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[AlanP]

I am making the ramp on my Graemsay operational, well the prototype works OK on the bench  . I also have a piezo buzzer that gives about the right sound on 4 volts, but I would like it to be like the sound that you get when a vehicle is reversing, intermittent if that is the right word.  I could probably do it mechanically but I don't think it would be quite right, so I was wondering if there is something that I could put in series with it that would give the sound I am after without going down the road of building electronic circuits.

Any other thoughts on this would be welcomed

Alan 

[boatmadman]

Alan,

You need something like an on/off timer so you can set the time duration to suit.

Ian

[AlanP]

Oh, come on Ian, don't tease me, the only timer I know is the one that makes my garden lights go on and off and there isn't enough room for one of them 

Alan

[wombat]

ACTion P73 flasher perhaps - drive the Piezo like a bulb - should give you a pulsed alarm.

Wom

[Spyderman_uk]

I don't know what an Action P73 flasher is, so I may be repeating what is already said!
I would go for a car or motorbike indicator flasher. Cheap and cheerful! Add a suitable resistor, or even a bulb, after the flasher to to get flash rate to where you want it.
You can get flashing LEDs, but I am not sure if one of those would pulse the current enough for your buzzer to sound right.

[Faraday's Cage]

Don't know if this would work but if you connect a normal led in series with a flashing led then both leds will flash.

If you connected the sounder in series with a flashing led then would you get a pulsing sound from the piezo ?

I havent got the components required to hand or else I would test my theory.

FC


(Looks like Spyderman_uk pipped me at the post)

[Shipmate60]

Some toy trucks have all the sounds and lights and operated by a simple on/off switch.
Roys-R-Us here you come!!

Bob

[OMK]

AlanP, unless you've discovered some hitherto unknown way of pulsing your piezo, apart from doing it mechanically or electronically, then what other options are there? Sounds like you're a bit worried about taking the electronics route, but, in all fairness it probably is the easiest way in this case.
Action's P73 would do what you're looking for. Alternatively, a simple two-transistor oscillator built on a scrap of stripboard would do the job. You could probably shoehorn the whole caboodle on a board measuring not much more than 25mm square. Also, of course, the ubiquitous 555 timer chip might be worth looking into.
What do you have in mind if you want to do it mechanically? Some sort of servo-operated lash-up, maybe?

Hey, Terry's Cage. How you doing, amigo?
I like your way of thinking. The LED-in-series dodge would probably work. It depends on how much current the piezo unit draws, but should be okay if'n it's just a handful of mA. Don't forget - those el-cheapo wallwart transformers employ the same simple method when they're used for recharging batteries.
A flashing LED in series with a bog-standard LED probably wouldn't work. Flasher LEDs have a built-in circuit (crammed inside the LED itself), so once power is applied the non-flashing LED will stay on all the time anyway.
Like you, I've not put this into practice, but all the theorum says it's a no-go.

[John W E]

Hi Alanp
This may help you
The circuit is from a old Radio shack book ,and is easy built on a scrap of strip board

john e
bluebird

[OMK]

Way to go, Bloobs - that little circuit will do it. And swapping out R3 for a 47K linear pot' will also let you adjust the pitch.
Trouble is, AlanP says he don't wanna go the electronic route, so we're probably punching thin air here. But if he ask's nicely, there's a chance a certain Geordie lad will build it for him, eh?

Did you not get that package I sent a couple months ago?

[John W E]

PMK I have not received any package at all from your goodself.   I will PM you later on today - hope you are well.

aye
john e
bluebird

[Faraday's Cage]

A flashing LED in series with a bog-standard LED probably wouldn't work. Flasher LEDs have a built-in circuit (crammed inside the LED itself), so once power is applied the non-flashing LED will stay on all the time anyway.
Like you, I've not put this into practice, but all the theorum says it's a no-go.

