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Arduino-based front panel for QBUS backplanes

Mal

Experienced Member
Joined
Apr 3, 2008
Messages
91
Just thought I'd post a link here to a new Arduino-based project.

The Arduino monitors some front panel switches (Power On/Off, Run/Halt, LTC On/Off, Restart) and provides the necessary output signals for the 10-pin connector on the rear of a QBUS backplane (BDCOK H, BPOK H, BEVNT L, BHALT L).

As part of the power-up/power-down sequence for the PDP-11, it also turns an ATX power supply on and off, to power the backplane.

The LTC output defaults to 60Hz, but can also be configured for 50 Hz by adding a jumper.

The hardware is very simple: just an Arduino UNO. No Arduino "shield" or I/O electronics are required. You will of course need to wire up the front panel controls (4 switches and 2 LEDs) and fabricate the cabling to the ATX power supply and to the QBUS backplane.

Here's the link -> http://avitech.com.au/?page_id=1657

Feedback and bug reports are most welcome.

Malcolm.

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Thanks Al - I've added a link to your project on my project page.
 
Do note that cooling is not *optional* for QBus backplanes -- you can and most likely will cook your CPU board without a fan! A desk fan aimed at the side of the card cage, allowing air to pass over and under all of the inserted cards, would be sufficient.


Ouch! $30 USD for something John Wilson whipped up to start with!
 
@glitch - The main cost of Brad's setup seems to be the raw board priced at $20 - something like this is probably a $5 item from OSHPark. The rest of his BOM is only $7 and he's offered up the source and schematic, so not really a bad deal.

Jack
 
I thought I'd resurrect this thread to show off my own interpretation of Malcom's excellent Arduino-based QBUS front panel. Mine is based on a knock-off Arduino Nano that cost around $4, plus a smattering of other parts. It's minimal, but quite functional for my purposes.

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Note that the switch labels have yet to be added in these photos. The switches are (L to R): Power, Run/Halt, LTC Enable/Disable and Restart.

Mine runs a slightly modified version of Malcom's software that adapts it to the Nano. I've contributed this code back to him for future inclusion on his project page.

A big thank you to Malcom for developing this and making it available to the community. Anyone looking to build a skeletal QBUS system should definitely consider throwing one of these together.

--Jay
 
+1

Nice job on the write up.

Last year I did one using ttl and discreet components on a bread board, lol... It's still on a bread board.
 
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