The Do It Yourself relay

When you are designing a PCB, there are always basic questions and important point to take care. Some example:
- how to convert mil to mm or AWG to diameter ?
- what is the real rendering or appropriate size for text or silkscreen line ?
- what is the maximum current for a specied trace width or via diameter ?


It always take long time to find the right information in the appropriate document.
In order to save time, I created a memento PCB to summarize most important information. This is a great and indispensable tool for every regular PCB designer.

On this board, you will find:

• common SMD footprints (RLC, Diode/Transistor, integrated circuit)
• common connector pitchs
• common via drill diameters with the corresponding maximum current
• sample of copper trace width (in mill and mm)
• sample of silkscreen line width
• sample of silkscreen text font and ratio
• conversion tables (inch/mm, mil/mm, oz/gr, oz/um)
• table of copper trace width Vs. maximum current
• table of copper trace voltage Vs. min clearance distance for functional isolation
• a simple metric ruler (0-8cm)

Here is the 3D gerber rendering of the PCB:


And photos of panelized board and final result:

Download here the poster Datasheet

If you are interested in this reminder tool, I sell some pieces on my Tindie shop:

Presentation

For quite a long time, I am thinking about making a photography programmable remote for my DSLR camera Canon 450D (reflex). This remote should have a simple remote mode and an intervalometer mode (or Time Lapse mode). In this latter mode, the user just have to set the time interval between each photo and the remote will automatically shoot at this frequency. When assembling photos one after the other, you get a kind of video clip. Time lapse mode is mainly used to present long action in few second such as the life of a flower, the melting down of snow, cloud movement in the sky, etc ...

Interface with the camera can be made with an IR LED (if your camera got an IR receiver, lucky you!), or second option (easiest) with a jack cable plugged on the remote port of your camera. Cable connexion can change according to the camera model, but in most of cases, there are 3 wires: 1 wire for common, 1 wire for the focus and 1 wire for the shoot. So, you just have to short circuit the common wire with the focus and/or with the shoot one. That is all !
To control these connexions with some electronics, it is possible to use relays or transistors. Relays are safer than transistor thanks to the voltage isolation between electronics and camera. However, transistors are cheaper and smaller, that is why I chose this solution. To simplify electronics, I wired the focus and the shoot cable together. This mean I will not be able to control the focus independently. But it doesn't matter because I prefere to set manually the focus directly from my camera before starting shoot.

Hardware

Now let's talk about input commands. To set the time interval, it is possible to use some potentiometers and on/off switch. We could imagine a simple electonics with few resistors, capa, potentiometers and a NE555 to generate a signal with a specific frequency. In this project, I wanted something more complete, with different modes and an important range of use for Time Lapse (understand an important range of frequencies). That leads me to choose a solution with a microcontroller and a small LCD screen (it is more "friendly-user" than potentiometer and switch !). After selected the components, I design the following simple schematic:

Bill of materials:

• 1 uC 16f690 : Free (thanks to MicroChip samples)
• 1 Pickit2 (or other programmer) : ~20€ (already got for previous project)
• 1 shield with LCD HD44780 2*16char and 5 buttons : 8€ (available on DX.com)
• 1 NPN transistor (2N3904) : ~0.3€
• 1 voltage regulator (LM7805) : ~0.6€
• some resistors and capacitors : ~1€
• 1 drilled proto-board : ~0.5€ (ebay)
• 1 Battery 9V: 1€
• 1 Battery clip: ~0.5€
• 1 Switch: ~0.5€

For the LCD, I chose a chinese copy of an LCD shield for Arduino. It is cheap and easy to use (no worries about contrast potentiometer for exemple, which is always a source of problems). The LCD is slodered in 4Bits mode, which mean only 7 pins are requiered to controll it (4 data + RS + Vcc + GND). Some links to understand how to use LCD in 4 bits mode: link1, link2, link3. In addition of the LCD, the shiled has 5 boutons (left, right, up, down, select). These buttons are in serial, and realize a voltage divider depending of which button is pressed. This means that, by connecting the buttons pin to an ADC of the microcontroller, we got 5 buttons which need only one pin of the microcontroller. Finally, the shield also has an hardware Reset button.

Solder it !

Once you got all components, it's time to solder all the thinks !
Because this project is just a protoype, I did not want to design a real PCB. Instead of that, as use wire wrapping technics to get quick results.

Software

Concerning the software, I used MpLab 8.86 and the compiler Hi-TECH PICC to program a small 8bits microcontroller (16f690). I use the free version of the compiler so the code optimisation is not available. This is why the software finally fill near the all flash space (4Kword) of the micro (and also because I wrote an heavy duty function with dirty multiplication and division to convert long number to a string (not proud of that :) ).
I coded two different usage modes: the remote mode and the TimeLapse mode.

