Reverse Engineering Hall Affect Sensor For CNC

[Diver300]

Thanks for all your help i ordered 20 boards, any suggestions on soldering

Get some solder paste. Look on youtube for soldering videos.

If you've ordered from JLCPCB, you may get a solder paste stencil with the boards. If so, just use that to spread solder paste. To keep the stencil flat, it's best to support the whole of the stencil at the same height, so you need something around the board that is the same thickness as the board. I use some old or unused circuit boards around the board being pasted, but anything 1.6 mm thick will do. Use an old credit card as a squeegee.

If you don't have a stencil, make sure that the solder paste is in a syringe, which is how small quantities arrive anyhow. They often come with a suitable blunt needle for dispensing. Put a small blob of solder paste, really small, maybe 1/2 mm diameter on each pad.

Use tweezers to place the components into place. The solder paste will keep them in place if you handle them carefully.

Now you need to heat the board so that the solder melts. One method is a hot air gun. The type used for paint stripping is fine. You want about 300 °C, but if it's hotter than that, keep it high above the board and move it slowly closer. Keep the airflow low to stop blowing the components off.

An alternative is an old frying pan, and place the boards in that and then on a stove and slowly bring the temperature up.

With either heating method, make sure you have light and whatever magnification you need to be able to clearly see the components as they are heated. The solder paste will initially become more runny, and then dry out, and then melt. As it melts, it should flow onto the pads of the board and the connections of the components. The components will be pulled into place by the surface tension of the molten solder. Remove the heat source and leave until cold.

 

[kubeek]

How did you guys jump from 270 ohms to 2k7 etc?

 

[MaxHeadRoom78]

On the board pic, R2 looks like 2700 to me?
Max.

 

[kubeek]

Marking 2700 is normally 270 an 0 zeroes, so 270.

 

[madaxe]

never to late I'm still learning , i ordered my first board with no masks and they came back and told me to cancel the order so i learned to add solder and paste masks, and i made some design changes. which lead me to this, and its being made now.

 

[MaxHeadRoom78]

Marking 2700 is normally 270 an 0 zeroes, so 270.

I don't typically use SMT devices so overlooked that!
Max.

 

[Visitor]

never to late I'm still learning , i ordered my first board with no masks and they came back and told me to cancel the order so i learned to add solder and paste masks, and i made some design changes. which lead me to this, and its being made now.

View attachment 125572

I think you're going to have a terrible time soldering that board together without solder bridges. I'd move the components much further apart.

 

[Diver300]

never to late I'm still learning , i ordered my first board with no masks and they came back and told me to cancel the order so i learned to add solder and paste masks, and i made some design changes. which lead me to this, and its being made now.

View attachment 125572

I'm surprised that you've gone for such a different shape.

I would have expected the positions of the hole, the LED and the Hall sensor to have been constrained by the rest of the machine.

As far as the electronics goes, the shape makes no difference.

 

[madaxe]

for my first board and 20Euros, if its a disaster i can put it down to learning and try again. the Hall affect sensor i wanted as close to an end as possible so that I'm not limiting travel for an axis. I moved the hole to the center so one it screws into the 80/20 or Rexroth style extruded aluminium it would put even pressure on the board against the aluminium.

I purchased the mask with it so, i was going to try and use my rework hot air gun to attach the parts with solder paste T5. I guess i need to be sparing so i dont get bridging.

Thanks for all the feed back i will post on this thread as i go.

Cheers

Madaxe

 

[Visitor]

See my reply about using JLCPCB's assembly service if it doesn't work out (satisfied customer here) and post your board for review before you send it to be made.

The first time I tried their service, I paid less for the assembled boards than I would have paid for bare boards and a solder stencil (which I presume is what you mean by "mask").

 

[madaxe]

I just finished my first one, i learned a few things, i think i over heated the connectors and melted something i pushed a wire in and it does not stay in.

But i was able to see the green LED light up and when a magnet comes close it turns red

it maybe to sensitive, as it can detect the field from 60mm away, although i was using a neodymium magnet.

Any advice on the soldering i didn't order a mask so i used a very small screw driver and dabbed a very small amount of solder paste onto each connector, and then use the rework hot air gun to re-flow the solder

So thank you very much for all your help