It might not be clear from my pics, but each wire lies inside its own duct (see posts 54 & 50). They can’t make contact with any other wire.
2 Likes
Hi John
In the short term probably not. In the long term I couldn’t say for certain. Probably a lot depends on environment as to how long bare copper takes to deteriorate. I personally would use tinned wire throughout as a thing of habit. During my working life I suppose I just got used to some very fussy customers who laid down some pretty tight specs. In almost all cases for a good reason. One almost universal spec comes to mind which stipulated “there shall be NO exposed unprotected bare metal.” This meant copper, aluminium, steel, all metals. Indeed if you used the incorrect tool on a nut or screw and damaged the plating the item had to be replaced (using the correct tool).
One article in the AWA Standard Practice Manual stated that when fitting a through hole component to a PWB (“PCB” was not used as “PCB” is a cancer causing agent in the old oil filled paper capacitors) the component lead was to be cut prior to the soldering operation. This was for 2 reasons. 1) this reduced the risk of dry solder joints caused by any heat sinking effect of the extra lead and 2) The soldering operation provided a protective film of solder covering the exposed metal of the component lead.
All the above was laid down by persons far smarter and on a substantially larger pay scale than me so let us say I just believed them and tried to make sure I did not have to do anything twice.
It just seemed a shame that after presenting a brilliant project such a little thing at the end has the potential to spoil it a bit. For me anyway but there again I might be a bit fussy.
Cheers Bob
4 Likes
I now understand.
Thanks for the background. I get a buzz from the history of technology and manufacturing. During lockdown I watched many historical youtubes about this. It seems that alot of film material has become declassified or made public especially from the WW2 period. I watched some on high reliability soldering because you raised the subject. I was inspired to have a go at making something of quality.
I understand the importance of hi standards for mass produced products that need to last a long time in unpredictable environments. The biggest weakness with my device is the plastic the housing is made of. It is PLA plastic. It softens in heat. If left on the dash in hot sun it softens and sags. It would still work, but would be an interesting shape.
There was a pragmatic reason to use stripped wire. I would prefer to use insulated hookup wire but have some work to do to make it 100% easy to work with. I’m aiming to make a design that anyone can build without a struggle. At the moment the struggle is in the assembly. I’ll get there.
Thanks to everyone who has shown an interest.
John.
2 Likes
Hi John
Might take up the shape of the dash. Stop it sliding around. Could be a marketing point.
And I am sure you will. If someone has to make it, assembly is all important. A lot of thought has to go into it. That is why manufacturing companies used to (don’t know about the present day) have model shops, the interface between design and practical production. All important.
Cheers Bob
1 Like
It would be interesting. Might look like those paintings of melting clocks Dali did.
Today’s buzzword is “UX” – User Experience.
2 Likes
I’m new to the party and might have missed something, but why dont you just use solder through enamelled wire?
I’ve used it on a load of projects and there’s no issue with them touching each other as they are insulated.
2 Likes
Hi Andrew.
I haven’t worked with enamelled wire. Looks like it would require a few extra skills.
The first design I built used insulated jumper wires or single core insulated hookup wire. The problem was the tight spaces I had for soldering to the boards. Making the wires longer alleviates that but they have to be crammed into the box when I position the boards and they push back like springs.
So now I’m trying an approach that exploits the capabilities of 3D printing. I can create tiny tubes that form ducts, or conduits, for each wire. Instead of a box with open sides, it is solid. Each duct runs from thru hole to thru hole. Wiring the boards up is easy as the wires emerge from the ducts precisely at the correct thru holes. You can’t make a mistake with the connections.
What I need to sort out is whether to use insulated or bare copper wires. It’s not always easy to insert a wire all the way thru the duct. Sometimes insulated is easier than bare and vice versa. I’ve nearly got it mastered though.
The end result is good. Each board is tight & flush against the housing. The wires are hidden and safely separated from each other.
Some pics of the finished job (and it works!):
4 Likes
Enamelled wire is no different to use, you just need to tin the ends until the enamel burns off, you’ll know when it does it kinda bubbles.
Ive used it instead of insulated wire in similar situations to you where I needed to pack a few wires into a small area, in fact I am in the middle of a new project where Im using it for the exact same reason, insulated wired wont fit.
