Sunflower Array

I’ve made the PCB for with the 74AC240 based on this design from http://www.smfr.org/robots/robot_images/dualsolarhead_schematic.png : Hoping that it works better than the 540 version with the solar midpoint. IT DOES! It is far more responsive and efficient and works with the solar panel! It has a funny quirk where it will first turn the wrong… Continue reading Sunflower Array

Dual Solar Tracking Part III

Another idea is to start with the actual solution (two small servos) and make it look better. It’s sturdy and already balanced. It just needs a hinge and a tilting arm: With a makeshift hinge and tilt arm: This would only require an Arduino mini pro and some super caps charged by a solar panel… Continue reading Dual Solar Tracking Part III

Dual Solar Tracking Part II

Continuing the project of making a small solar tracking device. **** Idea to simplify the circuit drastically and make the 3D model a bit more robust and less fragile so it is far easier to assemble and won’t topple over (while hopefully maintaining some elegance…)  -Battery-powered (and possibly solar recharging through very simple circuit):  … Continue reading Dual Solar Tracking Part II

Robot Arm

Here is the final product:     After the relative success of the foam cutting machine, I would like to build a medium-sized robot arm which can actually be a useful tool in the lab and not just a toy. The main questions appear to be: how to increase the torque of the stepper motors?… Continue reading Robot Arm

Medium-sized CNC Foam Cutter (with Léon Reboul)

Here is the finished product:   And here is a quick video cutting foam:   Another video showing the stage testing:     Here are the files on Thingiverse: https://www.thingiverse.com/thing:4428184 We’ll be harvesting parts from an old Ultimaker 2. The stuff we plan to use: Based on what we found, we plan on making two… Continue reading Medium-sized CNC Foam Cutter (with Léon Reboul)

DIY Centrifuge

Based on Hackteria’s DIY Centrifuge (https://hackteria.org/wiki/Hacked_Hard-disc_Centrifuge) Controlling a Three-Phase DC Brushless motor (BLDC) of a Hard Drive primer: https://www.monolithicpower.com/pub/media/document/Brushless_DC_Motor_Fundamentals.pdf Similar to a stepper motor (except a BLDC is meant to run smoothly not in steps) but with three stators (if it’s an inrunner, an outrunner has the permanent magnets around the shaft):    At the… Continue reading DIY Centrifuge

EWOD (electro wetting on dialectric)

This project is based on Gaudi Lab’s OpenDrop (https://www.gaudi.ch/OpenDrop/) Here is the github for Fablab Digiscope’s iteration of the project: https://github.com/merlinmarrs/OpenDrop We don’t have high voltage MOSFETs so we are using relays instead. In parallel we will be sourcing the components to make the high voltage power supply using a boost converter that takes 12V… Continue reading EWOD (electro wetting on dialectric)

Fever monitor

This device is intended to be installed within the 3D printed forehead mount of a visor.  It’s being developed at this github: https://github.com/merlinmarrs/Fever-Meter The top board is a boost regulator taking the 2V from a pair of miniature backup batteries, and the bottom side is an attiny85 with I2C temperature sensor and indication led.  This project… Continue reading Fever monitor

IR thermometer with POV display

This contactless temperature sensor has a POV display for the temperature readout.  Here is the github: https://github.com/merlinmarrs/POV-fever-meter Here is what it looks like in a dark room with long exposure: The plan was to have the device spell out the message in reverse after displaying it normally to allow a certain frequency of waving the… Continue reading IR thermometer with POV display

Dispositif Désinfection

Developed by Fablab Digiscope. A board to sense the temperature and illumination, and act as an interface, inside a disinfection device: https://github.com/merlinmarrs/anti-viral-dispositif/ A main board and secondary board to control a disinfection chamber based on this tutorial: http://www.needlab.org/face-masks-disinfection-device Here is the BOM: Standard components: 7 segment display x2 595 Shift Register x2 LED x 2 Photocell… Continue reading Dispositif Désinfection

Syringe pump mechanism + electronics

  This is the stepper motor driver design we are hoping to use to control a syringe. Here is the PDF describing the assembly: etapes fab venti v2 And here is the github repo: https://github.com/merlinmarrs/FabVenti   This is the syringe pumping prototype I developed. It uses 8020, a NEMA stepper with built in threaded rod,… Continue reading Syringe pump mechanism + electronics

