Building a receiver for a voice repeater system in this area I set up a thumbsat receiver connected to a Raspberry Pi. The receiver is part of the repeater system to widen it’s receiving range. However, the performance turned out not to be too optimal. I guessed that the GSM and Wifi signals around here could cause the RTL2832U to overload, so I decided to build an intedigital bandpassfilter using Ajarn Changpuak‘s excelent interdigital bandpass filter calculator.
The default serial speed on the ESP8266 WiFi chip is 115200 baud. If you connect this chip to an Arduino and want to use SoftSerial to talk to it, it will not work. The SoftSerial library is limited to 9600 baud because of hardware limitations of the Arduino. If you want to talk to the ESP8266 with an Arduino at lower speeds, you need to tell the ESP8266 to slow down.
This is the pinout for the Seeed WiFi ESP8266 breakout board. Please be careful, it only accepts 3.3 Volt nominal input voltage and logic. Putting 5 Volts on any of the pins may permanently damage the chip.
The ESP8266 on this board is programmed to do serial communications at 115.2 kilobaud, and accepts AT commands.
I went through all the struggles everybody else seems to be going through to get this screen connected to my Arduino Nano. I had the 5V to 3.3V voltage conversion problem, and the “only works with software interrupts” problem which makes the display run slow. The solutions are not complicated but not very wel documented. Until now.
I recently needed to print out a big schematic diagram of the RX/TX board of a Kenwood TS50 Transceiver. This did not fit on a single piece of paper. Instead of downloading all kinds of crappy tools or uploading the image to some “free” site which is going to use it for whatever they think justifies their definition of “free”, I found out you can do this in Excel. Here’s how:
- Make sure the image you want to print out as a poster has a decent resolution
- Open Excel (maybe this will work in LibreOffice too, I haven’t tested, let me know)
- Drag the image into a new worksheet so that it is top-left of the sheet.
- Open the “Print preview” (the little icon in the bottom left of the window)
- Resize the image so that it covers more than one page, up to the number of pages you’d like the poster to be. Your screen should now look somewhat like this:
- Optional: Adjust the page margins.
After this, you’ll be gluing the pages together, but I think you already figured that out beforehand.
After reading my last blogpost on Anonimatron, you must have asked yourself “Great, but how do I actually use Anonimatron to de-personalize my database”? I tried my best to make basic Anonimatron configuration as self-explanatory as possible, just start it without any command line arguments and it will tell you.
Less adventurous or in a big hurry? This blogpost will show how simple it is to install and configure Anonimatron on an example MySQL database.
Since the interview of Edward Snowden with the Guardian, the discussion about privacy and companies storing and sharing unencrypted private data is picking up. Particularly Americans are worried about what it does for their National security and their private data. But that’s actually a naive thought, given the NSA stores worldwide data.
In a recent coverage on theblaze.com (a rather tabloid-looking news station in the U.S.), the interviewers are shocked to see that the NSA spies on “every American”.
This is a limited view of the world and failing to see the importance of spying on people outside the U.S., but lets start with technical side of things first. What data are they storing and how big is their hard-disk?