Shared Projects

Pressure Sensor MPX5xxx I2C 16bit ADC ADS1100 - Arduino /Raspberry Drucksensor

*Note this version updates version 2017/001-015 with a fix for the I2C disconnect jumper.

This is a LEGO Minifigure sized development board using an Atmel SAMD21E 32-Bit ARM chip. I basically followed the recommended layout/setup from the SAMD21 spec sheets.

Included on Mini SAM is a WS2812B LED pad connected to PIN 27, a 0603 LED connected to PIN 15, a reset button with support components per the datasheet, and a generic button that is active HIGH on PIN 28. The 0603 LED is connected in series with a 1Kohm resistor, part of R1, and care should be taken when selecting an 0603 LED such that at a supply of 3.3V, no more than 5mA is required.

Programming port is a standard10-pin SWD for ARM based processors, which is a 2x5 1.27mm pitch connector. The SWD line is pulled up with a 1Kohm resistor, part of R1. In the BOM, either purchase the 2x5 straight pin connector OR the 2x5 POGO connector and do not populate board.

The SDA/SCL pins are pulled high with 4.7KOhm resistors, R2, per SDA/SCL recommendations.

The voltage regulator is an AP2112K-3.3V which is rated at 600mA at 3.3V. Plenty of current for the SAMD21E and a few other accessories such as the WS2812B.

This version has SMT layout for two single row 2.54mm pitch headers on the back. It is designed to be protoboard friendly and when populated the headers are the same width as a DIL package (7.62mm or .3") and span the center of a protoboard.

PINs 27 and 28 are not connected to headers - due to lack of space - but instead have two pads near the bottom of the board. PIN 27 is connected to the on-board WS2812B. PIN 28 is connected to the on-board BUTTON.

The Analog Reference (PIN AREF) - has a pair of decoupling/filtering capacitors.

The micro-USB connector has an RC filter between the case/shield of the connector and GND. If R6 and C13 are left un-populated the case/shield is an open circuit - which is the next best option. Also included is space for a PRTR5V0U2X ESD protection circuit on USB Data lines. This may also be left un-populated and USB will function normally.

I have put together a sample BOM via Mouser.com which I’m including here. It can be used as a reference. Optional, but highly recommended components: SW2812B 3535 LED, 0603 LED, SW2 (BUTTON), R4, R5, R6, C13, and PRTR5V0U2X. R1 is for the 0603 LED and SWCLK - If not populating the 0603 LED this may be left un-populated as well and programming via SWD should still work as I’ve seen other boards without the 1Kohm resistor on SWCLK. R2 is the 4.7Kohm pull-up resistor pair for SDA/SCL. Many breakout boards using chips that run off SDA/SCL typically come with the 4.7Kohm pull-up resistor pair included - as such it may not be needed on Mini SAM - but it is included for ease of future components. Please review the schematic for additional details and be aware that the BOM on Mouser.com may be out of date. The SW2812B is not in the Mouser BOM - due to lack of parts.

Mouser BOM

I would suggest not purchasing the 2.54mm pitch SMT male headers from Mouser, as you can find this much cheaper elsewhere. The best I could find on Mouser is (2) 5-Pin and (2) 6-Pin headers. Mini SAM requires (2) 11-PIN headers. I suggest buying breakaway headers in 25-50 PIN lengths.

Arduino FIRMWARE/BOOTLOADER is complete, but I’m still testing all functions. So far all PINs work in digital setup and all analog PINs work accordingly. ANALOG and special function pins (MOSI, SDA, SCK, etc) can be accessed in Arduino by their name.

Please check my Github for the latest design files and bootloade/firmware.

More details can be found on Github

Amiga Floppy Reader

3.5mm Jack Breadboard Adapter

For an ESP8266, with programming connectors and switches and supporting Deep Sleep mode. Designed to connect to a BME280 Temp/Humidity/Barometer by wire using I2C.

BOM

• C1 1uF 1206 SMD
• C2 10uF 1206 SMD
• P1 JST XH B04B 4 Pin Straight
• P2 2 Pin Header Straight
• P3 6 Pin Header Straight
• P4 JST XH B02B 2 Pin Straight
• R1 0R 1206 SMD 1%
• R2 4.7K 1206 SMD 1%
• R3 4.7K 1206 SMD 1%
• R6 4.7K 1206 SMD 1%
• SW1 ALPS SKQGAFE010 SMD Tactile NO
• SW2 ALPS SKQGAFE010 SMD Tactile NO
• U1 ESP-12F
• U2 MCP1700T-3302E/TT SOT-23

The board design has been updated since this version:

• I missed off a pull up resistor on CH_PD (but can easily be tacked on the back of the board if you use this version)
• redesigned the layout so my fingers could get at the switches ;-)
• Added a switch to bypass the regulator so the circuit could be used either with 3.2v LifePO4, or 3.7v Li-ion batteries

All updates on my github repo here: https://github.com/theopensourcerer/esp8266_envmonitor

(UNTESTED)

ESP8266-12 based temperature sensor. Using a waterproof DS18B20 1-wire sensor. Board powered from 12v DC using a switching regulator (Murata OKI 78SR)

• All resistors are 1206 SMD 4.7k
• All capacitors are 1206 10uF ceramic
• Main connectors are JST XH style.
• Tactile Switches are ALPS SKQGAFE010 SMD Tactile NO
• Switching Regulator is OKI-78SR-3.3/1.5-W36-C

Project details all on Github: https://github.com/theopensourcerer/esp8266-external-temp-sensor

servo controller for waveguide switch

This board provides a convenient conversion from the ESP8266 boards which have 2mm pitch pin holes to a 2.54mm standard breadboard pitch size. The pinlet board is from the ESPARDUCAM Project by kanflo. Pogo pins can be used as shown in the website to program multiple boards without soldering.