• The remote mode: use it as a simple remote for camera. Press the SELECT button to shoot. Escape the mode to the main menu with LEFT or RIGHT button. It is also possible to use this mode when your camera is in "Bulb mode" with a "shoot until press" function. This is very usefull to take pictures with an espacialy long exposition time, for exemple for "LightPainting", photos of storm, etc. Keep press the SELECT button to shoot. Release the button to stop the shoot.
• The TimeLapse mode: use it to automatically shoot with a defined interval (from 1 to 3600sec) during a defined delay (from 1 to 3600 min). The screen displays in real time the number of taken pictures. This mode automatically return to the main menu at the end of the delay or by pressing LEFT or RIGHT button.
  

The final product in a (temporary) project case, and a video of how it works (in French):

About the autonomy

I measured a consumption of approximatively 40mA under 9V (360mW). So with a standard 9V battery (PP3) of 450mAH, I should be able to shoot during more than 11Hours. I good practice should have to desactivate the LCD after some time without push button (and switch the microcontroller into low power mode.

Making video clip

To convert all your photos into a video clip, use one of the lots of photos to video software. I tried some, but the only one I should advise you to try is the weel know VirtualDub. It is very easy to use for TimeLapse conversion and the advantage is that you totally control the video size, Bps, frame, codec, and other options. Have a look on this tutorial on timelapseblog.com

Here are some videos shot with my TimeLapse remote:

Conclusion

Finaly, I put the card with the battery in a plastic project box. For the future (soon, I hope), my goal is to design of cover for this box and print it with a 3D printer. As a next step, I also project to add one or two step motors to slowly move the camera during time lapse shooting (camera glider). This will add a cool moving effect (have a look on some youtube videos). Adding motors means additional software code and as I fill all the Flash space of the 16f690, I will have to adapt the project for a bigger microcontroller...

Download

You can download here the complete archive of this open source project.

Note for lazy people: If you are not enought patient to build a such remote, you can directly use a laptop with a time lapse software. Connect your camera to your computer and software will trig the photo shots. An other way, if you have a tablet, Ipad, Iphone or some other Android device, you can also use a TimeLapse Apps with an IR Led pluged on the jack audio output to control your camera.

Je fournis ici quelques programmes avec des fonctions de base pour pic16f690 qui pourront vous servir pour débuter vos projets.

Je présente ici mon second projet scolaire à caractère industriel, réalisé à l'UTBM en 2011. C'est un projet de domotique, beaucoup plus ambitieux que le 1er. Notre groupe était constitué de quatre étudiants ainsi que moi même au poste de chef de projet.

La fainéantise est vilain défaut mais qui peut parfois vous faire gagner du temps. C'est dans cette optique que je vais me contenter d'ajouter quelques photos et de citer l'article suivant écrit par un ami qui a (amplement) participé à la réalisation de ce projet assez complet (conception électronique, réalisation du totem en bois et peinture).

Source: logicien-parfait

Le Raoul est le nom donné traditionnellement au réceptacle à capsule du foyer de l'association des étudiants de l'UTBM. Chaque année, c'est à la promo sortante d'en fabriquer un nouveau, à l'effigie de son logo, soit pour la promo 8, un bonhomme de neige.

Partie électronique

Je me suis joint au projet pour la partie électronique : le compteur de capsules. Malgré le domaine GESC de l'UTBM, ce n'est que le 4éme Raoul à avoir un compteur électronique. Mieux encore, il est le seul à avoir été un minimum opérationnel dès sa mise en place. La seule correction effectuée depuis est la désactivation de la détection quand le stroboscope est en marche. En effet la détection étant faite par des faisceaux infra rouge, la lumière du stroboscope, trop puissante déclenchais parfois un double comptage. Fonctionnement

Dans un premier temps, les capsules sont détectées par deux faisceaux infra rouges (led + détecteur) faisant une croix, à travers un tube de PVC. Le tube est assez grand pour faire passer des bouchons de champagne, mais alors laisse des espaces suffisants pour que certaines capsules passent sans se faire détecter.

Grâce à deux AOP en comparateur, on génère une interruption sur le microcontrôleur. Celui-ci compte, met le nouveau total en eeprom, et lance l'animation de comptage. Soit, faire défiler de haut en bas les chiffres qui doivent être changés (et seulement eux !).

De plus, toutes les 2 minutes, si aucune capsule n'a été détectée, une animation aléatoire se lance.

   - Changement rapide des couleurs des 5 LED RGB (individuellement contrôlées)
   - Défilement d'une phrase parmi celles en mémoire
   - Allumage quelques secondes du stroboscope

L'afficheur a été fait séparément, il comporte 4 registres à décalage avec latch. On affiche une ligne à la fois, et un timer fait changer cette ligne. La carte commande ayant été fait plus tard, et embarquant un microcontrôleur ATmega168 (arduino compatible), tout le code de gestion de l'afficheur a été prototypé sur un arduino. Fichiers

Voici les circuits : carte commande matrice de led

Ainsi que l'ensemble des fichiers du projet. Cette archive comprend les prémices de mon générateur de caractère qui permet de créer facilement les définitions des caractères.
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Photos de construction et mise en place

Le tout dans la traditionnelle ambiance festive du Père 200

Et quelques mois plus tard ...