PIC Digital Frequency Meter -PCBs

[Pamphonica]

As an add-on to an elderly Sig Gen, this sort of device can be invaluable.
I am thinking of it as a constructional project for the local amateur radio club (Burnham Beeches).
The problem is that it ideally needs some small PCBs made up (about 6, I should think).
The version I want to follow is this one:
http://homepage.eircom.net/~ei9gq/counter.html
Is there anyone who can do me a few small PCBs (costs refunded of course) to help out.
(I used to do my own but no longer have the bits and pieces to do so)
The club members are not very well heeled so cost is pretty important on these club projects.
The total cost needs to be £10-£12 including components.
Any help at all (or suggestions) gratefully received.
best regards
Jeremy

[Ed_Dinning]

Hi Jeremy, If you look at the Likes of Elektor and similar mags you will often see companies advertising PCB services. They have free software so you can design your own and they then product and return within a few days.
Veroboard will probably not be a good idea for this project because of the frequencies involved.

If this circuit was from a mag, it might be worth contacting them to see if they have/ ever did PCBs.

As an alternative RS used to do frequency meter modules quite cheaply; it was even possible to programme IF offsets into the readout.

Ed

[Paul Stenning]

Many of the professional PCB manufacturers will make small batches, however the tooling costs (photoplots and drilling tapes) obviously make it more expensive per board. It is worth seeing if there is a localish supplier as they may be a bit more amenable if you go and see them, explain that it is for an amateur radio club and is not urgent.

I have seen good comments about this company http://www.pcb-pool.com/ppuk/ but have never used them. They work by making batches of several different boards together to share the tooling costs. The drawback though is that the next order is no cheaper whereas with conventional suppliers the tooling is retained for further orders.

[Pamphonica]

Hi Ed,
I had actually discounted Veroboard, not realistic at 50MHz! I looked at PCB-Pool but lack of original artwork and cost made this a back-up only. (Although they can turn out 100 cm squared of board to your spec for just 25 Euro). It was a RadCom "homebrew" project hence no PCBs from RadCom, but I have tried to contact the author to see what might be available.
I think I will persist with a homebrew approach - it's a good learning tool for the club members. Modules would probably work well but I doubt if RS can turn a DFM out for £12!
If you have a recent Elector, I would very much appreciate the contact details for any other prototype PCB companies in case that proves cost effective.
If not, I shall just have to invest in some ferric chloride (etc etc)...
regards
Jeremy

[Pamphonica]

Paul,
Actually, I can happily do drilling - it's the etching I don't have the capability to do.
Ideally I would like to find someone who can just etch me a few boards.
I have versions of the (very simple) layout as a print file in .png, .pdf and .ps formats (all full size) but not the original file (orcad, gerber etc).
Even a crude pcb would help, but easier said than done, unfortunately.
regards
Jeremy

[GMB]

My wife makes prototype PCBS for me so she might be persuaded to do it for you next time she is making boards, especially if you do your own drilling. She also does PCB designs if needed.

I also have software that I wrote many years ago that will convert bitmap images into Gerber plots.

[Pamphonica]

That is an incredibly kind offer. I don't want to impose, but it would be extraordinarily useful if I can get a few etched.
The timescale is very easy - I only expect to start this project in September/October.
To make things easy, I will produce a layout with 6-10 boards on a sheet. I will guillotine and drill individual boards.
If this looks possible, I will PM you and discuss details. Very happy of course to cover any expenses.
Meanwhile I will get on with laying out my own board so I get exactly what I want. (The Radcom one is very cramped!).
best regards
Jeremy

[Jack Spark]

Jeremy, I'm planning on making up a batch of PCBs in the next few weeks. No problem to do yours too if you only want a few. To be honest, I want to use up the etch as I don't like it hanging around and Mrs Spark hasn't spotted it, yet.

Slightly off topic, but does anyone still make their own PCBs nowadays?

Anyway, let me know either way.

Cheers

J

[Pamphonica]

Jack,
will send you a PM shortly
tnx
Jeremy

[XTC]

Originally Posted by Jack Spark

Slightly off topic, but does anyone still make their own PCBs nowadays?

I make PCBs from time to time. You can still get the ferric chloride and the boards so there must be a surprising number making their own PCBs still.

Back on topic, if Jeremy has found a way to get his boards made up, that's fine, and Veroboard isn't much good at RF. Plain matrix board is better but not really suitable for microcontroller projects because of the volume of connections. Wire wrap works pretty well at highish frequencies. Making a PCB doesn't magic away the problems, you may have to debug the layout. An earthed plane gets rid of a lot of the problems - at the cost of complicating the board.

I've seen some amateur HF/VHF projects done on plain copper board with the copper side earthed and the component connections made with wire on the other side. Messy and ugly, and really only suitable for fairly simple circuits, but with a PIC controlled project like this, most of the circuit is logic connections to the keyboard and display, not running very fast, and the high frequency circuitry can be isolated on a separate board.

Pete.

[Pamphonica]

I have spoken to the author of this project and he informed me that some people have used veroboard with success, but I assume that they will have removed all unwanted tracks, not just drilled out breaks at hole sites.
I have had a great time trying out the schematic and PCB software (free) from http://www.expresspcb.com. It's easy to use (not automated, but very flexible).
I will report back once I have PCBs back from the kindly volunteers.
An important lesson they have passed on is to make sure tracks and pads are not too small.
If it all works out well I am happy to pass on PCB designs for others to use, once the club has had a chance to do the debugging!
regards
Jeremy

[theoldtrout]

I often make my own basic PCBs for prototypes and projects. Once I’ve worked out the layout on drafting film, use a sharp point to transfer the component hole positions to the copper side, then ‘join the dots’ with a PCB resist pen or dry marker pen. Dip in warm ferric chloride until etched. Clean off resist. Double side boards require accurate alignment to ensure the pads line up.

Ferric chloride is available from RS, Farnell, CPC – even Maplin sell it.

I have also tried using a computer PCB layout programme to print using inkjet or laser onto drafting film and then use this on photo-resist coated board; expose to UV and etch. The results are good but I never seem to have the time to use it. The programme I’ve used is called Diptrace: http://www.diptrace.com/ there is a free version.

Go on, give it a go.

[Pamphonica]

Thanks for all the inputs on PCB etching. I have this feeling that at some point in the future I will just have to get out my 20-year old etching bits and pieces and see if I remember what to do.
I used all the main methods all those years ago (and Mega are still in business I see, for etching supplies). I found join-the-dots fine for very small 1-offs, but tedious for bigger or more fine-detail stuff. Although in 1978 I laid out a 32Kb (yes kilobyte!) RAM board with 16 RAM chips plus interface chips, all by hand on a Europbard with a resist pen. Labour of love...
The photo method was fine, but I have no idea where I've put my UV box.
I have not tried "Stick-n-peel", but it sounds a useful way to get complex one-off boards done.
For now I will be glad to accept the kind offers of etching help. But who knows, I might get etching again sometime....
rgds
Jeremy

[Sean Williams]

Ive tried the press and peel stuff - seemed hellishly expensive for mediocre results.

The problem seems to be that getting a decent build up of toner on the film, and then getting the etch resist to stay on the board!

By far the best method I have used is the UV box and transparancy method.

I am fairly fortunate that there is a local company that will do boards for me if I send them a decent film.

Cheers
Sean

[Telleadict]

Hello

Here's a rather late contribution. I knew when i first saw this thread that I'd seen the site in the link but couln't remember where but have now rediscovered it. Hope it might be of some use to someone.

Link to DIY PCB http://www.5bears.com/pcb.htm