Export file:


  • RIS(for EndNote,Reference Manager,ProCite)
  • BibTex
  • Text


  • Citation Only
  • Citation and Abstract

A USB high resolution lock-in photometer

Health Innovation Centre, Teesside University, Borough Road, Middlesbrough, UK

Special Issues: Modern Electronic Instrumentation and Measurement Systems in Experimental Science and Engineering

A design is presented, in which the DDC112 current-input analogue-to-digital converter is combined with a PIC microcontroller and associated circuitry to give a simple and economical dual-beam photometer / electrometer. The PIC supervises the operation of the analogue-digital converter and performs a lock-in function using a rolling average filter, which enables intensity measurement to parts per million. It also synchronously controls a regulated current source to drive, typically, one or more power LEDs as light sources. It has been applied in various fluorescence and absorbance measurements and can be used with Cavity Enhanced Absorption Spectrometry to determine ultra-low absorbance. An expanded version has been created with a PIC32 processor handling eight channels for a PixelSensor multispectral detector. All circuit details and source code are made available.
  Article Metrics


1. Seetohul LN (2009) Novel applications of optical analytical techniques. Unpublished PhD Thesis, Teesside University.

2. Johnson M (2003) Photodetection and measurement: maximizing performance in optical systems. McGraw-Hill.

3. ibid, p165–166.

4. Jung WG (2006) High Impedance Sensors. Op Amp Applications Handbook. Section 4-4, Analog Devices, 4.39-4.56. Available from: https://www.analog.com/media/en/training-seminars/design-handbooks/Op-Amp-Applications/Section4.pdf.

5. Dorrington AA and Kunnemeyer R (2002) A simple microcontroller based digital lock-in amplifier for the detection of low level optical signals. Proceedings of the First IEEE International Workshop on Electronic Design, Test and Applications (DELTA 02), 486–488.    

6. ACF2101 Data Sheet: Texas Instruments. Available from: https://www.ti.com/lit/ds/symlink/acf2101.pdf.

7. Analog Devices Engineering (2009) Analog Switches and Multiplexers Basics. Available from: http://www.analog.com/media/en/training-seminars/tutorials/MT-088.pdf.

8. Baker BC (1993) Application Bulletin AB-57A Comparison of the noise performance between a FET transimpedance amplifier and a switched integrator. Available from: nic.ath.cx/PDF/Burr-Brown/apnotes/AB-057.pdf.

9. USB Implementers Forum (2000) USB 2.0 Specification section 5.7: 48. Available from: http://sdphca.ucsd.edu/Lab_Equip_Manuals/usb_20.pdf.

10. Burr-Brown Data Sheet (2004) SBAS085B Dual Current Input 20-Bit Analog-to-Digital Converter DDC112: 28. Available from: http://www.ti.com/lit/ds/symlink/ddc112.pdf.

11. Kester W and Bryant J (2009) MT-027 ADC Architectures VIII: Integrating ADCs. Available from: https://www.analog.com/media/en/training-seminars/tutorials/MT-027.pdf.

12. Amatek Scientific Instruments (2008) Technical Note TN 1001. Available from: https://www.ameteksi.com/-/media/ameteksi/download_links/documentations/7210/tn1001_specifying_lock-in_amplifiers.pdf.

13. Comment in usb_device.h (line 197) Microchip Libraries for Applications. Available from: http://ww1.microchip.com/downloads/en/softwarelibrary/mla_v2013_06_15_windows_installer.exe.

14. Zumbahlen H (2012) Staying Well Grounded. Available from: http://www.analog.com/en/analog-dialogue/articles/staying-well-grounded.html.

15. Microchip compiled library for inclusion in .net projects. Available from: http://ww1.microchip.com/downloads/en/softwarelibrary/mla_v2013_06_15_windows_installer.exe: HID class.dll found in \USB\Device - HID - Custom Demos\HID DLL - PC Software\Microsoft Visual C++ 2008 Express\ HID class.dll.

16. Linux library 'libusb' generic access to USB devices. Available from: https://libusb.info/.

17. Howlett M, et al. (2014) NPlot graph plotting library. Available from: http://netcontrols.org/nplot/wiki/index.php.

18. Measurement Computing HID library for Raspberry Pi. Available from: https://www.mccdaq.com/TechTips/TechTip-9.aspx.

19. Seetohul LN, Ali Z and Islam M (2009) Liquid-phase broadband cavity enhanced absorption spectroscopy (BBCEAS) studies in a 20 cm cell. Analyst 134: 1887–1895.    

20. Burr-Brown application Bulletin SBAA027. Available from: http://www.ti.com/lit/an/sbaa027/sbaa027.pdf

21. Johnson M (2003) Photodetection and measurement: maximizing performance in optical systems. McGraw-Hill, 104–108.

22. Bateson SW and Woodward AT (1994) High-resolution noise-rejecting ADC. Computing & Control Engineering Journal 6: 113–119.    

© 2019 the Author(s), licensee AIMS Press. This is an open access article distributed under the terms of the Creative Commons Attribution Licese (http://creativecommons.org/licenses/by/4.0)

Download full text in PDF

Export Citation

Article outline

Show full outline
Copyright © AIMS Press All Rights Reserved