So I have to buy a hot air gun in order to do this properly?

The "production" method is to use an oven. The home brew method converts a "toaster oven" and uses a profile controller. This http://www.zallus.com/msp430-reflow-oven-kit/ is probably the coolest that I have found.

Note, how the guy used standoffs to raise the PCB off the ground on the bench. If he mounts it, he might make the posts shorter and put them on the front.

The PCB manufacturer can supply stencils in either Kapton or stainless steel.

The board that I made, I did without hot air or solder paste. My first CPU chip that I soldered I didn't use hot air either, but 63/37 solder made all the difference in the world. I just tacked the corners and used an "upside down" technique which you solder the pins when the component was upside down. You just drag solder across all of the pins. 60/40 solder will easily bridge the pins.

Look at the AD8231 outline. http://www.analog.com/media/en/technical-documentation/data-sheets/AD8231.pdf#page=24 That part is 4 mm square or about 0.160". If you like fractions, then about 5/32 of an inch square. Pretty darn tiny. Note that the pads are mostly under the IC. There's no way to solder the "exposed pad" with an iron, but the pad does not need to be connected for this part. So, for proto-typing have proto-advantage do it. I think the other parts are 3 mm square.

1206 sized resistors that I chose are physically big, so you can handle them. Those parts (resistors typically) can be selected with a smaller package.

Page 32 here http://www.henkel-adhesives.com/com...ronics_Assy_Brochure_finalLR_Distribution.pdf discusses some adhesives that can assist assembly. it's not strictly required. But if you had a heavy part mounted on both sides of the board, then it's useful. It's an extra step for assemblers. Superglue works in a pinch.

I have the BK6000 (discontinued) version of this (BK8000 https://www.circuitspecialists.com/...8000-all-in-one-soldering-rework-station.html it's definitely a low-cost product. I had/have a few issues:

1. You can't use solder/de-solder at the same time.
2. The solder iron heater like to fall out. (fix: push it in once in a while)
3. The de-solder gun sticks in spring holder. Fixed with a $30.00 reamer. (borrowing is probably OK)
4. Not having the pin-out makes it hard to trouble-shoot (available elsewhere on-line)
5. You need a thermal compound on the gun system.

Metcal is often considered the cream of the crop because it uses an induction heater. Virtually no warm up or cool down time.
A self-contained de-solder tool is probably better, but they cost more than this.

At this stage, let proto-advantage do the IC soldering. The dipping this isn't going to work.

I have a story to tell. I did an automation project for a guy that built models from brass that was cut by etching. His assembly technique was to "drip" the solder. I told him about "resistance soldering" which passes a current through the parts and he switched to that method. It's really great for soldering pins on connectors.

 

In for a penny, in for a pound I guess! Looks like I'll have to accessorize the work bench just to prepare to assemble your circuit design. If these things are do delicate to put together I suppose you can't try it on the cheap. Bad connections are not going to make it any easier to test a design, so we need to make sure they are done right.

I guess I need to make an equipment list in addition to a components list! I'll try to read over the latest posts in more detail in the next day or two so that I can try to figure out where we stand regarding actually ordering some things to try out.

Dan

 

In for a penny, in for a pound I guess! Looks like I'll have to accessorize the work bench just to prepare to assemble your circuit design. If these things are do delicate to put together I suppose you can't try it on the cheap. Bad connections are not going to make it any easier to test a design, so we need to make sure they are done right.
Dan

There are so many different ways to breadboard, but in modern times it's just gotten much harder.

Let's just say, here's http://www.timefracture.org/radio.html a breadboard. The first was actually made from a board to cut bread on. That type of construction won't help you now.

The idea right now, is to build a circuit that looks like it will work and is build-able by hand with little outlay and not much more than that.
Any construction technique introduces parasitics or unwanted components, but in this case we don't have to worry about weird effects like the length of the lead poking through a PCB or that one resistor of 3K is not the equivalent of 3 resistors of 1K ohms in series or you have to mount a capacitor on it's edge, because it's a different value than if mounted on it's back. You have to ignore them when starting out. When your more "seasoned", you learn to neglect what's not important.

For now, "conventional current" (Something flows from positive to negative" doesn't care if the insulation is red, black, your finger or a bare wire.

Sometimes breadboards make t hard to "change a value" and sometimes you build them more than once. As you mentioned, loose connections doesn't make it any easier.

I guess I need to make an equipment list in addition to a components list! I'll try to read over the latest posts in more detail in the next day or two so that I can try to figure out where we stand regarding actually ordering some things to try out.

Hopefully not much of an equipment list except for non-magnetic tweezers.

 

There are so many different ways to breadboard, but in modern times it's just gotten much harder.

Let's just say, here's http://www.timefracture.org/radio.html a breadboard. The first was actually made from a board to cut bread on. That type of construction won't help you now.

