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Forum Index : Electronics : 12v Dc timer module SILCON CHIP MAG
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Lapsy Senior Member  Joined: 28/01/2012 Location: AustraliaPosts: 103 |
Yeah no problem. Was unsure if on this site you were "Allowed" to use html e.c.t as some try keeping it simple. Good to know for future, helps explain things with pictures easier sometimes. Just kicking back waiting for the postman now to proceed further. Scanning around for some cheap 12v DC pumps now in meantime. Suppose I could now proceed in asking about types of batteries & chargers for something like this. Could you use a car battery? I am thinking Sealed Lead Acid Hobby types easier, like - 12v 6AH SLA Another 2 things come to mind... 1. Solar panel charging a battery. 2. Charging a battery with a water dynamo of some sort. Get the water to cascade down into a waterfall type setup, running off a Dynamo water wheel type charger maybe. But probably would have to run solar to keep it going constantly, so I don't know really. Sounds cool though! Not thought about wind. Dont know much about it either! For some reason I seem to think it would be the most expensive way around. But I have no idea at all on how cheap parts would be e.c.t. Never looked into it other than seeing this 50w'er. It's a telescopic vertical axis thingy Don't really need 50w for this project. This is my signature ---> Scribble, scrawl, a bit of light pencil shading, some indelable ink and a bit of caligraphy. |
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Tinker Guru  Joined: 07/11/2007 Location: AustraliaPosts: 1904 |
You could look into 'bilge pumps' very cheap 12V DC water pumps. They have problems with pressure though, lots of flow at a low head to move water out of the bilge  - no good to squirt water over the fence  .
Maybe suitable for your needs, they need to be underwater all the time so you mount it in a container to pump water from. Klaus |
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| larny Guru Joined: 31/10/2011 Location: AustraliaPosts: 346 |
Lapsy, You wrote this in your first post (I have only just seen this thread) "Basically, I want an article from silicon chip magazine, Issue 217, October 2006" I have all of the SC mags back to 2001. So I can scan that article for you if you still need it. I did a quick scan of the posts but not in enough detail to know if you still need the article. Len |
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| Lapsy Senior Member Joined: 28/01/2012 Location: AustraliaPosts: 103 |
Tinker, Fish tank pump is submersable and there is fish so thats sorted easy and kills 2 birds. I can create air for the fish just with some decent waterfall impact instead of using an air pump/stone and I recon a solar fountain pump might do the job and keep that seperate from the timed circuit. It can run freely all day then. Eventually i'll probably try and landscape all of this into the garden, in a water feature type setup I am thinking. But thats a bit later on down the track. It will look like a science experiment in the meantime till I get things up & running. Larny, Brilliant! A scans fine. You should upload it to mediafire.com and post the address on here or message it to me. If it's on here other users can grab it if they are following this thread, or want to attempt this type of thing later. I know I'm on my L plates in regards to electronics. Anyone who knows a bit about it would probably knock this up themselves without instruction. I dare say it would still benefit people on a hobby level and gardeners also who are curious. Up to you what you want to do though...  This is my signature ---> Scribble, scrawl, a bit of light pencil shading, some indelable ink and a bit of caligraphy. |
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| larny Guru Joined: 31/10/2011 Location: AustraliaPosts: 346 |
Lapsy, I'll scan the article for you, but it will probably be tomorrow as today will be rather busy. In regard to your limitied electronics knowledge, there are various electronics forums in addition to this one, eg. electro-tech-onlne, edaboard, etc. And I'm happy to help also. Len |
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| larny Guru Joined: 31/10/2011 Location: AustraliaPosts: 346 |
Lapsy, I have up loaded the scans to media fire. I have never used it or heard of that site before, so I hope it worked. Fortunately it seems to be fool proof. The link is http://www.mediafire.com/?id0stoup84e8ske,kuwrkat90359s7n,nr 3ip531z1c9kn8,r0iugbxmnmeaur4,llxfdc4lvb04gb4 Let me know if you can't read some part(s) & I'll scan that particular section(s). If you need help with the electronic aspects, just ask. Len PS I'm puzzled as to how anyone would find anything on "media fire" as it did not ask me to put the scans in a particular file, eg. "Silicon Chip article" or something like that. |
