6-9 V Interval Timer Commercial Availability

Thread Starter

mwh624

Joined Nov 6, 2009
28
Hi,
Does anyone know if there is an interval timer operating off of 6 or 9 volts that allows me to set an 'on' time of say approx 1-5 seconds and an off time of 1-20 or so seconds and then repeat for as long as the timer has power?

My google search has turned up http://www.apogeekits.com/555_timer_module.htm

which is exactly what I need except it runs on 12 volts, which I can't have.

Any body know of something currently available?
Thanks for reading
 

elec_mech

Joined Nov 12, 2008
1,500
Yes, this is a simple 555 IC built as an astable circuit. Looks like there are a handful of similar kits out by different manufacturers. Look at the link below for how it operates and what you may need to modify to fit your application. Like praondevou said, the relay is probably the only thing that requires the 12VDC to activate the coil (and maybe it'll work with less voltage and the manufacturer just picked 12VDC as it is easy to find 12VDC supplies).

Link:

http://www.doctronics.co.uk/555.htm#astable

These are real easy to build yourself, but if you need many or don't want to fuss with it, buying them premade is probably the way to go.
 

elec_mech

Joined Nov 12, 2008
1,500
Can I build one without having to solder?
Yes, you have two options depending on your needs.

#1. The quickest and simplest is to build the circuit on a breadboard. Ideally, breadboarding is only for temporary circuits for testing, but this is a fairly simple circuit, so if you make it on a breadboard and put it into a project box to keep dust off of it, you should be fine. There are some limitations with this method - this cannot be used for a critical application, in other words, odds of parts coming out or a contact losing grip over time can be high, so if it is important this not ever fail or it needs to robust or even needs to be moved regularly, you don't want to use this method.

#2. Before prototyping soldering breadboards were so widely available, people used to (and some still do) wire wrap. This requires a non-copper breadboard, a wire wrapping tool, and wire wrap. This method will hold up much better than method #1. The only caveat is the components need to have non-round leads. So, this is no problem for the 555 IC, but you may need additional connectors to hold your resistors and capacitors so you can attach the wire wrap. Wire wrap does not hold onto purely round leads. Now, someone with more experience may be able to enlighten you or correct me here on wire wrapping resistors and capacitors - you may be able to just bend them a little to get the wire to hold.

I can shoot links to materials for both if you'd like. This is real easy to solder onto a generic copper board if you decide to give soldering a try. I can shoot you links for materials for this route too.
 

Thread Starter

mwh624

Joined Nov 6, 2009
28
thanks elec mech
I'm going to see if I can modify the kit I found online first, same me some time.
If that don't work I will probably hit you up for some help.

Thanks
 

Thread Starter

mwh624

Joined Nov 6, 2009
28
Yes, you have two options depending on your needs.


I can shoot links to materials for both if you'd like. This is real easy to solder onto a generic copper board if you decide to give soldering a try. I can shoot you links for materials for this route too.
Could I get the materials list for a bread board setup?
Thanks

mwh624 "at" gmail dot com
 

elec_mech

Joined Nov 12, 2008
1,500
Hi mwh624,

I'm not sure where you're located, so I don't know which supplier to recommend. If in the U.S., you can go to a local RadioShack for some, although not all of the parts.

If you can order online, Electronics Express should have everything you need. I'm following the great link KMoffett sent as a parts guide.

Pots: 50K and 1M ohm

http://www.elexp.com/cmp_sts.htm

PCB:

http://www.elexp.com/pro_pb12.htm

100uF Capacitors:

http://www.elexp.com/cmp_601u.htm

1N4148 Diodes:

http://www.elexp.com/sem_n914.htm

1N4007 Diode:

http://www.elexp.com/sem_4001.htm

1K ohm resistors:

http://www.elexp.com/cmp_3005.htm

0.1uF Capacitor:

http://www.elexp.com/cmp_022p.htm

(Optional) LED:

http://www.elexp.com/opt_53rd.htm

NE555 IC:

http://www.elexp.com/ics_10cn.htm

Terminal Block if you choose - may be tricky with the PCB:

http://www.elexp.com/con_5tb1.htm


Hope this helps.
 

pdc

Joined Mar 1, 2009
10
I built the Velleman kit. It was dirt cheap at our local Fry's and worked well for what I wanted, which was to create an intermittent noise maker to keep birds out of my cherry trees. Unfortunately, before I could build a suitable enclosure, it rained and the cherries split open and were ruined. Next year project:) Anyway, should be modifiable.

Regards,
 

elec_mech

Joined Nov 12, 2008
1,500
do i need any type of voltage regulation for the 555?
You said you wanted to power this with 6-9V, DC correct?

How were you planning to provide that voltage? If you're using batteries, then no problem, the 555 can handle at least 12VDC if not more and can be powered with as little as 5VDC (possibly less, I'd have to look at the datasheet).

Let us know how you're supplying the power and we can advise what you'll need additionally, if anything.
 

KMoffett

Joined Dec 19, 2007
2,902
The key here is not the 555's voltage, but the relay coil voltage. You will have to change the relay to one that matches your supply voltage. Also consider, if battery operated, that the relay coil draws quite a bit of current. What will you be switching? If it's a dc load off of the same battery supply, you might get by with replacing the relay with a transistor, or even driving it directly off the 555.

Ken
 

Thread Starter

mwh624

Joined Nov 6, 2009
28
Thanks for all the good info.
I will be driving 6 volt DC motor.

I asked about the voltage for the 555 because I wasn't sure what it will handle. Also, I do plan on building a circuit myself and will use a 6 volt relay so it meshes well with the system.

As far as a transistor, how many amps could that handle?

I think the motor draws close to 1 Amp.

Thanks
 
Last edited:

elec_mech

Joined Nov 12, 2008
1,500
Everything looks good except:

1) You need to add a jumper between pins 2 (or 6) and the point where the two potentiometers come together. Look at the purple jumper I added in the attachment.

2) There needs to be a 1kΩ resistor between the LED and ground. You currently have the LED going straight to ground which might damage it.

After that, play with potentiometers until you see the LED blink.
 

Attachments

Thread Starter

mwh624

Joined Nov 6, 2009
28
Can anyone tell me what voltages I should see at the 8 pins of the 555 when the LED is on/off. I had the circuit wired up and working great on the bread boad, but tried to move it to a PC board and solder it together and now it does not work.

Thanks for reading
 
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