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23/05/2020

Flashing a HM-10 (CC254X) Bluetooth Module from OSX with an ESP8266 NodeMCU

I recently experimented with a HM-10 Bluetooth Module and Tasmota, and the advice is to flash the module to with a native CC2541 Binary (V707 at the time of writing) to ensure proper operation.

The official Tasmota documentation includes a link to a repo that includes the source for an ESP8266 and a windows application. The sources for OSX but there's no pre-compiled application or instructions. I'm lazy, too lazy to even grab my Windows laptop, so I figured out how to do it with OSX.

HM-10 Bluetooth Module

13/04/2020

The Poor Mans Spectrum Analyser - Spektrum

Over a year ago I bought a Nooelec Ham It Up Plus Upconverter to use as both as an Upconverter and as a wideband noise source, and an RF bridge, also known as a Return Loss or VSWR Bridge, with the intention of combining them with an RTL-SDR to create a poor mans spectrum analyser.

Now we're unable to leave the house for all but "essential trips" I've had more time to play with radio toys so I got the kit out to experiment with, and tested a couple of filters and antennas to see if it was viable.

The VSWR Bridge

05/04/2020

Nooelec Ham It Up Plus - Receiving High Frequency Amateur Radio Using a Laptop

The Nooelec Ham It Up Plus Upconverter takes a radio signal and converts lower frequencies into higher ones. In the case of the Ham It Up, all frequencies are increased by 125MHz, pushing the 0 - 30 MHz Amateur HF bands into the 25MHz - 1750MHz receiver range of an RTL-SDR Software Defined Radio. This allows you to listen to Amateur Radio on your laptop.

It isn't a new device, in fact I've owned it for over a year and not got around to playing with it. But this weekend I had a spare hour to give it a go and was quite surprised when I heard a German station calling CQ.

NooElec Ham It Up Upconverter and Nesdr SMArt RTL-SDR

29/03/2020

Amazon Fire Sticks not connecting to Ubiquiti Unifi Access Points - Fixed

I recently got fed up with the occasional issue with my Mikrotik Access Point so I purchased a Unifi UAP-AC-LR to replace it. I took the opportunity to change the SSID and PSK as I've been meaning to do it for several years, so I went around the house reconfiguring various devices. I got as far as my Amazon Fire Stick and although it could see the network, it would fail when attempting to connect.

Fortunately I was able to find a solution.






24/12/2019

Zigbee Interoperability with Xiaomi Devices

Standards are great. Accept when they're not. The word on the internet is certain Zigbee devices have interoperability issues with other Xiaomi Zigbee devices. I've not come against any issues yet. Maybe it's be user error, bad luck, or butt hurt Z-Wave users justifying why they've spent a small fortune on devices, or maybe it's true.

Either way, Wwalltt posed a compatibility list on Reddit, so I'm going to mirror it here for posterity.



19/12/2019

Flashing a CC2530 + CC2591 Zigbee Module with a Raspberry Pi

I've recently been adding various Zigbee based sensors and bulbs to my Smart Home setup. I use a CC2531 with External Antenna and performance has always been adequate but I'd like to extend the range to my letter box so I can receive notifications when I receive post.

After some brief research I came across the CC2530 + CC2591 Module - similar to the CC2531 but with a built in amplifier to improve signal strength / reception.

CC2530 + CC2591 Zigbee Module 
This blog post will just cover the basics of connecting the Zigbee Module to the Raspberry Pi prior to flashing. For more detailed information on the flashing process, please see my previous blog post on Flashing a CC2531 Zigbee Module with a Raspberry Pi (Remember you will to download and flash the correct binary for the CC2530 + CC2591)


12/11/2019

Can you use an ESP32-CAM module like a standard ESP32?

I've recently been experimenting with detecting if my flat is occupied using Bluetooth Low Energy (BLE) Trackers attached to my wife and I's keys in order to trigger various smart home "scenes". There's been trials and tribulations, but after trying various methods I've managed to get arrival detection down to pretty much instantaneous, and detecting someone leaving to below than 60 seconds, which I'm pretty happy with. After initially trying to do the detection with a Raspberry Pi, I quickly moved onto to an ESP32 based solution as the software on the Pi would frequently crash.

One thing I discovered fairly early on was now and then a BLE tracker would "disappear" for a brief period, usually a minute or two. I wasn't able to figure out the cause but put it down to interference or a collision, but the work around was to have multiple ESP32s receiving the beacons and aggregate the results. For my modest flat I'm currently using 3, although I could probably get away with 2.

A recent update to the ESPHome BLE Tracker has significantly reduced these disappearances but they still happen now and then. In a bid to eliminate them all together, I started to wonder if an external antenna would improve reliability. After looking around online it became apparent only a small number of ESP32 dev modules had an antenna connector, and they were hard to come by and fairly expensive.

But wait... what are these ESP32-CAM things? They're cheap, readily available and have an antenna connector which can be selected by switching the 0 ohm resistor to the second position. I bought one without doing much research (obviously) and it turned up last week.

ESP32-CAM Module
Anyway, I digress. I should really cover the BLE detection in another blog post so watch this space. If you want to find out if the ESP32-CAM can be used like a standard ESP32, click read more...