Solar Electronics Primer

The goal of this primer is to introduce people to mini DIY solar energy applications. New solar product I just found out about:                    

Fab 15 Part VII

Here are some videos of the current prototypes:         I want to focus this project on the design of the 2 axis rotation mechanism. The electronics and code side has already been explored and I can’t offer anything new here as a designer. (I’ll abstract the sensing and radio side of thing… Continue reading Fab 15 Part VII

Circuit Protection + PCB Design Rules of Thumb

I just destroyed a circuit I spent over a week preparing and I decided I would learn how to better protect my circuits. Reverse Polarity protection: A diode can be used to protect a circuit but it will drop 0.7V and will waste power. A shotky diode will only drop .3-.4V but it has the… Continue reading Circuit Protection + PCB Design Rules of Thumb

Fab 15 Part VI

Here is my first attempt at making a video of this all working: I would like the next version of the video to show:-starting charging from zero.-the burst of packets sent at the begining and how it finds a balance afterwards.   -the sky in the background so it’s easy to understand how the clouds effect… Continue reading Fab 15 Part VI

DIY Mini Drone

For a change, this is a video of me working on the boards for this project:     Radios are working, I’m struggling with the best way to poll the joysticks. I think I need to use Pin Change Interrupts (Interrupts for pins other than those dedicated for interrupting). The other option is just to… Continue reading DIY Mini Drone

Binary Visualizing

Using the tool bin vis, which simply assigns a shade of grey for each byte in a file, it’s possible to represent the structure of pieces of a file. Check it out, these are found 3D files from various software programs:   Found a cool surprise when I uploaded a .BMP file, the bytes map… Continue reading Binary Visualizing

UPSI Lecture Prep

  To “present my projects or any other insights on digital fabrication, education and architecture.” The context; “The class is the second part of an intensive course on 3d modelling and CNC milling to make an 1:1 architectural structure based on simple modules.” Here are some questions I could respond to: What are the seams,… Continue reading UPSI Lecture Prep

Contactless Current Meter (IN PROGRESS)

In line with a series of low-power and energy harvesting devices I would like to make a simple Current Meter which can display the amount of energy being consumed by a given machine in our lab. I imagine the unit as a standalone thing which would use the power it harvests to power itself if… Continue reading Contactless Current Meter (IN PROGRESS)

hand-powered flashlight (IN PROGRESS)

As part of a series of low-power and power harvesting devices (such as https://steemit.com/technology/@proteus-h/my-diy-passive-mini-radio-microwave-detector), I would like to make a hand-crankable or shakeable torch. I like these projects because they are not too complex, and they demonstrate very tangibly the energy that can be harvested in the environment. from https://www.kjmagnetics.com/blog.asp?p=shake-flashlight:   A Servo makes a… Continue reading hand-powered flashlight (IN PROGRESS)

Design Primer – Presentation for Digital Fabrication class at UP-Sud December 2019

  This presentation serves to introduce non-designers to the culture of design. It proposes that design is like a trip, one that should take the designer outside of the “diameter of the obvious” (everything that can be imagined on day 1 and constitutes low-hanging fruit or cliche), to an unexpected place. Every design journey is… Continue reading Design Primer – Presentation for Digital Fabrication class at UP-Sud December 2019

Synthesizer

  Karl and I are planning to work on other sides of the ocean on this project together. Karl will continue working on the overall collection and interaction of the modules, I’ll work on prototyping one module at a time. We hope to find a collection of modules that are cool and to see which… Continue reading Synthesizer

Solar-Powered Autonomous Wildlife Photography

This project uses the LTC3105 Solar Harvesting IC from Linear Technologies, an Atmega328P along with a Serial TTL camera and an SD mini card for saving the images. The plan is to create a waterproof casing for this device and then install it in a nearby forest and set it to take photographs when it… Continue reading Solar-Powered Autonomous Wildlife Photography

Drawing Machine

We wanted to make an interactive Draw Bot which would make nice drawings near the entrance of the Fab Lab and invite guests to upload their own drawings too. I am working with our PhD candidate Nawel Khenak on this project. We downloaded most of the 3D parts from this kit on Thingiverse: https://www.thingiverse.com/thing:798076 But we… Continue reading Drawing Machine

