PBX blade for multiple extension home telephony

home-pbx-blade

It looks like a consumer good, but this PBX server blade was built by [Benoit Frigon] over the last couple of years. It brings multiple telephone extensions to his home service.

The device runs Asterisk open source PBX software. Because it will be on all the time he wanted something that doesn’t draw a lot of power. The 500 Mhz system seen on the left has just a half a gig of ram. It’s enough to do the job and at 10 Watts it’s not going to break the bank when it comes to paying the electric bills. The board in the middle is used to interface the analog handsets with the land line. From the look of it he’s got it rigged for two extensions.

That’s all somewhat par for the course with PBX rigs, but the enclosure is where he really shines. [Benoit] used 22 gauge aluminum sheet to fabricate the enclosure which is designed to blend in with the rest of his home’s rack mount hardware. To provide control at the rack he added his own LCD and touch-sensitive button interface to the front of the case based on a PIC 18F2520. The system can also be accessed via the web thanks to a custom interface he coded.

3D printer used to make custom blade server type mounting system

3d-printed-blade-server-mounts

We usually have no problem hacking together electronics into something useful. But finding an enclosure that makes sense for the build can be a real drag. In this case [Vincent Sanders] already had a working ARM build farm that leveraged the power of multiple ARM boards. But it was lying in a heap in the corner of the room and if it ever needed service or expansion it was going to be about as fun as having a cavity drilled. But no longer. He took inspiration from how a blade server rack works and 3D printed his own modular rail system for the hardware.

Each group of boards is now held securely in its own slot. The collection seen above mounts in a server rack which has its own power supply. This image is part way through the retrofit which explains why there’s a bunch of random pieces lying around yet. Instead of printing continuous rail [Vincent] uses a threaded rod to span the larger frame, securing small chunks of rail where needed by tightening nuts on either side of them. The white and red trays are prints he ordered from Shapeways designed to secure the eurocard form factor parts.

[Thanks Thomas]

ARM powered rack mount USB test equipment

developing-rack-mount-pcb-testing-tools

This is a device which [Limpkin] has been developing at his day job. It’s a high-speed testing interface for use with Physics experiments. We find it interesting because it uses an ARM microcontroller to implement CDC and MSD over USB.

The design is in two parts to make it work in a rack-mount situation. That big white connector allows cards to be swapped out. You can see the board on the right has a USB-A connector. When plugged in this enumerates as a control device (CDC) and a mass storage device (MSD) using fat32 as a file system.

The platform is being developed with open hardware and open source software in mind. If you’re working on a project that uses either of these USB functionalities this makes a swell reference. The ARM Cortex-M3 chip that he’s using is an AT91SAM3U but it should not be too hard to port the code for other similarly-capable ARM processors.

Repurposing server PSU for your charging needs

That grey box at the top of the photo is a modular power supply unit for a rack-mounted server system. [Sebastian] decided to repurpose it as a charging source for his RC batteries. He chose this HP DPS-600PB because of its power rating, efficiency, and you can get them at a reasonable price.

This is an active power factor corrected (APFC) PSU, which he says draws 40% less current than the non-APFC variety. Since he sometimes charges batteries in the field from a generator this is a big plus. But a bit of modification is necessary before it can be used as a source.

Since this is a rack device it has a set of connectors on the back. For power there are spade connectors which mate with a fin on the rack. He soldered positive and negative leads between the spades to interface with the battery chargers. The PSU won’t fire up if it’s not in the rack, so some jumper wires also need to be added connecting three of the interface pins.

With his modding all worked out he went on to use two PSUs for a 24V source, housing them to a nice carrying case while at it.

Follow

Get every new post delivered to your Inbox.

Join 92,441 other followers