Embedded Linux DSP System for Chemical and Radiation Threat Detection


iP Solu­tions brought exten­sive knowl­edge of Embed­ded Linux DSP sys­tems hard­ware and soft­ware to the Nevada Nan­otech Sys­tems (NNTS) project for explo­sive chem­i­cal and radi­a­tion threat detec­tion and  analy­sis. The project, CScout, was tar­geted for ship­ping con­tainer security.

Pre­vi­ous expe­ri­ence with com­plex embed­ded con­trol and data acqui­si­tion sys­tems enabled iP Solu­tions to imme­di­ately begin con­tribut­ing to this project.  The pri­mary goal was to design both hard­ware and soft­ware for using an NNTS Mol­e­c­u­lar Prop­er­ties Sen­sor (MPS) to col­lect, ana­lyze and present explo­sive chem­i­cal vapor threat data.  Addi­tion­ally, radi­a­tion spec­trum data was to be col­lected and ana­lyzed for any radi­a­tion threat com­po­nents.  This sys­tem was to be con­trolled and results com­mu­ni­cated remotely through a wire­less inter­face, the Mar­itime Asset Tag Track­ing Sys­tem (MATTS).  Also, a hard­wired net­work con­nec­tion was to enable more exten­sive main­te­nance and engi­neer­ing modes with web-based and ter­mi­nal based interfaces.

The CScout sys­tem was suc­cess­fully com­pleted with impres­sive mea­sure­ment results. This sys­tem will be used for demon­stra­tion of NNTS sen­sor capa­bil­i­ties to poten­tial customers.

MPS Sen­sor

The NNTS CScout project was designed around require­ments to stim­u­late and mea­sure the out­put of var­i­ous types of NNTS MPS sen­sor devices. The MPS devices typ­i­cally con­tain one or more tiny spe­cial­ized can­tilevers for per­form­ing calori­met­ric, tem­per­a­ture and mass mea­sure­ments. These can­tilevers are tiny div­ing board like fin­gers that pro­trude from bulk sil­i­con and are sur­rounded by air. These are con­sid­ered MEMS (micro elec­tro mechan­i­cal sys­tems) or NEMS (nano elec­tro mechan­i­cal sys­tems) depend­ing upon the dimen­sions involved.

 CScout Sys­tem

At the core of the CScout sys­tem is an embed­ded Linux Gen­eral Pur­pose Proces­sor (GPP) plat­form with a slave Dig­i­tal Sig­nal Proces­sor  (DSP).  This was imple­mented with a TI OMAPL137 which also includes other IP cores such as Ser­ial Periph­eral Inter­face (SPI) mas­ters (2) and Pulse-width Mod­u­la­tor PWM chan­nels (6).  These cores were used to drive addi­tional iP Solutions-designed cir­cuitry for imple­ment­ing the calori­met­ric, tem­per­a­ture and mass measurements.

Ser­vices Per­formed for NNTS

iP Solu­tions per­formed the fol­low­ing tasks for the Nevada Nan­otech Sys­tems CScout project:

  • Hard­ware and Soft­ware specifications
  • Eval­u­a­tion of lab­o­ra­tory proto-type testing
  • Design of new electronics
    • MPS piezo­elec­tric can­tilever stim­u­lus and response at 10 microsec­ond per stimulus-measurement cycle (1 channel)
    • MPS can­tilever resis­tor stim­u­lus and response at 15 microsec­ond per stimulus-measurement cycle (12 channels)
    • SPI dri­ver cir­cuits (Linux and DSP)
    • Power sys­tem
    • Radi­a­tion sen­sor interface
    • MATTS wire­less com­mu­ni­ca­tions interface
    • Pump con­troller (2)
    • Fan con­troller (2)
    • Heater con­trollers (4)
    • Peltier con­troller (1)
    • Inte­gra­tion of OMAPL137 proces­sor board
  • Design, build and test Printed Cir­cuit Boards (10)
  • Design and write software
    • Boot loader con­fig­u­ra­tion to mount USB root file system
    • Linux ker­nel enhancements
      • ker­nel SPI­dev enhance­ments to han­dle non-standard chip select scheme
      • USB drive implementation
    • Linux Dri­vers
      • SPI
      • PWM
      • General-purpose OMAP reg­is­ter access
      • Mod­i­fied / enhanced an exist­ing Gen­eral Pur­pose I/O (GPIO) driver
    • Linux dae­mons (services)
      • State machine cen­tral controller
      • Pro­por­tional Inte­gral Deriv­a­tive (PID) / PWM ser­vice pro­vides access to and con­trols the heaters (4) and pumps (2) of the CScout.  Also, the dae­mon mon­i­tors ambi­ent tem­per­a­ture and humidity.
      • MATTS ser­vice, which fea­tures the abil­ity to process requests from the Mar­itime Asset Track­ing Sys­tem.  The MATTS ser­vice con­tin­u­ally mon­i­tors and parses requests, and then based on spe­cific requests passes con­trol to user-designated and user-designed scripts for appro­pri­ate processing.
    • Linux util­i­ties: some util­i­ties are low-level “wrap­pers” for access­ing the dri­vers.  Other util­i­ties, built on the lower-level util­i­ties, pro­vide higher-level functionality.
    • DSP dri­vers
      • DSP SPI dri­ver (high speed)
      • Pre­cise tim­ing control
    • Pro­to­col dri­vers, which con­sist of a pair of exe­cuta­bles, one of which oper­ates in the OAMP L137 GPP and one that oper­ates in the DSP.  The GPP exe­cuta­bles pro­vide the inter­face to the pro­to­col dri­vers, while the DSP exe­cuta­bles directly inter­face to the CScout hard­ware to drive and acquire data from an MPS.
    • Radi­a­tion detec­tion and analysis
    • Web server and web appli­ca­tion imple­mented with Cherry Pi for main­te­nance and engi­neer­ing interface.
    • Self-test
  • Test pro­to­cols for test­ing dri­vers and con­trollers writ­ten in both Python, Bash and C code (many)
  • Pro­duc­tion pro­to­cols for MPS (many vari­a­tions) writ­ten in C code
    • Calori­met­ric (up to 12 channels)
      • Can­tilever resis­tor cur­rent sweep
      • Can­tilever resis­tor power sweep
      • Can­tilever resis­tor volt­age sweep
      • Can­tilever resis­tance measurement
      • Can­tilever volt­age measurement
      • Can­tilever resis­tor Power measurement
      • Peltier heating/cooling control
      • Pump con­trol
      • Fan con­trol
      • Heater con­trol
    • Piezo­elec­tric can­tilever (many variations)
      • Fre­quency sweep
      • Auto-null
      • Auto-peak detec­tion
      • Inte­grate with resis­tor measurements
      • Peltier heating/cooling control
      • Pump con­trol
      • Fan con­trol
      • Heater con­trol
    • Imple­ment GIT soft­ware revi­sion con­trol system
  • Build and test com­plete sys­tems and soft­ware protocols(10)
  • Train­ing
  • Doc­u­men­ta­tion
  • Final report


Comments are closed.