POTD- PROJECT OF THE DAY: What Did You Make In Your Shop Today?

[Inferno]

This isn't a big deal but today I made a converted buck converter tester.

A WHAT??!!

Let me explain.

I have 100 buck converter modules that are capable of being adjustable (as purchased) or modified to deliver a more exact voltage.

What's a buck converter?

A buck converter is a DC to DC voltage converter. Specifically, for my purposes, stepping the voltage down.

The ones I purchased can accept 3-30v and will reduce as low as 3v, no matter how much you feed it.

I only need 3.3-5.1v but I needed something to accept EITHER 12v or 5v and...

This is turning into a long story.

I made a circuit board that is a "shield" for a device similar to an Arduino (but not arduino platform) with a specific purpose. The problem is that purpose can "need" either 12v or 5v pass through. HOWEVER, the microcontroller will fry at 5.5v. So it needs to be reduced to the controller only.

What am I thinking. I can't even explain this in purpose with props. What makes me think I can do it here?

Anyhow, below is the modified buck controller. It needs to have a trace severed and a bridge soldered to keep it AT 5v output. Since I'm doing 100 of them, I wanted to be able to check them quickly because my soldering and trace cutting skills aren't legendary.
You can see on the buck converter where I cut the trace and soldered a bridge.
And on the tester I can just plug the buck converter into the breadboard and it will tell me if I soldered and cut correctly.

It should be noted that these buck converters are TINY.

 

[ChazzC]

I understand. A good application – I've only used them to bump up the voltage from 5VDC to 9VDC.

 

[dkemppai]

It should be noted that these buck converters are TINY.

That can seem small to anyone who doesn't work with this stuff all day long. But for those who do, those are relatively large parts!

View attachment 471475

Watch your soldering iron temp, and add a little bit of flux to the dab of solder when you flow that solder joint. What you have there looks 'cold', and may be prone to failure at some point in the future. Without knowing the circuit design, a failure there could cause the voltage to either drop or go to the maximum. However, my guess is go to maximum (output = input).

Probably want to hold the iron on that joint just a bit longer, too. If you are using lead free solder (Although it doesn't look like it from the photo), getting the temp right may be difficult. For leaded solder running the iron at 630-650 should do it, lead free you may need just a bit more heat (650-670). But too high, and the flux burns up too quickly and you don't get a good solder joint. Feel free to PM me.

 

[Inferno]

That can seem small to anyone who doesn't work with this stuff all day long. But for those who do, those are relatively large parts!





Watch your soldering iron temp, and add a little bit of flux to the dab of solder when you flow that solder joint. What you have there looks 'cold', and may be prone to failure at some point in the future. Without knowing the circuit design, a failure there could cause the voltage to either drop or go to the maximum. However, my guess is go to maximum (output = input).

Probably want to hold the iron on that joint just a bit longer, too. If you are using lead free solder (Although it doesn't look like it from the photo), getting the temp right may be difficult. For leaded solder running the iron at 630-650 should do it, lead free you may need just a bit more heat (650-670). But too high, and the flux burns up too quickly and you don't get a good solder joint. Feel free to PM me.

I might take you up on the offer someday.

The solder I use is lead-free. It's not the best stuff but not the worst either. I've always had time bridging across pads. Unless I don't want to bridge across pads.
As for the solder point you see in the photo, though, The reason I am using that as the test piece is because the solder job was so bad. With my iron, with a new tip, I could solder 3-4 of them before needing to clean the tip.
If anything, the temp was too high. My iron was set to 825 (Which I know is incredibly high) which seemed to flow solder on a different project, better, with a 1.5mm tip. That project was just soldering headers.
I wasn't using flux, per se. I was using flux core solder. I know, I' a rookie

 

[pontiac428]

I wasn't using flux, per se. I was using flux core solder. I know, I' a rookie

By the time you make it through your "hundred bucks", you will be an expert at flowing solder on PCB bridge pads, I promise!

 

[rabler]

My iron was set to 825 (Which I know is incredibly high) which seemed to flow solder on a different project, better, with a 1.5mm tip. That project was just soldering headers.

The soldering irons don't measure the temperature right at the soldering tip. So a small tip soldering on something that sinks a lot of heat won't get the full temp while soldering, but it will get the high temp when the iron is not in contact with something. That just leads to losing the tinning on the soldering iron tip much faster. A larger tip will help significantly. I keep two soldering irons (plus a hot air rework station) so I can switch between a fine point and something more substantial easily. It's not always easy to tell what you'll need, some pads may connect to a large ground plane (pour) for example, and can need a surprising amount of heat.

If I'm trying to bridge jumper pads, I'll put solder on each pad individually (basically tinning them) first to get a nice bond, then do a quicker dab of solder and swipe between the pads.

 

[dkemppai]

I wasn't using flux, per se. I was using flux core solder. I know, I' a rookie

Not criticizing. Just offering suggestions...

Lead free tends to melt 217C to 225C vs. 183 for eutectic tin/lead. That means more heat needed.

If you lower the temp it should help a bunch. Hotter temp can be needed on large components or heavy copper boards, but much over 700F and most flux goes away fast.

1.5mm wedge tip or similar should be fine for that. If you're having trouble a bit bigger tip may help. Even if only for heat capacity.

Flux core with good flux content will probably do it.

Good luck!

 

[BGHansen]

I need to do some googling about the stop arm and fitting to the tapping heads as mine didn’t come with them. I’ll have to make them.

They're not anything elaborate, just a rod of steel to react against something solid. I don't know the thread size/pitch of your heads, probably inch. Try a few common bolts for a fit, then use some all-thread or run a die (or single point on your lathe).

Bruce

 

[Ben17484]

They're not anything elaborate, just a rod of steel to react against something solid. I don't know the thread size/pitch of your heads, probably inch. Try a few common bolts for a fit, then use some all-thread or run a die (or single point on your lathe).

Bruce


View attachment 471556

Thanks for the reply, but the SPD5/7 don’t have a threaded rod in to the head. They have three bolts on top of the head that a piece bolts on to and extends out. The pic below isn’t too clear, but hopefully you’ll see what I mean:

Sent from my iPhone using Tapatalk

 

[BGHansen]

Thanks for the reply, but the SPD5/7 don’t have a threaded rod in to the head. They have three bolts on top of the head that a piece bolts on to and extends out. The pic below isn’t too clear, but hopefully you’ll see what I mean:

Yup, just Google'd and got this picture. I'm assuming it's the "tennis racket" part.

Bruce