Here’s another piece of commercial gear, from an industrial air conditioning unit. These pumps are used to drain the condensate from the evaporator unit, so water doesn’t end up raining down from the ceiling. This is a peristaltic pump, with a silicone hose forming the pumping element. The test switch
Here’s some testing of the first bipolar supply for the Rigol scope. This is the +/-7.5v supply. Above is the supply built with it’s output filtering. The modules used are a PTN78020W for the positive rail & a PTN78060A for the negative rail. Under a 1A load across the total
A while ago I blogged about modifying the output voltage of some surplus Cisco switch power supplies to operate at 13.8v. Since I was able to score a nice Hammond 1598DSGYPBK ABS project box on eBay, I’ve built one of the supplies into a nice bench unit. Above is the
After watching a video over at Scullcom Hobby Electronics on YouTube, I figured I’d build one of these precision references to calibrate my multimeters. It’s based around a REF102P 10v precision reference & an INA105P precision unity gain differential amplifier. For full information, check out the video, I won’t go
As the first USB hub I was using was certainly not stable – it would not enumerate between boots & to get it working again would require waiting around 12 hours before applying power, it has been replaced. This is a cheapie eBay USB hub, of the type shown below.
The final part for the battery pack has finally arrived, the PCM boards. These modules protect the cells by cutting off the power at overcharge, undercharge & overcurrent. Each cell is connected individually on the right, 12v power appears on the left connections. These modules also ensure that all the
A few modifications were required to the SMPS modules to make the power rails stable enough to run the Pi & it’s monitor. Without these the rails were so noisy that instability was being caused. I have replaced the 100µF output capacitors & replaced them with 35v 4700µF caps. This
Progress is finally starting on the power supply unit for the Pi, fitted into the same case style as the Pi itself, this is an 8Ah Li-Poly battery pack with built in voltage regulation. Here are the regulators, fixed to the top of the enclosure. These provide the 12v &