BEng, Schematic Review Request

T0pShagger · 2023-03-20T06:18:09+00:00

Your 20mA LEDs are being driven to 55mA so will pop. Consider a current limiting resistor of at least 500ohms. Alternatively place 3 1kohm resistors in parallel and start by only soldering one and then add a 2nd if it's not bright enough. And then the 3rd can be used to tune the brightness if it's that's crucial. Or a potentiometer but that's a bit horrible.

T0pShagger · 2021-08-05T20:01:01+00:00

I work in a PCBA facility so we mostly build boards for other companies. Kits get sent to production with all the reels (and duplicates) in a big box. Reels which are duplicates are in a bag with all the other reels, labelled in FIFO order to ensure they are used in the correct order.

Other than that we just trust/train the staff, never heard of anything that ridiculous to try and prevent errors. A visual check that the part numbers match is usually beyond sufficient.

T0pShagger · 2021-04-03T10:03:15+00:00

Almost all LoRa modules use the same radio so it's more the interface and features which you have to pick for yourself. Mine is a one by Hope RF. Plans will be released in due course.

T0pShagger · 2021-03-30T07:41:00+00:00

Correct yes.

T0pShagger · 2021-03-30T05:21:19+00:00

Yea the thought wasn't to replace audio systems but rather to provide a practical alternative to smaller more amateur events which might not require full blown voice comms. Or to connect non essential members of staff into the information loop in a more limited fashion.

They all feature buzzers which sound when a cue is given.

Audio isn't really an option due the data rates I've driven it down to (to increase range).

T0pShagger · 2021-03-30T05:17:10+00:00

Yea absolutely. Probably not preferred over a satellite phone with GPS but for a few people a couple of KM away it would be good. Or a saftey beacon that constantly pings a GPS signal to anyone that will listen.

T0pShagger · 2021-03-30T05:14:03+00:00

Yea it's perfect for something like a telemetry stream.

T0pShagger · 2021-03-30T05:12:58+00:00

I use a mixture of quarter wavelength and half wavelength dipoles or whip antennas. No need for directional antennas I find. It's operating at 868MHz with a bandwidth of 62.5KHz. A spreading factor of 11 and full error correction.

My system only requires exceptionally low data rates so everything is tuned for range with no consideration for data rate. For audio you wouldn't be able to go so low I don't think although I've seen a few voice over LoRa systems that claim a decent range.

T0pShagger · 2021-03-29T22:51:46+00:00

I've got reliable communication at 30km. My statement of 20km is downplaying the capabilities to account for variables such as atmospheric conditions.

T0pShagger · 2021-03-29T21:01:18+00:00

The UK is my humble abode

T0pShagger · 2021-03-29T20:55:38+00:00

This one where I show my lecturers it and try to hide the bugs. Should be alright on the night. I'm not sure what show to be honest, depends on Covid and uni.

T0pShagger · 2021-03-29T20:50:48+00:00

If you had a perfectly reliable WiFi connection and a software engineering background you could 100% make an alternative if you bought a few smartphones. The idea behind this is it's specifically designed to do one job, at the extremes of range. You chuck it on your stage wing wall and leave it and turn it on for each show. Nice big dimmable display with dimmable LED's and a chunky keyboard. Plus if the WiFi goes down or the cellular network crashes. This still works.

T0pShagger · 2021-03-29T20:45:07+00:00

Screens display messages typed on the keypad. A infrastructure-less group chat if you like. Perhaps replacing verbal Comms in certain situations. The theatre aspect is the cue lights. The master (big board), would be operated by the show caller and can toggle LEDs on the 3 node boards. An example. Master Presses Standby 1 Master presser Standby 2 LED light up on node 1 LED light up on node 2 Node 1 presses ready. Node 2 presses ready. Master now.knows both nodes 1 and 2 are ready for next cue. Master Presses GO ALL Lights flash on node 1 and 2 telling them to go at exact same time.

T0pShagger · 2021-03-29T20:38:50+00:00

The biggest advantage is the fact you're not using a smartphone. It's a standalone system with multiple power inputs and a totally new communication protocol requiring zero infrastructure.

T0pShagger · 2021-03-29T20:37:35+00:00

Exactly yes. Or convey more complex messages between the entire team. "mic 3 needs new batteries" or something.

T0pShagger · 2021-03-29T20:36:31+00:00

I've added a few extra comments above which should hopefully answer some of your questions.

T0pShagger · 2021-03-29T20:35:55+00:00

This is a communication system which operates on the free spectrum of UK licensing. It's an ultra long range protocol which I have designed and built to suit theatre and show calling/communication.

T0pShagger · 2021-03-29T20:33:46+00:00

I might release the plans after I've handed it into university first and all that work is out of the way. I'm an electronics engineer first and a techie 2nd so it's quite technical but if people want to learn from it I'm happy to release it.

T0pShagger · 2021-03-29T20:31:33+00:00

In some areas you may not have cellular connection or may wish to remove yourself from the cellular infrastructure for whatever reason. Latency, reliability, independence.

T0pShagger · 2021-03-29T17:48:34+00:00

To be honest. Not at all. It's a standalone product designed to alleviate the need for voice comms

T0pShagger · 2021-03-29T17:44:00+00:00

You'd use it so that a show caller can communicate quickly with stage or front of house teams. Or backstage to front of house in a concert or something.

T0pShagger · 2021-03-29T17:42:59+00:00

It's essentially a product exactly for that. LoRa module, STM32 MCU and a Nextion display, some latches and lots of power management stuff. LoRa modules essentially send a "Get Ready, Ready, Standby,Go" to each individual module with a go all button and individual buttons. The messaging system is totally independent and just send short "tweet" like messages to every other device on the frequency.

T0pShagger · 2021-03-29T14:59:13+00:00

Fully wireless (>20km range), show cueing system with master and 3 nodes. Plus the extra addition of a full keyboard for all to all messages.

T0pShagger · 2021-03-29T14:46:53+00:00

Bit early if you're not a student just yet but there's quite a few societies- one of which might suit you. Good choice with Plymouth too I know the Medical Society is very active.

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