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| Lapsy Senior Member Joined: 28/01/2012 Location: AustraliaPosts: 103 |
Thanks for that! Been busy but gathering all the parts bit by bit as needed. Was curious how they mounted it all in the plastic case. Recently digging through the spares at home, I found a nice suitable black project box/case simmilar to the one shown. So thats a plus for the situation. Haven't even used it yet, so there's another thing laying around I can recycle. I am no scrap merchant with 5 wrecks in my front yard, but do keep odd things for future use if I get any big ideas! Always salvaging computer spares mainly. Pulled many a computer case from hard rubbish and built new systems within them. It's good to be resourceful if you are not too worried about having the latest looking thing or design. Mediafire was my next best suggestion seeing as megaupload are out of action for a bit. I bet there's loads of files online, but the search engines are getting hammered for letting people source certain things. Google has been changing it's search results I have noticed recently on a few things. Guess the good old days of the internet are comming to an end. Grab what you can while you can I recon! Good to be able to view the files online if you don't want to download things like this for whatever reason on mediafire. Anyways... I shall continue on in meantime with this! Will take me a while to get the time to complete it, but I will keep you lot posted on progress. Can't wait to get this prototype going.
Another thing I should mention. For me, this is the cheapest way out for a DC timer. Like I said before, I played with a cheap chinese inverter but did not do the job as stated. Wouldn't power a water pump for some reason on it's own. My idea was to just plug a wall timer into the inverter, piggy backed by a water pump. I will note all this was running on 110v (The pump was 110v also but no go). I still have a USA timer (with USA 3 pin socket) which cost $10 delivered online. I've opened this also & it's showing a 30vdc relay in the internals. So thats up for modification also after this. I don't know if this is the cheapest way around (for me, I had the parts laying about so...) but if the timer part is the main component, for $10 plus the mod its looking pretty good to have 8-16 optional presets on a 24/7 programable DC timer. Maybe you could beat the price on that, but doubt you will get the same amount of timer programming options for the money. Would be happy for someone to point out a cheaper and more versatile way. I am open minded & can be flexible upon expansion. Only catch with this is running 24v I will have to run 2 X 12v pumps but thats 2 seperate lines I can run from one timer. My next question is what if I jacked the voltage up to 48v to run say 4 pumps? How many pumps could I run through this timer on DC voltage or does it blow the relay out or cause malfunction? Alternatly, I suppose I could opt for 4 X 6V pumps or something. I recon it's a good question to ask before I actually get the iron out and dedicate myself to this idea (although I am already neck deep in it out of pure fun and curiosity). If it can be pushed to handle more, that would be great! Less timers in the long run per set of pumps. Then I guess there's greater failure rate also if there is any issues. Automated things are fine when working, but usually no one is about to immediatly notice when they do pack up. But there are sensors and stuff I could integrate into the system for E.G Low water levels E.C.T Suggestions please? Cheers all! Great communication on this site. This is my signature ---> Scribble, scrawl, a bit of light pencil shading, some indelable ink and a bit of caligraphy. |
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| larny Guru Joined: 31/10/2011 Location: AustraliaPosts: 346 |
Do you mean that you have a 24 Volt supply and you want to connect two 12 Volt pumps in series across it? If so, I don't know how well they would run in series. Someone else may have done it and be able to comment. And what do you mean by "2 separate lines"? You also appear to be saying that you want to connect four 12 Volt pumps in series across 48 Volt. You would have to choose a relay that can switch 24 or 48 Volt & the motor current. And you need proper spike suppression so as to prevent arcing of the contacts. So if you clarify what you're wanting to do, I can advise you further. Anyway, others may be able to help also. Len |
