Category Archives: Electronics

Doing some RF spectrum analyser stuff

Having experienced some major WIFI problems over the years, with the overly crouded 2.4 ISM band. I decided to dust of the good old CC2500 chip, and get it running, properly. The reason for this chip? the 8-bit RSS value you can acquire from it. These day’s, the very cheap NRF24L01+ is rather nice, and cheap, but with a 1bit RSSI ‘threshold’, not very useful for these kind of setups.

rfexplorer
RFExplorer

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Fixing BMW parking sensors

A friend had a noticed that his parking-sensors where no longer working from his BMW 1

After he examined his OBD, he noticed that the parking-sensory board wasn’t working properly (read missing)

Probing the ODB

bmw-not-found

So he searched in the manuals for the parking module. And this is what he found when he accessed the trunk:

 

The trunk, accessing the parking modules
The trunk, accessing the parking modules

It probably should look like a small pool, should it?

mmm... a disturbing amount of water
mmm… a disturbing amount of water

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How to fix a bricked Chinese UC40 projector

A friend of mine was enjoying his Chinese UC40 projector, but for some strange reason, the manufacturer figured that it would be a nice feature to watermark the projected image

A watermark in your projected image… not great

So when he encountered a supposed update for his projector (which was hosted on Facebook),  which made the watermark optional, he took a leap of faith…. and was disappointed,  the watermark was gone, but also the rest of his projector functionality, he bricked it.

So he inquired as to what his options where, grabbed some beer, and started googling like mad-men.

We assumed there where two possible reasons as to why the projector didn’t function anymore:

  1. The firmware was in contrast to it’s description, not meant for this hardware
  2. The projector failed to flash the file  into his flash properly

So we started prying open the case to look for the components that may give some hints, as to how to revert to a working device

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Getting STM32 STlink V2 running with OpenSTm32 IDE and OPENOCD

Some time ago I needed bit more power that the regular Arduino is able to provide. Therefore I thought, lets brush up my ARM skills.

So I desired to make some hefty investments in ARM, here is what i got:

  • STM32F103CTB dev board, $4,88
  • ST LINK-v2 (clone), $4,08

STM32f103C8T6ST LINk -v2

This was a major sad back, not taking in consideration the poor EUR -> $ ratio 🙂

NO but searilously cheap, just the way any duch-guy likes it 😛

 

Then it is time to fire up the IDE, many to choose from, I chose: OpenSTM32 (which is basically a pre-setup Eclipse environment).

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Fixing poping noise on TP-link tl-wr703n router

I bought one of those fabulously cheap router (the TP-link Tl-wr703n) for a whopping $21,- on ebay, it comes pre-loaded with Chinese firmware.. As my mandarin is quite rusty, I decided to flash openwrt on it (read, this is THE reason to buy those little devices).

I wanted te make an audio-player of it.

First I installed Shairport on it, via this nice tutorial: Shairport+wr703N  which is a nice how-to to build your own image.

Unfortunately after flashing the device… it was dead, turns out.. I flashed the wrong image :S, as the web interface refused to write flash the by-me presented image, I did it the hardware, so flashing using “`mtd write image.bin firmware“` which bricked it… So I had to solder within 5 minutes the mailman passed me the package.. bummer :), luckily my soldering iron is always standby.

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Low-tech Laser-scanner on ARM and Harddrive motors

As I was always into Laser(s) (‘we call it a Laser’)

In an attempt to build my own laser-scanner/project i’ve googled alot… which is kinda what most it’ers do when solving stuff.

Anyhow most of the people that are into lasers and shit, are know with Elm-Chan’s project, which basically means buidling your own galvanometers and analog drivers. Since my litte appartment didn’t came with a broad set of vertical drills, milling machines and lathe’s to craft the stators of the galvano’s… I didn’t bother trying it. Another difficulty is my somehow limited analog electronics skillset… (but hey, if your writing ruby/java and mongodb queries all day..). Anyway. Chan’s path was not mine to take.

One-axis-harddrive-arm-actuator

Continue reading Low-tech Laser-scanner on ARM and Harddrive motors