Original link to the GIT

INA260 Breakout Board Condensed

A Simple 555 Based PWM Controller kit. Completely though hole.

Fits 7x7mm Switches and a 3mm LED. Use a 100 to 330 ohm resistor for the LED. Higher values are for dimmer light.

MCP3202 + KMZ60 - hall magnetoresistive sensor board 12bit precision with digital output

A shield for D1 Mini for controlling 16 servos.

Buy it on Tindie: https://www.tindie.com/products/deshipu/16-channel-servo-shield-for-d1-mini/

RFID_PI HAT v1.5b

Voltage regulator board. This board can supply 3.3V and 5V simultaneously to a circuit mounted on a breadboard. The rails are fully configurable.

XHRA-2HPA-TQ64 minimal system board

INA260 Breakout Board

Mechaduino01

2 layer board of 1.65x1.65 inches (41.94x41.94mm). $13.60 for three.

Mechaduino Kickstarter

Logo image

Engineers use servo motors to achieve the precision motion required in applications such as robotics, automation, and CNC manufacturing. Like RC servos, industrial servos actively correct for external disturbances. Unlike RC servos, industrial servos can provide very accurate motion, and often support advanced motion control modes. Unfortunately the cost of industrial servos is prohibitive to the individual maker (thousands of dollars per motor).

We’ve been developing an affordable open-source industrial servo motor, opening the door to sophisticated mechatronics applications. Our design leverages the low cost of mass produced stepper motors. We are able to achieve very high resolution via 14b encoder feedback (after calibration routine!).

Project Goals

Position, velocity, torque loops
Step & direction inputs for drop-in compatibility with stepper motors / step stick
I2c, serial inputs
Customizable/open source with access to internal variables
Transparent and user-definable control algorithms (commercial servos often lack this)
Arduino compatible with easy to use interface
High resolution pointing (sub 0.1 degree)
Low cost (should not be a huge leap from stepper + stepstick cost)
Serial interfaces for inter-motor communication
On-board processor allows for stand alone for simple applications
Adjustable commutation profiles
PID auto tuning
Anti-cogging capable
Open to customization. Outside of our firmware, we see Mechaduino as a very useful hardware package. If you would like to use the stepper motor in open loop mode w/ encoder to verify location, you can do that.

Strategy

An industrial servo motor can be broken down into four main components (below). First we looked at each of these components and tried to piece together an affordable breadboard-level prototype. After some experimentation, we were able to distill out a working lineup of components. From there, we’ve been iterating on our design, working out all the kinks, and tuning the control loops. It’s starting to come together!

…Back to those four main components:

The actual motor, usually of the brushless dc variety. When you look at industrial servo motors, a big chunk of the cost is the motor itself. They are often custom built, or at least built in limited quantities, which means $$$. Watt for watt, I'd guess that a mass produced NEMA 17 or NEMA 23 stepper motor is between a tenth and a hundredth the cost of the BDC motors used in industrial servos. Although their design is optimized for "stepping," stepper motors are really just 50-pole brushless dc motors. They can be controlled exactly like a more traditional 3 phase BDC motor with more poles. So that's the plan. It's working!

A sensor for feedback, usually an encoder. Optical encoders are pretty standard, but get quite pricey if you want high resolution and/or absolute position information. We were intrigued by some of the cheap, high resolution magnetic encoders offered by vendors like AMS. It turns out that although they claim 12 and 14 bit resolutions (that's 0.09 and 0.02 degrees respectively), they suffer from non-linearities on the order of a degree or so! However, we found that this non-linearity is very repeatable, and we were able to develop a quick, self contained (on motor) calibration routine that restores resolution to better than 0.1 degrees. (More on this later. This was a significant design effort and is worthy of its own build log!)

Drive circuitry/power electronics to excite the motor windings. Many industrial servos use discrete H bridges. Each phase requires it's own H bridge ( for a two phase motor... half bridges for each in a three phase motor), which consists of at least 4 if not 8 (...including freewheeling diodes) discrete switching devices. Throw in gate drive circuitry, and things start to get expensive. We hoped to find a single-chip, integrated solution that would allow for current feedback, and we found just that in the A4954 dual full bridge PWM driver.

Control Electronics. Usually a microcontroller or FPGA. Early on, we decided that Arduino compatibility was a must in order to make the firmware as accessible as possible. We chose to use a SAMD21 ARM M0+ (Arduino Zero compatible) processor to balance cost and performance. Our breadboard prototype system verified that this processor was more than capable of executing the necessary algorithms.

Application Examples:

Fine, closed loop positioning for 3D printers
Fine pointing for optics (laser, telescope, camera gimbal)
Velocity loop for a record player
Force feedback/impedance control for robotics
Force feedback for gaming controllers
Adjustable mechanical impedance: virtual spring,mass,damper
Electrical gearing between two axes on a cnc machine, etc.
Haptics
Tele-operation
Gravity-cancellation (counter the gravitational torques on a robotic arm for example)
Load detection and characterization (simple case: use as a scale!)
Paper towel/tp dispenser
Variable load (brake)
Variable load (generator)
After market valve control (automate a garden hose, etc)

Other Advantages:

Finer resolution than stepper motors (0.02 degrees)
True closed loop for disturbance rejection
Lower power consumption: only uses power to fight disturbances. This in turn means higher peak torque.
Absolute position control (not incremental). No need to home on power-on.

License

All Mechaduino related materials are released under the Creative Commons Attribution Share-Alike 4.0 License

I had some difficulty getting some of the aesthetics on the board, namely the silk of tropical labs and the Mechaduino in copper on the top layer…everything else is 100% as is from his github

Breakout for Two Pololu Low-Voltage Stepper Motor Drivers