The idea right now, is to build a circuit that looks like it will work and is build-able by hand with little outlay and not much more than that.
Any construction technique introduces parasitics or unwanted components, but in this case we don't have to worry about weird effects like the length of the lead poking through a PCB or that one resistor of 3K is not the equivalent of 3 resistors of 1K ohms in series or you have to mount a capacitor on it's edge, because it's a different value than if mounted on it's back. You have to ignore them when starting out. When your more "seasoned", you learn to neglect what's not important.

For now, "conventional current" (Something flows from positive to negative" doesn't care if the insulation is red, black, your finger or a bare wire.

Sometimes breadboards make t hard to "change a value" and sometimes you build them more than once. As you mentioned, loose connections doesn't make it any easier.



Hopefully not much of an equipment list except for non-magnetic tweezers.

 

Hopefully not much of an equipment list except for non-magnetic tweezers.

What about the heat gun for melting the solder?

 

What about the heat gun for melting the solder?

The heat guns I used were poorly controlled temperature wise and would probably blow the components off the board. Hot ailr soldering has low velocity, temperature controlled air with specific nozzles for the air pattern.

 

Yes, what I mean is that the heat gun needed for soldering tiny components looked like it might be an expensive part. If I have to have it, I'll get it but I wanted to be sure I wasn't buying things I didn't really need yet.

 

I agree. A temperature controlled iron is always nice. It almost became mandatory with the non-lead solder because of the high temperatures involved. Your breadboarding, so don't worry about it yet. Get proto-advantage to mount the parts to a DIP header. You don;t have to use surface mount resistors for breadboarding either.
http://www.electro-tech-online.com/threads/fair-or-not.150693/page-2#post-1294456A
The 0.1" grid has be "standardized" and so has 0.042 holes. So, make the parts fit the grid with the ability to change the values for now.
Get the parts made with the 0.025 square leads and the sockets designed for those. This is only one method. It's easy to deal with. It's easy to test for shorts. It's easy to replace components. I think it's more newbie friendly. But, it's slightly more expensive.

Whether on not your base board has holes is your choice.

You can use a solderless breadboard if you want too to test out the pieces, then transfer it to a more permanent type of breadboarding, but this type of breadboarding is more like you made a "one of" circuit and your happy with it, so you lose the plug-in pins.

This http://www.mouser.com/ProductDetail/Jonard-Industries/WD-30-B/ can end up being your friend. It's a very nice dispenser, cutter and stripper. WW wire is nearly impossible to strip.

You can get uninsulated solid wire in various gauges as well. http://www.mouser.com/ProductDetail/Belden-Wire-Cable/8023-000100

FYI: I don't think it will matter for you, but stranded wire comes in two strandings that I know of. One is more flexible than the other.
Screw terminals may or may not include "wire protectors". This is a flat piece of material that sandwiches between the setscrew and the wire so the screw doesn't separate the strands. Wire ferrules, e.g. http://www.mouser.com/ProductDetail/Phoenix-Contact/3201314 come in insulated and non insulated. They don't need to be crimped or soldered, but it puts a solid flexible tube around the wire.

You might eventually want to get a crimper for the smaller terminals. e.g. The sort of crimper that would be used to crimp a pin on PC serial ports. Not that you will use one, but the crimper is used for say a connector that goes to an off-board buzzer, battery. panel mount plug.
You can see that you would want to eliminate or minimize these.

First, you need a basic circuit that works.

For example: (9V battery)

There are some on the PCB options
There are off the PCB options, but mounted on the case.
There is a chassis option as well - replaceable from the outside without tools.

Your not there yet. Not even close.

 

if you want to assemble the product yourself initially, do the toaster oven mod.

 

I just found this http://www.jbctools.com/pdf/brochures/tarUSA.pdf company. They have a lot of stuff I haven't seen before and not cheap either.

So, yep the cheap pick and place is tweezers and the more expensive is a vacuum wand which can be manual or with a vacuum pump.
Re-work or repairing of stuff with large chips is a LOT harder. The IR Pre-heaters are used to apply heat to the other side for removal.

 

Daniel:

There is a glitch with the comparator circuit. It's wrong. It should sink current when the inputs are less than some value AND greater than some value. It's set up as .OR. so the alarm will sound the wrong way. It will sound when the probes are in the soup and not out of the soup.
It will likely be wired different at the outputs of the comparators and have additional parts. I forgot that "in the soup" produces voltages.

With just wiring changes and using one comparator and forcing the input to be unipolar it would work.

Look for a modification.

 

Daniel:

There is a glitch with the comparator circuit. It's wrong. It should sink current when the inputs are less than some value AND greater than some value. It's set up as .OR. so the alarm will sound the wrong way. It will sound when the probes are in the soup and not out of the soup.
It will likely be wired different at the outputs of the comparators and have additional parts. I forgot that "in the soup" produces voltages.

With just wiring changes and using one comparator and forcing the input to be unipolar it would work.

Look for a modification.

OK, thanks. In the meantime I can still get some materials together.

 

I slightly modified the alarm circuit on easyEDA and added a 1 M resistor. I need to create the 74LVC1G06-Q100 (Open Drain Inverter) part and include it. and include it possibly with a 0.1 uf ceramic bypass capacitor.