Shared Projects by dewhisna

This QRE1113 Sensor Board can be used as a Line Sensor, quadrature encoder pickup, object detector, etc. It supports three different modes of operation, configurable, via component selection, as: Raw Sensor, Analog Output Sensor, or Digital Output Sensor.

When assembling, select the desired board mode type of raw, analog, or digital depending on your application. The first value listed for each component is the ‘raw’ mode value. The second is the ‘analog’ mode value. The third is the ‘digital’ mode value. “NC” means “No Component”. For example, for a digital mode board, use R1=150 Ohms, R2=220 Ohms, and R3=0 Ohms (jumper), and RC1=10nF (or 0.01uF) capacitor.

All surface mount resistors and capacitors are 1206 footprint for simple, easy hand assembly.

The Pinout in Digital and Analog modes is:

• 1) 5V+ Power In
• 2) Ground
• 3) Ground
• 4) Output

The Pinout in Raw Sensor mode is:

• 1) A (Anode)
• 2) K (Cathode)
• 3) E (Emitter)
• 4) C (Collector)

This board is similar to the two SparkFun Line Sensor Breakout boards https://www.sparkfun.com/products/9453 and https://www.sparkfun.com/products/9454, only more generic in that the same board can be configured either way or used as a raw sensor connection, such as for use with my Modulated Reflectivity Sensor Driver Shield.

The part selection, as detailed on the silkscreen, is identical to the SparkFun design except for the current limiting resistor for the sensor’s Infrared LED. I selected 150 Ohms and the SparkFun design uses 100 Ohms. The difference is approximately 25mA vs 38mA through the LED. The LED is rated at a max of 50mA. According to sensor datasheets, the peak wavelength output characteristics are achieved at 20mA. The higher current may help for slightly longer distance sensing, but will consume more power. You decide which one you wish to use.

For schematics, refer to the SparkFun schematics at the above links for the Digital and Analog modes. The Raw Mode is simply the four pins of the sensor routed to the connector.

The connector chosen is a 4-pin JST XHP series, 2.5mm connector. However, given the minimal difference between 2.5mm and a 0.100" or 2.54mm pitch connector, you should be able to also use a regular 0.100" pitch header connector if so desired.

NOTE: The 10K value shown for RC1 for ‘analog’ mode is low enough to keep the sensor’s phototransistor in the linear region. To push it into the switching region, use a 47K resistor instead to increase the gain nearly five times and make it function adequately for most applications. This is an example where Pololu got it right, but SparkFun didn’t, in my opinion. But, it depends on your application and whether you want the phototransistor in the linear region or switching region.

Laser Control Board Arduino Shield for the Laser Vision System. This board interfaces the laser PWM power modulation and on/off logic, as well as the LaserEye Reflection Sensors.

Version 2 with fixed voltage inverter circuit and corrections in power switching logic, changing it to switch the high-side instead of low-side. This version replaces the previous version.

Version 2 of AN3813K Brushless DC Motor Driver Arduino Shield (PLL Version) for use with VCR Cylinder Motors with precision speed control with feedback.

Specifically designed to be used with the Arduino ProMini PiDuino HAT and the STM32F746G Discovery Board, but can also be used on any Arduino Uno R3 compatible target. Supports both 5V and 3.3V logic with on-board level-shifters.

This version replaces the old Version 1 board. This version has improved voltage ranges and trim control for the V-to-F and F-to-V circuits, adds a flip-flop to make the V-to-F output 50% duty cycle, and fixes the AN3813K chip footprint without the need for an adapter board, as it’s a Shrunk DIP-18 not a Wide DIP-18.

Note: Populate either C1-C3 with R1-R3 or populate C12-C14 without R1-R3. C1-C3 is a low-side filter and C12-C14 is a high-side filter. Only one set is needed. Preference is generally for C12-C14. In either case, those capacitors should be bipolar.

All smaller surface mount discrete parts are 1206 footprint.

ERRATA: This version is missing a very important 10K pull-up resistor from LM331 V-to-F (U301) pin 3 (output) to pin 8 (+5VA). Without the pull-up resistor, the U305 flip-flop will not see the frequency output from the V-to-F and the U304 PLL will not have a frequency reference to lock to, keeping the Torque Error (ET) signal to the AN3813K in the off-condition, and the motor will not run.

Note: The 4046 PLL circuit often doesn’t drive the ET (Torque Error) signal low enough during initial startup to provide enough torque to get the motor spinning. Some clever programmatic manipulation of the Speed and ETR (ET Reference) DAC values after applying the motor enable signal can be made to work as an automatic startup solution.

However, the simplest solution, if manual start is acceptable, is to add a manual push-button between ET and GND to serve as a “start button” for the motor.

Another automatic solution would be to replace the push-button with a MOSFET transistor connected to an unused processor output pin, but that burns another processor pin.

See the AN3813K BLDC VCR Cylinder Motor Driver Arduino Shield PID Version V1 for the PID Version of this board. Both versions are viable solutions depending on preference of Analog PLL circuit or Digital PID via a microcontroller.

Simple Raspberry Pi HAT Board that provides the backfeed protection logic to power a Raspberry Pi board from an external +5V lab-grade power supply, as per the Raspberry Pi HAT Specs and the ZVD Circuit.

Charge-pump circuit to create a negative tracking split supply voltage that mirrors the single supply input voltage. This voltage inverter version uses the LM2662 and VIN must be between 1.5v and 5.5v.