BeagleBone/GeigerCapePrototype

Introduction

Name	Role
Matt Ranostay	Backup HW design/Userspace applications/Presenter
Dimitris Sapountzakis	HW design
Pantelis Antoniou	Cape Manager + DT overlay support

Winner of Beagleboard.org Cape Contest

Design

The Geiger uses a simple circuit design (see references for schematic) and LND-712 tube but the magic is everything is an extension of Beaglebone + AM335x chip:

• PWM controls the boost converter
• Analog (AIN) feedback reports back current voltage of boost converter
• GPIO interrupts for radiations events

Future design work (some in progress):

• Fix current limiter with op-amps
• Use resistors that are within spec
• eCAP support to get rid of pulse extender part of PCB

Software

Geiger Cape kernel support is available in Beagleboard.org GitHub tree. There are demo applications available in the links below.

Communication with the cape is using Pantelis Antoniou's Capemanager + DT overlays driver interface (example output below):

Confirm Cape Manager picked up device
	# cd /sys/devices/ocp.2/bone-cape-geiger.11

	(start running)
	# echo 1 > run

	(power LED turns on and the event LED lights up on a “click”)

Display counts:
	# cat counter
	4344

Display VSENSE (voltage feedback loop) in Millivolts:
	# cat vsense
	538004

Hardware

Tubes Tested

NOTE: These values may change if inductor on future revs is different.

Name	Status	Duty Percent @ 20kHz
LND-712	Passed	60%
SBM-20	Passed	40%

Multimedia

ELCE 2012 Demo Picture

Video Links

Geiger Cape Sample App

CapeBus + Geiger Cape

ELC Europe 2012 Presentation

Matt Ranostay

Beaglebone: The Perfect Telemetry Platform?

PDF

Samples X11 + Python demo scripts + Schematic design:

Beaglebone Telemetry Presentation Resources