After a lot of head scratching and a fair amount of tweaking the code has finally been beaten into a working form. Because the hardware isn’t yet finished I have to capture the image by moving a camera with a long shutter speed across the board. The captured waveforms below show that the read/write cycle …
12: Globe PCB v2 soldered and ready for testing
After roughly two full days soldering I am finally finished and ready for testing. There will inevitably be some dry joints/bridges on the LEDs because they are really fiddly to solder. I still need to clean the flux residue off along with my grubby fingerprints but I shall do that as the last thing before …
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11: Globe PCB v2 arrives
The new boards are in, looking even nicer in matt than they did in gloss and ready for soldering. All those silly little mistakes from v1 have been taken care of so this should go smoothly.
10: Motor madness
After all the motor related issues of the first project I decided something pretty beefy was needed. If at ~480rpm my poor little DC motor was using about 180W, depending on the amount of power being lost as heat, it is fair to say that we will need about double that to be certain of reaching the …
9: Shiny new sliprings
These slip rings from MOFLON should mean that I never have to suffer the problems that the completely under-specced ones that I used back in the first display caused. Rated for 1500rpm with 4 power and 14 data lines these will allow the transfer of 5V up to 20A, HDMI and USB data and a tachometer pulse. Depending …
8: Safety first
The MKI used polycarbonate and aluminium for its case. Polycarbonate is well known for being bloody tough and easily worked, perfect for when you have no idea whether things are going to be flying off at you and you need to throw something together quickly and cheaply. The downside is that it tends to pick up and …
7: Globe PCB v1 – A somewhat mitigated disaster
Ok so this one was mostly my fault. Despite all the time I spent agonising over the schematic entry I ended up cocking a few things up. I was considering pasting and hot airing the board rather than manually soldering but since this would require doing each side of the board all in one go …
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6: Globe PCBs arrive
PCBs are in from China. I always buy two since most of the cost goes into tooling and it’s always good to have a backup in case you accidentally screw one up beyond repair. I used PCB Cart and I am pretty damn pleased with the service. I wont go into too much detail about the PCB …
5: Globe Test PCB
Before investing too much time and money in designing the full Globe PCB a smaller test board was needed. The purpose of this PCB was to test the following: TFP401 interface with FPGA SDRAM interface with FPGA Modifying EDIDs FPGA SPI controller & interface with TLC5951 First version of code The board was designed as a …
4: Globe PCB design
POV MKI used 4 PIC32s each controlling 4 TLC5951 LED drivers which each in turn drive 8 RGB LEDs, with one of the PICs acting as master and the other three as slaves. Since we are only increasing the number of LEDs, LED drivers and required SPI control lines, we can either apply more microcontrollers to …