nabilt

Joined 15 years ago

Karma
321
Submissions
101
Member since
Mar 12
https://nabil.me
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Recent submissions

Comment · 2 months ago
Comment · 3 months ago
That would simplify things. How do nodes usually identify themselves to be able to join the network? Maybe a QR code?
Comment · 3 months ago
I think most ZigBee and Thread chips use 2.4 GHz which limits distance. A lot of water meters are underground on the front yard somewhere so sub gigahertz radio would penetrate better. The modulation scheme of LoRa also allows for greater distance at the cost of data rate. It's also super low power.
Comment · 3 months ago
So if I understand correctly, they used hard coded constants to generate keys that only have 44 bits of entropy, which is brute forcible for $10, but you have to do it per device. They presumably did this to make pairing the bridge and sensor easier while not using a static key for all devices. Not the worst compromise I guess.

I've been working on an open source solution on and off for a number of years called http://y-drip.com. It uses Wi-Fi so battery life is only a few months and range is limited. My next design is probably going to use LoRa, but this complicates things a lot because now I have two devices (bridge and sensor) that need to be paired, support over-the-air updates, etc.

What's the best way to have them share keys without adding expensive hardware like Bluetooth or NFC. The sensor also needs to be waterproof so there's no exposed ports. Increasing from 44 bits to 128 would help, but if the key generation is done over the air it can be sniffed right?

Comment · 8 months ago
Comment · 9 months ago
Comment · 1 year ago
Comment · 1 year ago
Comment · 1 year ago
Comment · 2 years ago
I started working on my opensource water meter again (https://y-drip.com/). Hardware is basically done so I'm working on the backend website for those that don't want to setup their own server. More technical details here: https://hackaday.io/project/191398-ydrip
Comment · 2 years ago

  Location: Toronto
  Remote: Yes
  Willing to relocate: Yes
  Technologies: C, Python, JavaScript, HTML, Qualcomm Snapdragon, STM32, AVR, ESP32, Silicon Labs Gecko, Nordic nRF
  Résumé/CV: https://nabil.me/wp-content/uploads/2024/08/nabil_tewolde_resume.pdf
  Email: work@[domain above]
---

I'm a seasoned software engineer with extensive experience in embedded systems, real-time communication, and full-stack development. My background includes designing innovative hardware and software solutions for various applications.

Key Projects:

    - Real-time Audio Communication Device: Developed a device supporting 16 participants over 700 meters with 18-hour battery life using STM32 and Silicon Labs EFR32.
    - Android ROM Customization: Customized Android ROM for a video kiosk, added native USB camera support, and developed an over-the-air A/B update method.
    - Innovative Water Meter Solution (Y-Drip): Designed a product for real-time water usage data and leak detection with ultra-low power consumption.
    - Full Stack Development (Scalp Radar): Created a SAAS website for futures traders using Python, Django, and C#, with an automated license management system.
I'm currently seeking opportunities to leverage my skills in innovative projects, whether in embedded systems, software development, or full-stack applications. Open to remote work or on-site positions.
Comment · 2 years ago
Hey HN,

I recently launch a side project selling software on Shopify and needed a way to for users to manage their software license. Shopify's sample Django app was out dated and didn't implement all of the security features so I've improved it and wrote a guide on how to set it up.

I've found Shopify to be a good platform for selling software minus a few things like subscriptions. It's nice to have most of the e-commerce features like discount codes, analytics, order management taken care of. The only limitation is their free subscription management app is very limited so you might need to pay or build an app to take care of that.

Hopefully, this should give you a head start on adding custom functionality to your next Shopify side project.

Comment · 2 years ago
Thanks, good to know. I may need to request a 3A 1U in that case.

I didn't know iDRAC could measure real time power usage. Pretty amazing.

Comment · 2 years ago
This is a pretty cool solution. I didn't know the capabilities of USB4 before this.

The comparison with the Dell r630 power numbers got me interested since I just purchased a Dell r430 to host my site so I decided to benchmark mine.

Specs:

  * 2x Xeon E5-2680 v3 (same CPU)
  * 64GB RAM
  * 2x power supply (can't remember if it's 500W or 750W each and too lazy to look)
  * 1 SSD & 1 7300 RPM HDD
  * Ubuntu server 22.04.3 LTS
Using a Kill-A-Watt meter I measure ~100 watts after boot. Running sysbench (sysbench --test=cpu --threads=12 --cpu-max-prime=100000 --time=300 run) I get up to ~220 watts.

If my calculations are correct that's 72 kW per day or $11.05 per month at idle:

  0.1 kW * 24 hours * 30 days = 72 kWh
  72 kWh * 15.34 cents/kWh = $11.05 
and 158.4 kW or $24.3 per month during load:

  0.22 kW * 24 hours * 30 days = 158.4 kWh
  158.4 kWh * 15.34 cents/kWh = $24.3
I'm not sure of OP's use case, but these numbers are probably more realistic than using the max wattage of the power supply for most people. I will still be hosting in a co-location for the reliable internet and so I can sleep without the sound of a jet engine taking off. Those fans are loud!

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