Anglers Bite Alarm

[Tricky Dicky]

Hi Guys

I have a GCSE student who is designing a bite alarm for his coursework project. The current thinking is that this will be a rod rest mounted device triggered by the rapid movement of the fishing line on a pulley or roller as a fish bites.

The input will be a sloted darlington opto-isolator through which a sloted wheel will rotate producing a series of output pulses.

The pulses are to be counted by a counter (a 4017B) and after a yet to be determined count this will eventually trigger an output such as an LED and possibly a piezzo sounder.

In order to filter out low level frequency pulses caused by ripples on the water the counter is constantly reset by a CMOS based astable set to produce short ons and long offs running roughly at 1Hz (this frequency will be fine tuned with some experimentation).

The result is that low frequency pulses never reach the trigger point before the count is reset and only much higher frequency pulses result in an alarm.

I have simulated this hardware solution and it works but it is already a two IC solution and that is before the final driver stage of either a latch or monostable is added to drive the final output LED or piezzo. From past experience this looks like the PCB is going to be much larger than would be ideal.

I feel sure a much simpler solution exists using PICAXE but the code has got me stumped. So I am looking for ideas. If it helps we have PICAXE 08Ms, 18's, 18A's, 18X's and 28's available, so knock yourselves out!

Richard

 

 

[Fowkc]

Sounds like your electronics knowledge is pretty good, so it's just PICAXE specifics you need to work on.

Do you have any experience programming at all? That will help, although it's pretty easy to pick up the BASIC type language.

If you haven't used the PICAXE before, I'd start by programming an 08M to flash an LED on and off then build up to more complex things (look in the PDF files that come with the programming editor). It might be tedious, but it's the best way to learn. You should be able to progress pretty quickly given your level of knowledge.

For your application, I would think that the COUNT command would be a possible solution. It counts the number of LOW-HIGH rising edges in a certain period of time. Again, look in the PDF file for details.

 

[Technical]

count is a good bet, in fact the simplest program may only be four or five lines long!

main:
count 1,250,w1
if w1 > 500 then alarm
goto main

alarm:
high 4
stop

 

[Jeremy Leach]

I agree with using the count command. (another solution could use an additional LM331 chip as a frequency to voltage converter and feed an ADC input, but then what's the point if count works).

Here's another thought though (and hopefully haven't misunderstood your system):

Using count and a single optical sensor isn't going to give any directional information about the movement of the slotted wheel. You'll be counting slot changes but not the direction of movement of the slots.

This initally sounds ok, because all you want to know is if the line has rapidly moved. However if there are ripples (say large ripples from the wake of a passing boat) you could get false alarms because of quite large oscillations of the wheel.

With <i>two </i> sensors on the wheel you could then (with more complex code) get directional information. The count would be incremented or decremented depending on direction. You could then determine the movement for certain and eliminate false alarms.

 

[Rickharris]

Somehow I think even the most somnambulistic fisherman would notice the passing of a motor boat and relate the rod alarm to that event without software help.

Sometimes I think we softwarey types overcomplicate things because we can (OK I do it too) <img src="smile.gif" width=15 height=15 align=middle>

 

[moxhamj]

It's the Count here and I agree that counting is the way to go! Technical's code is so simple that you wonder that is all it is, but picaxes make things simple. The speed of a fish swimming away is going to be much greater than the total movement from waves.
Maybe that set point could be variable. Eg add a pot, add readadc w2 and replace the line 'if w1&gt;500' with 'if w1&gt;w2'. Then the fisherman has a bit more control over things.

 

[bgrabowski]

The use of both a buzzer and an LED is recommended. The buzzer should sound only when the line roller is actually moving. To switch it on continuously after the slightest twitch on the line would be assuming that all bites instantly need to be struck. This is not the case and the angler needs to watch the bite develop and decide when to strike.

A LED which latches on for say 5 sec after the slightest movement of the roller is desirable with the above set-up. The angler may be distracted when a very short tug on the line occurs and will be able to confirm that the line has moved visually. This is also important for multiple rod fishing for carp which is often carried out in the dark. Several bite alarms can have different sounder notes and LED colours. Indeed with the LED colours can be made adjustable by the user with a potentiometer connected to an analogue input and an RGB LED output.

