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hpr2173 :: Driving a Blinkt! as an IoT device

I have a Raspberry Pi Zero with a Blinkt! 8-LED array I'm setting up as a notification device

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Hosted by Dave Morriss on 2016-11-30 is flagged as Explicit and is released under a CC-BY-SA license.
Raspberry Pi, Blinkt!, BlinkStick, MQTT, Mosquitto. 6.
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Duration: 00:39:09


Driving a Blinkt! as an IoT device


I managed to buy a Raspberry Pi Zero when they first came out in December 2015. This was not easy since they were very scarce. I also bought a first-generation case from Pimoroni and some 40-pin headers. With the Zero this header is not pre-installed and it’s necessary to solder it onto the Pi yourself.

I have had various project ideas for this Pi Zero, but had not decided on one until recently. Within the last month or two Pimoroni produced a device called the Blinkt! which has eight APA102 RGB LEDs and attaches to the GPIO header. This costs £5, just a little more than the Zero itself.

My plan was to combine the two and turn them into a status indicator for various things going on that needed my attention.

Long notes

I have written out a moderately long set of notes for this episode and these are available here


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Comment #1 posted on 2016-12-01 14:27:42 by Jonathan Kulp

You light up your life

I'm posting this comment with the sole purpose of turning Dave's light on. :) Super cool episode Dave! One of these days I'll use the IO pins on one of my Pis. I have an LED-related episode in mind too, though a very different kind. Once the semester is over I'll stop just lurking and post a new episode. Thanks for a great show.

Comment #2 posted on 2016-12-01 14:45:20 by Dave Morriss

It worked!!

Thanks Jon,

As someone who studied Operant Conditioning back in my university days I am rather aware that I might have constructed a means of conditioning my own behaviour! I should work on a food reward dispenser system of some kind perhaps.

Looking forward to hearing about your LED project at some point too :-)

Comment #3 posted on 2016-12-03 14:57:32 by Mike Ray

Twinkly Lights and MQTT

Terrific show Dave.

I had never heard of MQTT until I heard this show. I was looking for an alternative to a XMLRPC client/server solution for a commercial project I am working on, and I have done work in the past for a company that makes communication gear for French metro operators. I note with interest that MQTT conforms to Cenelec standards and is already used by some railway hardware manufacturers.

I'm going to set my alarm clock for the middle of the night now just to post comments so that your little twinkly lights are on when you wander into your den in the morning :-)

Comment #4 posted on 2016-12-03 15:49:42 by Dave Morriss

Re: Twinkly Lights and MQTT

Cheers Mike,

Yes, MQTT is really cool and quite simple.

When I was working I did look at SOAP and XMLPRC as possible ways of shifting data between systems for account provisioning purposes, but never implemented anything. MQTT might well have been able to do what we wanted.

It'd be interesting if you could tell us more about the sort of applications you have in mind for it.

It's always cheering to find the comment notification light on when I get up, so go right ahead :-)

Comment #5 posted on 2016-12-03 18:33:48 by Mike Ray

MQTT and hardware monitoring

Hello Dave. I can't say a lot in detail but I've worked before on desktop client software which monitors the telemetry served up by microcontrollers embedded in communication equipment used by French Metro systems. It all stems from an overhaul of comms equipment that happened after the Mont Blanc tunnel fire highlighted that the systems used by all three emergency services involved could not communicate with each other.

The original protocol we developed was bespoke, but since the explosion in IOT and other such things customers are now much more fussy about the protocols in use and having them meet standards.

A lot of folks are trying to stretch the point with SNMP, especially version 3 since it supports encryption, but in my opinion this is an incorrect use of the protocol which is designed to do exactly what it says on the tin, manage networks.

Since MQTT already has found use in railway systems and complies with Cenelec we may be able to pursuade customers to abandon their misuse of SNMP and adopt MQTT

Comment #6 posted on 2016-12-04 20:00:52 by Dave Morriss

MQTT uses

Thanks Mike,

Interesting project. I don't know that MQTT provides a great deal of security itself. There is authentication built in but the documentation seems to suggest using TLS or VPNs for the security of messages.

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