Fablab RGB LED Sign

  This project has the goal of making the Fab Lab Digiscope location visible from the exterior of the building and meanwhile creating an a display that users can code themselves.   After testing with painting tape, it was clear that giant letters made from material would not be sufficient to make the Fablab visible… Continue reading Fablab RGB LED Sign

Raster Image Compression/Interlacing/Encoding Index Representation (IN PROGRESS)

How can non experts quickly get an idea of  the way in which our computers see our raster images? I have previously focused my energy on how vectors are internally represented because I had the impression that pixel-based rasters were always stored in a predictable top to bottom, left to right arrays in computer memory.… Continue reading Raster Image Compression/Interlacing/Encoding Index Representation (IN PROGRESS)

Solar Business Cards

Inspired by the various existing designs of PCB business cards, we were inspired to make a similar thing for Fablab Digiscope.So far there have been popular business card projects which have had LED patterns display, have miniature screens, Magic 8-ball prediction capabilities, act as MIDI controllers, others bring up a text file on a computer… Continue reading Solar Business Cards

Debugging

  I like to draw out my circuits and then color over the lines after I’ve soldered them or re-checked them. I really enjoyed this overview of electronics debugging made by MIT TA D. Elliott Williams: http://web.mit.edu/6.101/www/reference/TheArtofDebuggingCircuits.pdf Here is a summary of the main thinking as I see it: -Circuits cannot be wrong, if there is… Continue reading Debugging

RF communication with the RFM12B module

  (For the working code scroll all the way to the bottom!) I free-formed a simple RFM12B atmega168 temperature sensor circuit using a 3.7 lithium ion battery I would one day like to solar recharge. Behold!: Notes: DO for Data Out and DI for Data In, from the perspective of the RFM12B. I’m using a… Continue reading RF communication with the RFM12B module

I2C Demo Board Design

  A mockup of the first prototype showing the size and locations of key components and plugs. This project is inspired by the 8-bit computer of Ben Eater (https://eater.net/8bit/) along with the eccentric PCBs of electronics designers like Teennage Engineering and Bastl instruments. I would like to make a board that is didactic and pedagogical,… Continue reading I2C Demo Board Design

Fab15 part III

Finally have something that works and is easy enough to assemble and work with.Here is the radio side: Here are the two sides of the sandwhich: And here is the assembled sandwhich: I also tried, in vain, to solder a few SMD components by hand. First the DRV8838 motor driver. It’s devilishly tiny and despite… Continue reading Fab15 part III

Fab15 part II

Here is the REV.2 board.It’s far more compact, around 38mm x 38mm, and is stackable. The ICSP acts as a connector linking the top and bottom boards, with one extra pin for the Vout from the LTC3105 to the RF transciever. The idea is to use long pins which will pass through the board but… Continue reading Fab15 part II

Fab15 part I

pHere is the video explaining the intention of the workshop: https://vimeo.com/336378467 New idea of using 0ohm jumpers to isolate sub sections of the circuit. This allowed me to test the RF side independent of the LTC3105 side which turned out to be very useful. Took about 5 or 6 passes on the lasercutter, 20 minutes… Continue reading Fab15 part I

Electronics 101

A series of boards and graphic aids to learn about electronics. The main idea here is that each kit teaching some basic principle of electronics, and that it makes the theory portion of electronics more hands on and fun. The kits themselves should be beautiful, so that the students want to keep them, and therefore… Continue reading Electronics 101

Fab 15 part IV

I am using this sensor in the following code:https://www.pololu.com/product/2127/resources // RFM69HCW Example Sketch // Send serial input characters from one RFM69 node to another // Based on RFM69 library sample code by Felix Rusu // http://LowPowerLab.com/contact // Modified for RFM69HCW by Mike Grusin, 4/16 // This sketch will show you the basics of using an… Continue reading Fab 15 part IV

The 1381 Solar Engine

    This circuit (found here: http://solarbotics.net/library/circuits/se_t1_1381.html) works with a MCP112 voltage supervisor to save up solar energy until it is significantly large to make turn a motor. With a small solar panel charging a large capacitor, it is possible to make something move even on an overcast day! The circuit works by charging the capacitor… Continue reading The 1381 Solar Engine