Your solution looks good and you seem to be done, so there’s probably no need to change, it would be just giving me the willies knowing that I had uninsulated wires in there 
2 Likes
But they are insulated, just not with the original PVC. Each wire is sheathed in PLA. The only uninsulated parts are at the ends where they are soldered to the boards.
3 Likes
Hi John
Nice GPS learning exercise for me. Thanks for writing it up as a project. Lot of work getting there from you. I’m probably going to have a go at it. Just printing the monobloc at the moment to see how it goes and if ok will try threading the wires. One question I have is about powering the device. I note you are not using a logic level converter as per the recommendations on the GPS module page, I’m not sure how you get away with it with Rx connected to the 5v nano, but am I right in concluding from the sketch that Rx is never actually used even though its connected and the nano is only listening to the module on its Tx connection? I guess there is no reason to be sending the GPS module anything or am I way off track??
3 Likes
Hello Roger.
Thanks for those comments and having a go at printing the monobloc. Call out if you have any problems.
I haven’t included any logic converter and your’e right, only the GPS TX pin is used as I’m not sending any config commands to the GPS from the Nano. I’m not certain, but the board might take care of it for the GPS RX connection. It certainly allows you to use 5v power supply from the usb connection. Remember that the board is not made by ublox. The board’s maker has included a voltage regulator that supplies 3.3v to the ublox chip. You could omit the wire from GPS RX to Nano TX and the device would work just the same.
I’m looking forward to hearing how you go. Post some pics as you go.
Cheers,
John
2 Likes
Hi John
Thanks for replying. I’ve been waiting on a few parts and still waiting for my nano board which is on backorder but I have made some progress. From further reading I think you are correct about the receiver board protecting the uBlox chip, including its Rx/Tx pins from over-voltage. This is confidently stated in one online guide for the board.
I printed your monobloc and it went well. I was able to feed 0.7mm fishing nylon through all the channels and having finally got hold of some 0.5mm copper wire that I’ve confirmed goes through ok too. The GPS receiver I got from a different supplier must come from a different manufacturer because it doesn’t quite sit properly in your antenna holder. I think its about 1mm narrower and it falls through, so I think I’ll have to modify the holder slightly. I’ll do it in Rhino3D which I’m well used to, as I haven’t used Tinkercard for any design work.
In the interim I stuck the antenna to the receiver with some double sided tape across the center and it seems good and firm. I’ve got the device sitting on a breadboard with a UnoR3 and when I tested it using test sketches from the tinyGPS github site, to my surprise and delight they all worked immediately. Got a fix within seconds and found 16 satellites. It located me to within a metre or less of where I was sitting according to visualisation on google maps, and accurately measured me moving just 10 metres away to another spot. Must be beginners luck as I was expecting it to be tricky after reading about others’ experiences.
I also hooked the receiver up to u-centre directly with a TTL to USB adapter and that all worked immediately as well but only after sorting out a very weird issue with the COM port interacting and interfering with my mouse. The mouse was jumping all over the show and after initially having a GPS fix that I lost, the COM port I was using was greyed out in u-centre. Anyway, with vital help in a solution from another online forum, a simple registry edit for the mouse driver fixed it and all has been fine since. This problem seems to have been associated with FTDI TTL to USB adapters.
Unexpectedly, when I took my laptop and the receiver back inside to my desk, it continued to receive data from 6 satellites! Not sure how that works downstairs in a two storey house, but it does. Maybe the signal is sneaking in the windows, which are at least 3-4 metres away??
I put the TM1637 display through a test process and that’s working fine too, along with my peizo buzzer. Today I rigged up your circuit on a breadboard with my Arduino Uno and got your sketch to compile after adding in a couple of missing libraries (TM1637 and SoftwareSerial) but when running it, my display only shows “0”. The monitor indicates that the sketch is deriving the UTC and speed from the first two messages received but in my case these are not RMC & VTG, but are GLA and GGL (see images), so the UTC time and speed I need are not being picked up correctly. I don’t know what determines the message sequence but if this is consistent then I can recode the sketch to fit this, or maybe use the GPS library which seems pretty easy to use. Anyway, that’s where I’m up to now. I’m now just waiting on the nano so I can try to build it on your 3D print chassis. Looks like that’s probably still 10 days or so away, most of which I’ll be away from home anyway and hopefully it’ll be here when I get back.