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| Lapsy Senior Member Joined: 28/01/2012 Location: AustraliaPosts: 103 |
Ok, if you check the prior posts, we are running off a 12v power supply. Stepping up to 24V with a step up circuit. So the output from the timer will still be 24V. So basically how many pumps can I run off this timer. 1 X 24v pump. 2 X 12v pumps. 4 X 6v pumps? How many volts can I pump through this circuit to run however many pumps? Do not worry about time they probably only run for 5 min maybe twice to 3 times a day. Seperate lines - meaning pipelines E.G 2 pumps would run, 2 X 6Mtr pvc pipe (one pump per pipe) If I can get 4 pumps running of one timer E.G 4 X 6v off 24V supply pumps then I would run 4 lines. If only 2 pumps@12v each = 24v usage on 2 lines. Basically it's an attempt at keeping costs down by not having one timer per pipe. I don't really want to constantly mod timers for the rest of my life haha! The other way is to just tag another 6mtr length on the end of the first and expand that way, but then I would need faster flowing pumps which may increase the price due to the Ltr per Min rating. Still working this bit out to see whats cheaper/easier & best in the long run for expansion. The 48v thing is a question. The timer can obviously take 240v AC, but I know DC is a bit different. Curious to know what the maximum DC voltage the timer could take? I will then attempt to revolve the amount of pumps around this (Hopefully!) Hope that helps explain better. I type fast sometimes and often end up not filling out my sentances properly so sorry if if this causes a bit of confusion. I am slack on the keyboard! This is my signature ---> Scribble, scrawl, a bit of light pencil shading, some indelable ink and a bit of caligraphy. |
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| larny Guru Joined: 31/10/2011 Location: AustraliaPosts: 346 |
My understanding of what you have written is that you want several pumps to be switched on & off by the timer at once. So, in other words, either all of the pumps are running or they are all stopped. Is this correct? If so, then your question has nothing to do with the timer, it is an issue of choosing the correct relay. You could have one relay for each pump all operated from the timer. The relays would be chosen according to pump voltage & current. The timer would always be operating from the 12 Volt. So for example, if you want 4 pumps, you could use four 6 Volt relays in series from the 24 Volt supply all driven by the transistor Q1 as I have illustrated in the attachment. I won't comment on the 48 Volt option yet, I'm currently trying to clarify what you want. 
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| Lapsy Senior Member Joined: 28/01/2012 Location: AustraliaPosts: 103 |
It's all based on cost mate! Cheapest and most versatile are the 2 things I want. The relay we are currently going to attempt to use is built into the wall timer. We have established it is 24VDC in this model of arlec timer (Checkout the picture for a layout guide so far). For more info refer to Tinkers posts/replys as I am currently running with his idea. By all means discuss options and mods, I am keen to hear all ideas. I usually pick a bit of everyones ideas in the end, an try comming up with a good combo for the job. I've printed the article off and its decent mate! Yes it could be scanned a little better but I am cool with it mate! Don't waste time rescanning this though, it is good for a read and for free it's a delight. Ultra happy! You saved me $8 bucks man! I will chuck that into components... Like I said, have a good read of this sloppy thread of mine and yeah.... you will probably suss something out we all missed maybe or top off an already good method. I'm going to have to build a couple of these eventually or use a few different designs to test & work out what's good for me, so... keep throwing ideas out there! This is my signature ---> Scribble, scrawl, a bit of light pencil shading, some indelable ink and a bit of caligraphy. |
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| larny Guru Joined: 31/10/2011 Location: AustraliaPosts: 346 |
We all want to do things as economically as possible, but beware it's not a false economy. If you switch the pump motors using relay contacts that are not adequate to the task, or not properly protected from inductive spikes, then they will burn out - sooner or later and so it is likely to cost you more in the long run than it would if it was done properly from the outset. |
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| Lapsy Senior Member Joined: 28/01/2012 Location: AustraliaPosts: 103 |
Further Pictures for reference... 
