Make the ESP8266 talk 9600 baud

Monday 2017-01-02

Surprise videoThe 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.

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Seeed ESP8266 WiFi Breakout Board Pinout

Sunday 2017-01-01
WiFi Serial Transceiver Module Breakout Board w& ESP8266 pinout

WiFi Serial Transceiver Module Breakout Board w& ESP8266 pinout

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.


Designing a Fox-hunt antenna

Sunday 2016-06-19

3d radiation patternMany years ago, I used to do some radio fox hunting with cars. Usually these hunts are at night to make it more exciting, and can be great fun. As I got older I lost interest and moved on to other things. But last year, I decided to have a go at a popular balloon fox hunt on 144MHz. This is quite a large scale and professionally organized fox hunt by Dutch Radio Amateurs. Read the rest of this entry »


Measuring Coax Length and Loss

Sunday 2015-11-01

100-1015 BNC T ConnectorEver wondered how well your 50Ω coaxial cable is working? If you have a reasonably fast oscilloscope, preferably up to 100MHz and a signal generator which can generate short bursts, you can measure not only the length of your cable, but also the return loss at a certain frequency. From that, we can learn the attenuation of the cable.

This blog post describes the classic time domain reflection measurement using the following setup:

Measuring TDR
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Better modulation for the Baofeng UV-5RA

Sunday 2015-05-10

baofeng-uv-5ra-plusUndoubtedly the Baofeng UV-5Rx delivers a lot of radio for your buck. However some models in the range have a bad reputation for the transmitted audio sounding soft and muffled.

In 2013, Remco PA3FYM obtained the schematics of the radio and devised a modification where transistor Q17 of the VOX is re-purposed as preamplifier in the microphone audio circuit. It works wonders for your radio. For people needing a bit more visual guidance, below is a walktrough of how I did this to my Baofeng UV-5RA.

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Arduino and the QVGA 2.2″ TFT SPI screen

Monday 2014-11-17

QVGA SPI 2.2" 320x240 screenI 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.

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IARU Region 1 Bandplan up to 500MHz

Sunday 2014-11-02

For some reason I have trouble finding a document which lists the complete IARU Region 1 Band Plans. To end my “can I transmit here” quests, I’ve combined the information from several resources into a usable graphical representation of all Amateur Radio bands and modes up to 500MHz. I’ve not listed bands above 500MHz, please post links to those in the comments if you have them.

Exact use of a frequency may differ in your local region, so always listen first.

IARU Region 1, Up to 500MHz