PMK,
Hey dude, I was hoping that you'de chip in with your two penneth. 
The flashing led and normal led in series thingy does flash both leds. Dont ask me how this works but it does. I was told about it by a railway guy some years ago. Saved a fortune on flashing leds.   Only problem was that they all flash at same time and rate. I've now moved on to using PICs. Just built Ghost a traffic light system for his dirorma.
I see you found the avator that I sent you when you were laid low. Keep on rocking man. 

FC.

[OMK]

Yeah, that animated GIF was just what the doctor ordered. Just at the time when it was nigh impossible to laugh, I took one look and burst in a spontaneous fit of giggles. Best medicine of all. Thanks, mate! (even though all that giggling hurt like hell). BTW, you should see the one that Sweeper sent.

Listen, can I pick your brains for a moment?
Have a look here (scroll down to the bottom of page 18)..... http://www.esr.co.uk/Optoelectronics.PDF
I remembered I had a couple of these in the junquebox. I hooked one up to the variable PSU, via a series ammeter, and sure enough, they run from about 9v, pulling around 60mA. But when I bung another LED in series (with its appropriate limiting resistor), nothing at all happens.
Did I connect them with the wrong polarity? Nope. Did I calculate the wrong value limiting resistor? Nope. Was the non-flashing LED's limiting resistor preventing the flashing LED from flashing? Nope, because I omitted the sucker.... still no joy.
How are you connecting yours?

One other question...
I got a sneaky suspicion that some of my PMs aren't getting through. Did you receive one from me shortly after you sent the GIF?

[OMK]

Bloobs', old mate... No package??? Bummer. I sent it weeks ago.
I did reply to your get well message ages ago. Did you not receive yours, neither?

It's a glorious morning here in Gloomville - for once. A golden opportunity to play with me new Tx for a spot of flying...... Or so I thought. I've just had a call from Bridgwater hospital - sez they want to see me, like pronto.
I'll give you a holler when I get back.

[AlanP]

Thanks for all the suggestions, a friend is going to make the chirp generator for me, but in the meantime and because it was chucking it down with rain this afternoon I have solved the problem mechanically by putting a cam behind the cog, the cam works a small micro switch and thus the buzzer. Was quite pleased with myself when it worked.

Sorry about the quality of the photo, going to have to upgrade my Brownie 127 

[Faraday's Cage]

Glad to know you got things sorted Alan.

PMK,  I'm using a similar led package to yours and a bog standard led in series but leave out the limiting resistor as the electonics in the flashing led looks after the current limiting. Try on 12 volts.  Doesn't matter which is first either flashing or normal led. Connect 1 x pos and 1 x neg from each together then other ends to respective connections on battery / psu. Trust me, it works. Any probs and I'll post you the bits so you can see for yourself. 

BTW, sorry but I didn't get the PM that you mentioned before.
Hope you're on the mend.

FC

[FullLeatherJacket]

Don't know if this would work but if you connect a normal led in series with a flashing led then both leds will flash.
If you connected the sounder in series with a flashing led then would you get a pulsing sound from the piezo ?
FC

FC
Certainly does work, mate. I've got that exact set-up acting as Mains Trip Alarm on my bedside table. The mains supply is dropped to 12v DC via a plug-top regulator; this holds a 12v relay closed until the mains shuts down, when the relay drops out and the COM+NC contacts complete a separate circuit which runs a flashing LED and piezzo buzzer from a PP3 battery. All bits from junque box, as PMK would say. To date this has saved one freezer-load of scoff due to a nuisance RCD trip, and another one down to E-On's sub-station fusing (or whoever supplies our electrons this week....).
Works for me.
BTW We supply P73 to the model truckers who use it for combined flashing hazard lights and piezzo sounder, triggered by a microswitch when reversing.
Works for them, too!
FLJ

[BarryB]

Hi Faraday's Cage

Nice to hear that someone else is using PICs.

I reckon we can do (almost) anything with them for models - the only trouble is that people are scared (or do not have the time) to solder.
I have a lot of solutions (using PICs) but when people ask for them, I have to say that I only supply the PIC chip (usuallly) and don't build up the boards for them. So they retire disappointed too often.