Battery needs a charge by the looks of it. Was working a few days ago fully operational. Arlec Specky stuff from their site... Digital Time Switch Product Details 13 digitally programmed settings – 24 hours daily, weekday, weekend & 7 day programming options. Minimum time increment 1 minute. Set with digital accuracy and LCD display. 240 volt 10 amp rating, maximum load 2400 watt. Random setting, daylight saving and over-ride functions included. In-built battery maintains program when disconnected. Packaged: Clamshell Product code: PC787 (Different model to the silicon chip one) This is my signature ---> Scribble, scrawl, a bit of light pencil shading, some indelable ink and a bit of caligraphy. |
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| larny Guru Joined: 31/10/2011 Location: AustraliaPosts: 346 |
The spec indicates that the relay can switch 10 Amp. The photo of the relay indicates 16 Amp. The Silicon Chip article indicates 5 Amp: 10 Amp in brackets. So let's assume 10 Amp. The next question is: what is the starting current of your motors? You can decide this by measuring the resistance of the motor when it is not moving. Then measure the meter lead resistance by shorting the probes. Say the motor measues 1.6 Ohm, the leads measure 0.4 Ohm, then the motor resistance is 1.6 - 0.4 = 1.2 Ohm. So if the motor runs on 12 Volt, then (using Ohm's Law) the starting current will be 12/1.2 = 10 Amp. |
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| Lapsy Senior Member Joined: 28/01/2012 Location: AustraliaPosts: 103 |
Not selected a dc pump yet. Suggest some specs and I will have a look around. Thought I would hold off in case something changes as I get new ideas daily. Would like to see the timer running a dc current before investing further. Still considering a gravity valve solenoid also, but let's stick with pumps for the moment and see how it pans out. I think I get what your saying above, the pump or pumps, have to draw enough power to support the relay? Simplify the response a bit for me to completly understand as I don't work with electronics daily, I can just solder stuff, am patient, and have the ability to keep asking questions until it sinks in haha! I could probably find specs of the gravity solenoid in meantime for a look... Edited - The valve is 12vdc 500ma - all I know about it at the moment... This is my signature ---> Scribble, scrawl, a bit of light pencil shading, some indelable ink and a bit of caligraphy. |
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| Lapsy Senior Member Joined: 28/01/2012 Location: AustraliaPosts: 103 |
Another thing, this week jaycar have a special on a 12v 7.2ah SLA battery Jaycar $20Battery This is the battery I'm thinking of using or maybe a spare car battery. What you recon? This is my signature ---> Scribble, scrawl, a bit of light pencil shading, some indelable ink and a bit of caligraphy. |
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| Lapsy Senior Member Joined: 28/01/2012 Location: AustraliaPosts: 103 |
From your post you calculate the pump is 10Amp running on a 10Amp relay. So you are saying 1 pump for this relay has maxxed this out? If so then that's ok. 1 is better than none. Finding out the starting power without the actual pump infront of you could be a problem. I have a few AC pumps about the place but no Dc. Been meaning to draw & scan 2pictures of what I am aiming for (the master design!!) I know what you are saying. The circuit should be designed around the pump rather than the timer? This is my signature ---> Scribble, scrawl, a bit of light pencil shading, some indelable ink and a bit of caligraphy. |
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| larny Guru Joined: 31/10/2011 Location: AustraliaPosts: 346 |
The relay in the timer can switch at least 5 Amp. So it would be able to switch the valve solenoid. But you would need a diode across the coil to limit the back EMF when the relay is released. I'm at a loss to know what you are not understanding in my previous post. Timer operates relay, relay closes the pump circuit, pump runs. The relay contact rating must be sufficient to switch the starting current. A good relay would be the starter motor relay from a car since the starter motor has a very high starting current. So such a relay should be able to switch the pump without any problem. |
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| larny Guru Joined: 31/10/2011 Location: AustraliaPosts: 346 |
The battery you need will depend upon the pump current. For example, if the pump takes 1 Amp, then a 7.2 AH battery will last about 7.2 Hours before it needs recharging. But if the pump takes 2 Amp, then a 7.2 AH battery will last about 7.2/2 = 3.6 Hours. etc. |
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| larny Guru Joined: 31/10/2011 Location: AustraliaPosts: 346 |
I can't do much more until we have some pump specs to look at. So I suggest you have a look at pump suppliers web sites & possibly Ebay. |
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