "id": "https://ctmlr.dev/posts/simple-am-transmitter-receiver/", "url": "https://ctmlr.dev/posts/simple-am-transmitter-receiver/", "title": "Simple AM Shortwave Transmitter", "content_html": "\nI was experimenting with RF oscillator circuits and built a simple low power shortwave transmitter and reciver set with minimal parts and complexity.
\n![\"An](\"https://ctmlr.dev/img/shortwave-am-transmitter-circuit.png\"){kind=spacer}
The transmitter is made with a Hartley oscillator. Transistor Q1 provides feedback to sustain the resonant LC tank circuit and Q2 modulates the signal by attenuating the oscillator's output to modulate the amplitude. This is a very simple design with no amplification and does not transmit very far.
\nThe AM receiver is also very simple with only three standard NPN transistors total. In place of the 120k regenerative feedback resistor I used a vairable resistor for fine tuning the gain.
\nThe resonant frequency of the transmitter and receiver is determined by the inductor L and the capacitance C values in the tank circuit.
\n$$ f = \\frac{1}{2\\pi\\sqrt{LC}} $$
\nI measured my variable capacitor's max value 290 pF and made coils that are roughly 1.78 µH which makes the tank circuit resonant in the 7 MHz shortwave band.
\nThe resonant frequency formula can be used to find the inductance L value
\n$$ L = \\frac{1}{(2\\pi f)^2 C} $$
\nUsing $ f = 7$ MHz and $C = 290$ pF
\n$$ L = \\frac{1}{(2\\pi \\times 7 \\times 10^6)^2 \\times 290 \\times 10^{-12}} $$
\n$ L = 1.783$ µH
\nI made an inductor by wrapping enamel copper wire around a quarter inch diameter soda straw.
\nI used this formula to find the value of an air-core inductor
\n$$ L = \\frac{d^2 \\cdot n^2}{18d+40l} $$
\nExperimenting with some values I found these dimensions bring me close to my target inductance.
\n| \n | \n |
|---|---|
| Diameter | \n$1/4$" | \n
| Length | \n$3/4$" | \n
| Turns | \n$31$ | \n
![\"A](\"https://ctmlr.dev/img/FrX7GJHZXF-300.png)
I was playing around with some 7490 decade counters and ended up building a digital clock.
\nThe first trick was getting an accurate 1 second time base. There are a few options here, you can divide the 60 Hz AC line frequency down to 1 Hz or you can build a crystal oscillator and divide that frequency down with more counters. With limited space on this breadboard I ended up taking a 1 Hz oscillator circuit out of an analog quartz clock I found in the junk box.
\nThere are a few different ways you can wire these quratz clock circuits. It took some experimentation to find a configuration that worked. With my clock I didn't have to run the outputs through diodes or transistors. Each output is ½ Hz and simply wiring them together worked just fine. I powered this oscillator from the 5 volt supply by wiring a current limiting diode, in this case an LED, across the power connections. This added an unexpected "feature" where the LED blinks off every second.
\n![\"Circuit](\"https://ctmlr.dev/img/digital-clock-schematic.png\")
The time is kept by six 7490 decade counters. The 1 Hz clock goes into a 7490 wired up as a mod 10 counter (for seconds 0-9). The output of the mod 10 counter then goes into a 7490 wired as a mod 6 counter (for seconds 0-5). That circuit is then duplicated for the minutes (0-59). The hours are then counted by two 7490s wired up as a mod 24 counter (0-23).
\nThe tens of seconds are displayed by 3 LEDs in binary. The 7 segment displays are driven by four 4511 BCD-to-7 segment decoders. I needed thirty-three 100 Ohm resistors in total for all the displays and LEDs.
\n", "date_published": "2010-04-01T00:00:00Z" } ] }