My modelling interest is in programming the PICs for all model boats, railway, aircraft, test equip - Only building when necessary!

These thoughts were triggered after reading the first post of AlanP:
"without going down the road of building electronic circuits"

Barry

[Faraday's Cage]

Hi Barry,

Yeah, its taken me a while to get my head around PICs but using Basic programming and compiler makes things a lot easier for me to understand. I've got to the point where I can output to devices (leds, buzzers, etc) also servos now which is coming in very useful. I can input from switches, buttons and pots.  Haven't tried using rc signal inputs yet but that would be handy.  I tend to design and make my own PCB's using a standard format for the PIC circuitry and bolting on the additional stuff as required.
I'm using a Proton IDE Basic compiler and a QEL programmer from Quasar. Don't think they like Vista too much so I'm sticking with XP for now.
BTW, I've got one of your mixers and its working fine in my pusher tug.
FC

[barriew]

FC and/or BarryB

Can either of you recommend a good introduction to PIC programming?  I am quite interested in having a go. I used to be able to write Basic programs, but haven't done any for many years :)

Barrie

[BarryB]

Hi barriew
We are well off topic now, I hope we are not admonished 
But I think he original question is played out now anyway :)

I reckon the best way to learn is to start with a PIC chip, a programmer AND plenty of time!
The chips can be used over & over again.
or Everyday Practical Electronics do a course every few years.
Look at published programs in above mag etc.

I find the lessons learned from "Basic" will stand you in good stead - but I also did 6502 assembler for the Commodore range.

So programming PICs in assembler wasn't too bad.
Every step achieved is a huge reward in itself, even if only a small step.

Give it a go.
Barry

[Faraday's Cage]

Hi BarryB,

I'm using Proton Development Suite which uses Basic (which I understand) and then converts to machine code (haven't a clue :-\).
You can download a lite version at http://www.picbasic.org/proton_lite.php#download if you fancy a look.
Also available for download is the user guide from this webpage http://www.picbasic.org/proton_development_suite.php

Maplins did a good range of PIC starter books but dont know if they are still in print. Worth a look though.

FC

[wombat]

Hi Barrie,

Will try to catch up with you at the club.....

Go for the "F" series devices as they are reporgrammable. I have a PICKit development system - simple programmer, costs around £25. I also have an ICD-2 debugger but that costs a bit more unless you can bum one - £90 for the unit and about £15 per processor type.

Use Microchip's MPLab which comes with the assembler and a C compiler (albeit a limited one) that will do the baseline parts. I use C for my goodies - less legwork. There are header files for the compiler that hook you anot all the internal registers.

Useful devices  - 16F684 is pretty flexible

Wom

[OMK]

PMK,  I'm using a similar led package to yours and a bog standard led in series but leave out the limiting resistor as the electonics in the flashing led looks after the current limiting. Try on 12 volts.

I believe you, I believe you. But even when I shove 12vdc up there AND omit the non-flashing LED's limiting res' I'm still getting diddly. Although, the flashing LED works fine on its own - as does the non-flashing one.
Weird, huh?
I remember purchasing a batch of 3mm green LEDs at one time. For some reason, each of their Cathodes and Anodes were transposed. I figgered I might have run into the same problem in this case, but that isn't so.

On a slightly different subject, I see you're using PicBasic Lite (sooooo much easier than all them hex and binary digits, right?). I use it all the time now.
I got frustrated with the limited 30 lines of code on the Lite version. If you're in the same situation, gimme a holler and I'll bung you a full working copy on CD.

[Faraday's Cage]

PMK,

Thanks for the offer.  I started with PicBasic lite but have upgraded to the Proton compiler. Its like an upgraded version of PicBasic but in this case the license key is contained in a usb dongle. This means that you can put the software on any machine (up to XP) but without the dongle it wont work. (Crafty).

The flashing led I'm using is an old red flash led that blinks rather than flashes . Not tried the test with one of the newer types of flashing leds with a brighter output. That might be your problem.

FC