The Infrared Diode and the Paste Dispenser
We were almost to throw in the towel trying to focus with the red diode when we did a quick test with the infrared one. We have a few pickups with the red diode burned but the infrared diodes seem still alive. When we discovered the way to turn on/off the blue and red pickup’s diodes we were also able to manage the infrared one (The infrared light is invisible to the human eye but you can see it through any video camera). But for some reason we didn’t see any wave in FE signal when trying to focus with it.
Reviewing old CD/DVD player’s manuals we saw that the photodiode is usually divided into two patterns: one for DVD and another for CD. That made us think that some pickup pin had to have the function of change from one photodiode pattern to the other. And so it was. There is a pin which allows switch from Blu-ray/DVD to CD mode. If not used, infrared diode turns on but no wave is obtained while focusing. We slightly modified the driver circuit and now we are able to focus with the infrared diode. The good news is that limiting the current with a resistor it seems it doesn't destroy itself. We still need to test a little more but it looks promising.
On the other hand, last week we designed and built the solder paste dispenser toolhead. The idea is that the robot also automates this task.
We used a small stepper motor, a linear axis, a small leadscrew and a syringe containing the solder paste. A few weeks ago we developed also the Eagle Cadsoft’s ULP program which generates the g-code file to move the robot and deposit the paste in the component's pads....
The first tests were positive but we still need to do more testing.
We have seen that in addition to solder paste the dispenser can also deposit any type of paste: clay, dough, chocolate, silicone, etc. and even print in 3D with those materials.