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Re: Suggestions for learning electronics/robotics?

Posted: Thu Mar 22, 2012 3:36 pm
by ridge
Back in the day when all components were through hole instead of surface mount, it was easier.

Today, surface mount components for all of their space saving goodness have almost killed hobby electronics because of the higher cost of a basic setup.

A good adjustable temperature solder station with a fine tipped soldering iron is a must.

A spool of thin rosin core solder. (Lead alloy if you can find it.)

A roll of solder wick.

A syringe of rosin flux to reflow solder joints that already have solder on them.

A pair of fine tipped stainless tweezers for handing fly poop size components...

A grounded wrist or ankle strap for static sensitive parts...

If you are past a certain age, a set of wearable magnifying lenses...

Removing components in one piece from any broken electronics stuff is good practice.

Wash your hands after working with the stuff, have adequate ventilation, eye protection is a good idea and store lead containing material away from children.

Re: Suggestions for learning electronics/robotics?

Posted: Thu Mar 22, 2012 3:45 pm
by zedin
ridge said:



A good adjustable temperature solder station with a fine tipped soldering iron is a must.


I had a question on that.. the old soldering iron I have is a fixed 40W weller.  Do you think for doing circuit board type stuff that is too high?  Should I get a adjustable?  And what are guidelines on what temp to use for what you are doing?  Been doing some searches at night but still kinda fumbling in the dark.

Re: Suggestions for learning electronics/robotics?

Posted: Thu Mar 22, 2012 3:49 pm
by Ravenous
For small electronics I have an 18W Antex iron.  Also a 25W one for larger jobs like soldering to potentiometers, etc.  Never needed more than these two.  Get a fine tip (2mm or so?) for the small iron and a proper stand and sponge.

Lead free solder is available these days, but for hand soldering apparently it's still best to stick to the olde-fashioned lead/tin stuff?

Re: Suggestions for learning electronics/robotics?

Posted: Thu Mar 22, 2012 4:02 pm
by ridge
Most data sheets have a graph for reflow temperatures. Ideally, you do not exceed those while hand working parts.

In the real world, keep the tip shiny clean for the best heat transfer and expose the components to the least amount of heating possible.

Inexpensive Chinese solder stations are fine *if* you can source replacement tips for them.

Re: Suggestions for learning electronics/robotics?

Posted: Thu Mar 22, 2012 4:14 pm
by MG2R
zedin said:


Now to find some projects to start with...


Check out http://www.letsmakerobots.com

zedin said:

the old soldering iron I have is a fixed 40W weller.  Do you think for doing circuit board type stuff that is too high?  Should I get a adjustable?  And what are guidelines on what temp to use for what you are doing?  Been doing some searches at night but still kinda fumbling in the dark.

I used to solder with an electrical soldering iron (100W+) and that went alright... You just have to be fast enough At the moment, I have a 15W soldering iron. Personally, I think it isn't powerful enough

I'd suggest you start with simply applying solder to an electrical wire, to get a feel of how the tin reacts. Then, start soldering electrical wires together to make shapes (your name, for example). That's how I learned it at school. Fool proof system

zedin said:

how would folks recommend I practice soldering?  Do they have just cheap blank circuit boards with holes and pads that I can practice with?

You can get one of these thingies, they come in a few varieties (one, two or three holes per 'island' or in straight lanes)... You can see 'em all here

Re: Suggestions for learning electronics/robotics?

Posted: Thu Mar 22, 2012 4:14 pm
by Ravenous
Years ago I had a job helping out in the college electronics labs - for first year students.  The first day was always how to solder and the exercise was as follows.  The small, elderly lab tech (who was a soldering god by the way) would give each student twelve short lengths of bare solid-core wire and tell them to make a cube out of it.

At the end of the day's soldering practice he would go around the lab with two pairs of pliers.  He would pull each cube to see if he could break it (no twisting, just a smooth straight pull with everything his little arms could muster, puling from the centre of two opposite wires).

The better ones survived.  I fear my own soldering might not be that good.  (Luckily the students didn't make me take the test.)

Re: Suggestions for learning electronics/robotics?

Posted: Thu Mar 22, 2012 4:19 pm
by MG2R
Ravenous said:


Years ago I had a job helping out in the college electronics labs - for first year students.  The first day was always how to solder and the exercise was as follows.  The small, elderly lab tech (who was a soldering god by the way) would give each student twelve short lengths of bare solid-core wire and tell them to make a cube out of it.