USART

  Elliot Williams’ Make: AVR Programming was helpful for this code. Don’t forget to plug Rx to Tx and Tx to Rx! This is the only protocol I know of where this reversal is important. I am using the Attiny2313 because it is, as far as I know, the only chip in the Attiny family… Continue reading USART

Timers

 In this code I am using an Attiny 84 to produce different frequencies for a piezo buzzer (PB2). The Attiny ADC works a little differently than the Atmega. Essentially, you provide a value for the OCR0A and it will count up to that value and send a high to PB2 when it does. Then it… Continue reading Timers

Serial Peripheral Interface – SPI

  Serial Peripheral Interface requires more wires than I2C, four instead of two, but is easier to implement. The CS line tells the slave that it has been selected, the clock line provides the timing and the MOSI (Master Out Slave In) and MISO (Master In Slave Out) lines each carry one way messages. Unlike… Continue reading Serial Peripheral Interface – SPI

Sleep Mode + Nocturnal Solar Circuits

  I have put my Attiny84 into Powerdown Mode while it waits for a supercapacitor to charge up. Once the solar charging circuit goes low, it turns on an LED until it runs out of juice. With a florescent lamp (not ideal) 10 cm away from a 33x36mm 6.7V panel it took about an hour… Continue reading Sleep Mode + Nocturnal Solar Circuits

Interrupts

 This code will blink an LED while listening for a button press. Not amazingly impressive but difficult to do with Arduino and the delay() function (while the delay macro is executing the microchip is kind of useless and can’t be listening to the state of a button). Be sure to debounce your button in hardware… Continue reading Interrupts

Understanding I2C

  I2C (a.k.a. TWI, 2 Wire Interface) is a communication protocol that can allow your “master” microcontroller to speak to up 120+ “slave” devices. The protocol requires only two wires, one for data (SDA) and the other for the clock (SCL). Each device is connected to the same two wires but each also has a… Continue reading Understanding I2C

EEPROM

  Want to write a value so that you can access it if the microchip loses power and restarts? Write it to EEPROM! The Attiny 24/44/84 family have 128/256/512 Bytes of In-System Programmable EEPROM, so it’s not enormous… The avr/eeprom.h code is from avr-libc, a Standard C library for AVR-GCC. Here’s a link to the… Continue reading EEPROM

Dual Solar Tracking

  Following on from the single axis solar tracker I built recently I would like to make a dual axis solar tracker – but with a twist: I would like one axis to be a set of tank treads. This way one can eventually imagine an autonomous solar powered robot which tracks the sun and… Continue reading Dual Solar Tracking

Button Debouncing

Microchips exist at a different time scale from humans, their electronics “hearts” can beat millions of times a second – think of them as extremely hyperactive brains. Microchip pins can either “listen” (take input) or send voltage signals (output).When in input mode, a microchip pin can detect the state of a button (button pushed, or… Continue reading Button Debouncing

555 signal generator + LM358 op amp + recycled 8ohm speaker

  This circuit is from page 19 of Forrest M. Mimm’s Engineer’s Mini-Notebook : 555 TImer IC Circuits. I am using only a 0.1uF capacitor and don’t have any of the buttons shown in this circuit. This circuit is from page 259 of Learning the Art of Electronics: A Hands on Lab course by Thomas… Continue reading 555 signal generator + LM358 op amp + recycled 8ohm speaker

Attiny Blink

If you have a brand spanking new Attiny84 you’ll need to change the fuses in order to get the timing right. In AVR Studio you can change fuses in the Device Programming Window: #define F_CPU 8000000 // I also disable the CLKDIV8 fuse // #include <avr/io.h> #include <util/delay.h> // because I’m using _delay_ms() // int… Continue reading Attiny Blink

Analog Read

Being able to read values other than 0 or 1 can come in handy! Here I am using the Attiny84 along with a 10K potentiometer. The two ends of the potentiometer are attached to GND and VCC and the middle pin is going to PA1 (ADC1). I have PA0, the ADC reference voltage pin I… Continue reading Analog Read