Laser Assembly

Yesterday I got the Seeeduino by post. Here is a picture:

Seeeduino

As you can see at the upper part of the picture, the digital I/O sockets are soldered to the original position as they are in the arduino design. The problem with this is that the distance of the two connectors are not standard, so I cannot solder the pins on my stripboard properly. Fortunately Seeduino has places for the same connectors which are at standard distance. You can see the holes on the picture under the connectors. I tried to replace the left connector by desoldering it, but it did not come off easily, so I decided not to force it. I soldered it back and ordered an additional connector in my local shop. When that arrives I will solder that into the right place.

Yesterday I also started to assemble the laser.

Let me put a small disclaimer here. Playing with laser is dangerous. Never ever point the laser to eyes. Always test by pointing it on a wall or something non-reflecting surface from a proper distance. I do not take any responsibility for any damage caused by anyone following these instructions. Do it on your own risk.

Here is a picture:

laser

In my former post I wrote it works with a 1.5V battery, but I remembered wrong. It uses 3 LR44 button cells. Even better

disassembled laser

I removed the batteries. On the bottom of the holder there is a small spring for the positive contact. The body itself is the negative contact.

contacts

I drilled an approximately 3mm hole on the body, near to the spring:

hole

Then I soldered wires to the spring and the body:

wires soldered

This is the assembled stuff:

assembled laser

Then I connected this to a 5V power supply as it is. I measured about 40mA current when I switched it on. It is just about that much what the Arduino could provide, but it is quite on the edge. I connected a potentiometer in series and found that at 100 ohm it still works properly. I had 110 ohm resistance, so I connected that and measured 15mA current while the light was still strong enough. So that is it. I will use that.