Electronic component assembly

A[L]C

A[L]C

A[L]C

Soldato
Joined
18 Oct 2002
Posts
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Maidenhead
Hi all,

Does anyone know of a small company or individual who will assemble a small electronics kit? I need a couple sound activated switches building. They come in a kit but I'm not competent enough at soldering. Only found large companies who obviously have a large minimum order.

Thanks
 
These sorts of kits are generally quite simple. A few through hole components mounted on a board. If this is the case give it a go yourself. Watch a few soldering videos and practise on something and you'll be fine.

Which kit is it?

If the kit is SMD components then things would be different.

I would offer to do it for you but don't have access to my soldering iron at the moment.
 
Not sure I can link to it (think its ok but don't want to take the chance), but if you google '445-054 switch' you can find it.

Thanks
 
That doesn't look too difficult.

A cheap £20 soldering iron will do the job. (I would get a decent, temperature controlled one if you plan to make this a regular thing). As above, just get some decent solder with flux and side cutters.

You may want some solder wick and/or solder sucker (for when you make a mistake).

Looking at the datasheet for the kit there is not a lot there to worry about. When soldering IC (chips) you sometimes have to be careful, but the kit uses an IC holder, which you solder to the board and not the IC directly - so no danger of harm there.

A good way to practice is to get some perfboard/prototypeboard/veroboard/ and a bag of components (stuff like resistors, capacitors etc are dirt cheap). Practice soldering them to the board. Once you're confident you will have no problem with the kit.

It can be fiddly at first and frustrating. Just watch some videos on Youtube and you'll be good to go. EEVBLOG has some great soldering tutorials. Here: Linky. Dave spends Part 1 talking about the myriad of tools. You can skim this if it's just a one-off project but I think it's worth watching.
 
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I've got some solid solder 0.3mm flux core 63% tin 37% lead, and one of the Maplin 50W solder stations, which I believe is pretty rubbish. Just don't really have the patience to do it!

edit: had someone I found offer to do it for £20 per kit plus postage
 
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Even a rubbish soldering iron will get the job done. They all get hot! If it's for a one-off then it will be sufficient.

Do you really want to pay close to £30 per kit just to avoid a bit of soldering? It would be cheaper for you to buy a load kits and practice on a few!
 
No not really! Looking at the image, the potentiometers (I think thats what they are) don't have any stalks on them. I'd like to put it inside a box with externally accessible stalks, so I guess I could change the potentiometers?

Looking at the images here:

https://www.google.co.uk/search?saf...JAL&ved=0CB4Qwg4oAA&biw=1600&bih=775#imgdii=_

it looks like a 22k and 100k? Is there any particular type I'd need?

edit: also, it looks like VR2 (the 100k pot) allows the relay to stay on between 1-60 seconds. If I wanted to extend this time, is that possible? The datasheet can be found here:

https://www.dropbox.com/sh/ye906mlqx2qfajy/AABy7St-0EYLCte5cpFn2cBra?dl=0
 
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Those are trimmer pots. They are generally used to make small adjustments and then left alone. Once set you shouldn't need to adjust them again.

Do you think you will be adjusting them a lot?
 
Potentially could be, yeah. One is to adjust the sound sensitivity, and one to adjust the delay that the light will stay on for. If you are talking you might want to decrease the sensitivity for example.
 
Any 3 pin potentiometer should work. I am assuming those trimmers are linear. You will need to be careful about pinout and the physical size of the replacement pots. A solution could be to have the pots on jumper wires (like the microphone) then it doesn't matter what size/pinout the part is. It may make it easier to position in a case/enclosure, too.
 
To give a bit of background, I am making what is known as a bivvy box (in carp fishing). Its basically a 12v battery in a box so you can charge your phone etc when fishing overnight(s).

Would this design work?

bivvy-box_zps6592f002.png


The way I think it will work is there is a main switch to turn the box off. When this is on, there is a 3 way switch which can either switch the LED strip on, off or to use the sound activated switch. The image for the sound activated switch is wrong, but in essence it has a 12v power supply, then can switch another power source (so it has 4 inputs), however I am running this off the same power source.

Independant to this are a voltmeter, usb charging socket and cigarette socket. Each of these are independently switched.

How's it looking?
 
Just the led.

The idea is when the switch detects the noise from the bite alarms it turns on allowing you to find your shoes/tent zip etc
 
Ah I see.

Given that it will be using your alarm to trigger the LED when in sound activated mode, then you probably don't need new pots to adjust the sensitivity. Adjust it so it reacts to a very loud sound. I doubt normal talking volume is louder than a fishing alarm... though I base that entirely on what my brother's fishing mate uses which he made himself. I suspect it used to be a car alarm! :p
 
Yeah that's true enough. I can put the receiver on top of the box too so should be fine.

Any ideas how I could increase the latching time from the advertised 60 seconds?
 
A[L]C;27446693 said:
Any ideas how I could increase the latching time from the advertised 60 seconds?
Click to expand...

Depends on the circuit but maybe replacing the 100k pot with a higher resistance such as 220k would double the time.

My guess is that in this configuration of a timer the op-amp senses the voltage in a capacitor which is fed through a resistor, once the voltage reaches a threshold (set by either the potentiometer or a resistor voltage divider) the op-amp would cause the circuit to reset, probably by flushing the stored energy out of another cap. So changing the pot would either increase the time it takes to reach the threshold or change the threshold point. You'd need the schematic or know the circuit to work it out for sure.

There's no micro here so it is all about the LM324 Quad op-amp in the middle.
 
I'd be more inclined to disassemble the bite alarm and hook its alarm output to a latching circuit to turn on the light. Much simpler than wording about noise sensors and triggering levels.
 
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