 

[Fowkc]

Has anyone else noticed that this is the teacher posting on the student's behalf?

I only ask because I've only just noticed myself, and we all know that it's important to know who we're speaking to!

 

[Jeremy Leach]

Yes, I'm sure you're right Rick - except if the alarm triggered an automated mobile SMS alert message sent to the Fisherman with his feet up in the local caf <img src="wink.gif" width=15 height=15 align=middle>.

Start simple with Technical's idea ...

Edited by - jeremy leach on 26/01/2007 07:08:25

 

[Rickharris]

OK Jeremy <img src="smile.gif" width=15 height=15 align=middle> - you can tell I don't fish.

 

[Dippy]

Its not very wise to be somnambulistic next to water.

How about a bell on the end?

 

[Tricky Dicky]

Hi all again!

Just to like to say thanks for all the suggestions and help. Today has seen one of those &quot;kick yourself in the butt&quot; momments as I realised that after 5 years of using PICAXE in student projects, I have been trying to write a piece of code for which a perfectly good command already exists and only required a bit of RTFM.

The count command is the answer. I have already simulated the code and cannot believe how simple the solution is. Thanks to Rev-Ed for compiling the command.

On behalf of my student I thank you for your help. With time pressing I will encourage him towards the &quot;simple&quot; solution. The suggestions for further developing the project should prove useful to him in his project evaluation and should he use them then I will ensure he acknowledges his sources of information.

I noted Fowkc's second post and would like to assure him I am the student's teacher and openly stated that in my posting, there is no hidden agenda. The implication I take it was why did the student not post a request himself? My students range from the &quot;leave me to it, I will sort it out myself!&quot; through to the shy and most sadly the &quot;I can't be bovvered ....!!&quot;. The type of student that has posted on this forum, and I am thinking of the likes of annoyin_kid, are to be commended for having the bottle to post messages and engage in dialogue. Furthermore, you regulars are equally to be commended for your patient and tolerant replies to messages which are sometimes a little incoherrant.

My students have already made extensive use of the vast store of information on this site in their research. In choosing to go down the PICAXE route to teach students about PICs this vast free resource was the deciding factor for me and as long as Rev-Ed maintains this position I will happily spend my budget here and give my support. Coming back to my students, the forum is not barred to them, they are encouraged to seek help on their own. However, the old adage &quot; You can lead a horse to ......&quot; applies. As user friendly as this forum is, it can be intimidating to many 16 year olds to communicate with adults who they are not familiar with.

Wow! this has become some epistle, move over St. Paul. So I would like to say thanks again, keep up the good work and hopefully I will be able to let you know how things turn out with the project in May or June.

To any other teachers who use this site and wish to share ideas/projects etc. please feel free to contact me.

Richard



 

 

[Rickharris]

I am happy to share ideas we use in class. Are you teaching systems and control?

 

[Tricky Dicky]

Hi Rick

No, I teach Electronic Products. My students sit the AQA exam.

 

 

[Rickharris]

Used to teach that but went to AQA systems and control and now product design although we still do picaxe based projects in product design - where do you teach

 

[Tricky Dicky]

North Manchester. We looked at systems and control and concluded we were not really set up for it. Just about doing the Electronic Products again our setup is not ideal.


 

 

[Rickharris]

I am in Lincolnshire - It cost us about &#163;500 initially to set up for systems and control. The course was well subscribed as well.

Email me rickharris@supanet.com so we don't clog up the forum with education speak <img src="smile.gif" width=15 height=15 align=middle>

 

[Fowkc]

&quot;I noted Fowkc's second post and would like to assure him I am the student's teacher and openly stated that in my posting, there is no hidden agenda. The implication I take it was why did the student not post a request himself? &quot;

No, I only meant that had I read your post mroe carefully and realised you were a teacher, I wouldn't have made the post quite so simplistic.

 

[Tricky Dicky]

No offence taken Fowkc, I appreciate it can be difficult to pitch the level of response when you have limited information to go on.

I have to admit reading some of the posts by Hippy, Dippy, Dr_Acula and crew some of the stuff goes completely over my head but it does not stop me reading the interaction and absorbing the odd pearl of wisdom. After all in my business you have to believe in life-long learning.