At the end of the day's soldering practice he would go around the lab with two pairs of pliers.  He would pull each cube to see if he could break it (no twisting, just a smooth straight pull with everything his little arms could muster, puling from the centre of two opposite wires).

The better ones survived.  I fear my own soldering might not be that good.  (Luckily the students didn't make me take the test.)



Same here, but we had to make a pyramid with our number (students numbered in alphabetical order) and class in two opposing sides...

Re: Suggestions for learning electronics/robotics?

Posted: Thu Mar 22, 2012 4:59 pm
by rurwin
Here's a challenge then.

The regular solids come in two varieties: those with triangular faces (Tetrahedron, Octahedron, Icosahedron), and those where three edges meet at every corner (Tetrahedron, Cube, Dodecahedron).

Which means that if you take one of the first type, build a pyramid on each face and then join the tops of the pyramids together, you will produce one of the second type. So you will have a cube containing an octahedron for example. It's a nice decoration to have around.

But you will have to construct many joints where six or more wires meet.

Re: Suggestions for learning electronics/robotics?

Posted: Thu Mar 22, 2012 5:46 pm
by Ravenous
Blimey I thought I was stretching things with my pi=2 assertion earlier today.

Based on the conductivity of copper & the wire specs, put a multimeter on two opposite corners of said cube-octahedron and calculate what the resistance will be.

That reminds me, zedin needs to add a mid-priced multimeter to his shopping list. Indispensable for all electronics (especially looking for shorts on veroboard).

Re: Suggestions for learning electronics/robotics?

Posted: Thu Mar 22, 2012 5:47 pm
by MG2R
Ravenous said:

That reminds me, zedin needs to add a mid-priced multimeter to his shopping list. Indispensable for all electronics (especially looking for shorts on veroboard).
Big-ass +1 on that!

Re: Suggestions for learning electronics/robotics?

Posted: Thu Mar 22, 2012 6:10 pm
by zedin
Define 'mid-range' =p

I have this one (or really similar) from a few years ago..

http://www.sears.com/shc/s/p_1.....ckType=G22

Re: Suggestions for learning electronics/robotics?

Posted: Thu Mar 22, 2012 6:14 pm
by MG2R
zedin said:


Define "mid-range" =p

I have this one (or really similar) from a few years ago..

http://www.sears.com/shc/s/p_1.....ckType=G22



You're all set

Re: Suggestions for learning electronics/robotics?

Posted: Thu Mar 22, 2012 7:43 pm
by SN
When I started work at 18 at ICL (remember them?) in 1983 as an A Level Trainee the first four weeks were spent in the Wiring School (yes we had a wiring school)

They taught us to solder and desolder chips on and off PCB's

We also got to play with an 8085 Microcontroller Kit (like seen on a thread on here elsewhere) complete with 6 digit LED display and hex keypad

These things have stood me in good stead ever since!

Re: Suggestions for learning electronics/robotics?

Posted: Thu Mar 22, 2012 10:10 pm
by exartemarte
zedin said:


I had a question on that.. the old soldering iron I have is a fixed 40W weller.  Do you think for doing circuit board type stuff that is too high?  Should I get a adjustable?  And what are guidelines on what temp to use for what you are doing?  Been doing some searches at night but still kinda fumbling in the dark.


A 40W Weller is fine. The Weller irons are temperature controlled: being 40W rather than, say, 25W, doesn't mean the iron is too hot, it just means that it heats up again more quickly after you've made a joint. Do use a fine tip though, as others have suggested. You can still get bits even for the older Wellers - get one to fit your iron (the model No should be on it somewhere). And do use a damp sponge, preferably on your soldering iron stand, to wipe the tip before use. And don't be tempted into SMD (surface mount devices) until you feel very confident with circuit boards and through-hole components. If then.

Re: Suggestions for learning electronics/robotics?

Posted: Thu Mar 22, 2012 10:25 pm
by exartemarte
SN said:


When I started work at 18 at ICL (remember them?) in 1983 as an A Level Trainee the first four weeks were spent in the Wiring School (yes we had a wiring school)


When I was moonlighting as a patrolman for Securicor in the early 70s one of the clients was ICL in Reading. We (patrolmen on several different beats) would meet up in the early hours at ICL because they had a free coffee machine. A few free drinks bought ICL a lot more security than they were actually paying for...