Tag: synchronous

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Raspberry Pi 3 Model B+ Initial Tests & Benchmarks

Raspberry Pi 3 Model B+
Raspberry Pi 3 Model B+

Yesterday, the Raspberry Pi community got a nice surprise – a new Pi! This one has some improved features over the previous RPi 3 Model B:

  • Improved CPU – 64-Bit 1.4GHz Quad-Core BCM2837B0
  • Improved WiFi – Dual Band 802.11b/g/n/ac. This is now under a shield on the top of the board.
  • Improved Ethernet – The USB/Ethernet IC has been replaced with a LAN7515, supporting gigabit ethernet. The backhaul is still over USB2 though, so this would max out at about 300Mbit/s
  • PoE Support – There’s a new 4-pin header, and a matching HAT for power over ethernet support.
Chipset
Chipset

The USB/LAN Controller is now a BGA package, supporting gigabit ethernet. The USB connections are still USB2 though, limiting total bandwidth. This shouldn’t be much of an issue though, since anything over the 100Mbit connection we’ve had previously is an improvement.

CPU & Radio
CPU & Radio

The CPU now has a metal heatspreader on top of the die, no doubt to help with cooling under heavy loads. As far as I know, it’s still the same silicon under the hood though. The WiFi radio is under the shielding can to the top left, with the PCB trace antenna down the left edge of the board.

Power Controller
Power Controller

The power supplies are handled on this new Pi by the MaxLinear MxL7704, from what I can tell from MaxLinear’s page, it seems to be somewhat of a collaborative effort to find something that would do the best job, since they apparently worked with the Foundation to get this one right. This IC apparently includes four synchronous step-down buck regulators that provide system, memory, I/O and core power from 1.5A to 4A. An on-board 100mA LDO provides clean 1.5V to 3.6V power for analog sub-systems. This PMIC utilizes a conditional sequencing state machine that is flexible enough to meet the requirements of virtually any processor.

PCB Bottom
PCB Bottom

The bottom of the PCB has the Elpida 1GB RAM package, which is LPDDR2, along with the MicroSD slot.

A quick benchmark running Raspbian Lite & a SanDisk Ultra 32GB Class 10 SD card gives some nice results:

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Fluval 203 Canister Filter

Assembly
Assembly

Here is an old fish tank external filter & a few pics of the insides.

Label
Label

Label on the front of the pump head. Fittings on either side of the motor are water I/O.

Pump
Pump

Underside of the pump head, inlet is on the right, outlet from the pump is on the left. Pump intake in centre.

Pump Parts
Pump Parts

Pump disassembled. This pump requires no shaft seals as the impeller is driven magnetically with a synchronous motor.

Filter Stack
Filter Stack

Filter stack removed from the unit. From left: foam media, activated charcoal/gravel & ceramic pellets.

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Motorised Valve

This is the internals of a motorised valve for central heating systems. Here the top is removed showing the motor & microswitch.

Left side of the valve, showing the gearing under the motor, & the valve body under the powerhead.

Right side of the valve, showing the sprung mechanism of the valve quadrant.

Here the motor has been removed from the powerhead, showing the microswitch & the sprung quadrant gear. This spring keeps the valve closed until the motor is energized. The motor remains energized to hold the valve open.

Here the valve body has been opened showing the internal components. The rubber valve rotates on the shaft, blocking the lower port of the valve when in operation.

The motor’s protective cap has been removed here showing the rotor. This is a synchronous motor, of a special type for use in motorised valves. As the windings need to be continuously energized to hold the valve open, it is designed not to burn out under this load. 240v AC 50Hz, 5RPM.

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