It was a busy weekend at the lab building telemetry modules! We had some big wins, but it didn’t come without some hiccups and some late night running of the machines.

Flipping out

First, we received the solder paste stencil mounted backwards in it’s frame. Initially we were’t sure if we’d ruin it by flipping it over in the frame, damaging the mounting tangs, but the stencil manufacturer confirmed it should be possible to do without damage. At least once.

 

After prying the super thin stainless-steel stencil out of it’s plastic frame we re-mounted it and fitted it to the stencil frame. Good thing it worked out; waiting for a new stencil would’ve been supremely annoying.

LED upgrades

The next issue we ran into was getting the Pick and Place to see the fiducial marks on the circuit board. What are fiducial marks? They’re small targets on the circuit board the pick and place uses to excactly locate it using a downward facing camera – all in order to precisely place electronic components.

Our current boards sport a blue solder mask to have optimum contrast against the silver-colored fiducial marks when using the red downward facing camera.  (our red circuit boards were a bit of a disaster when used with a red illuminator, for hindsight-obvious reasons).  However, during board calibration, we were still having problems with the vision system identifying the marks: there was simply not enough contrast / brightness in the image!

We scrutinized the vision system more closely and determined that the illuminator ring of the machine was terribly dim. Evidently, the LEDs have degraded over time.  A snap decision and a 1+ hour detour resulted in a rebuilt illuminator using some bright red LEDs we normally use for shift light inventory. To do it we first we tested a string of 5 LEDs at a nominal 12v (the machine’s LED voltage supply) with a bias resistor. Once verified, Jeff expertly populated the ring with the updated LEDs. Much better!

 

 

We replaced the LED illuminator, played with the camera’s iris aperture, and finally fitted a paper diffuser in front of the LED and we were able to reliably detect the fiducial marks. We were finally ready to rock out some Telemetry boards.

 

A big stack of telemetry boards

It’s pretty amazing when things run smoothly: We rocked out a big stack of boards with very high build quality, and very little post assembly rework was needed. Here they are, all waiting for assembly and testing. These boards cannot wait to transmit some sweet race car data 🙂