While browsing one of the numerous "dollar stores" in the area where I live I found this small tester pen. It was kinda nice in yellow metal (might actually be brass) and a protected needle and it seemed large enough for fitting small button cell batteries inside so I bought a few for "future use".
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It seems like it's made for testing if there's 12 volt in the wires in a car since the only part inside the pen is a incandescent bulb. Clip the alligator to some metal and then stick the pointy needle into the wires you want to test.
The lightbulb was for me a completely new model... They have put a smallish bulb inside what looks like a regular 1 ⁄4" x 7 ⁄8" (6.3 x 22.2mm) fuse. Kinda cool, so I though it was worth sharing here. :)
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And yes, button cells of type 392A fits just fine inside the tube. I bought a 10-pack of them for $0.46 at the same store just to test. For that price they probably are just crappy "Onehunglow" quality but how can you manufacture, ship and sell a 10-pack of batteries and still make a profit in all parts of the chain? Strange....
A long while ago I wrote about that I might make a series of boards for easier testing of the open USB stacks. Testing all different version of mcu's and crystal speeds to make the right #defines and linker maps for the firmwares can be a bit tedious.
OSUS will make life a bit easier by removing most of the parts required on the boards to be tested by moving the other parts to this master board. The test-boards basically only need a decoupling cap two and a 14 pin 0.1" pin header - that's it.
On the OSUS master board there's a Reset button and .a extra button to be used for invoking the bootloader or just for general usage. There are also three status LEDs for simple debugging and a connector to a BusPirate LCD adapter for more involved stuff.
The crystal clock speed can be set in 15 steps between 1.25MHz and 48MHz and is provided to the test-board in both 5 and 3.3 volt versions.
Of course there are a ICSP connector and a USB Mini connector on the board as well. It's possible to disconnect the USB D+/D- by removing two jumpers.
All of this on a SOB DP5050 -sized board.
I'll solder up some MCU test-boards for this and give it a spin. I'll be happy to send a presoldered OSUS Master board for free to those who contribute to the Open Source USB Stacks out there.
This is just a small utility board that I added to a previous batch of PCBs. Nothing fancy at all. :-)
Sometimes I need a pot or two when I test a design on a solderless breadboard and it's always a PITA to fit the pots into the breadboard, same thing with switches. So I made the POTONG6 that is a SOB DP8049-sized breakout board with six small (10x10mm) potentiometers and six small slide switches for easy connection to a breadboard.
As can be seen in the picture there's a lot of jumpers on the board. Each pot can have its terminals jumpered to vcc & gnd and only have the wiper connected to the breadboard (good when you only want a variable voltage), or all three terminals can be accessed individually.
Same thing with the switches. Either connected to vcc/gnd via resistors and you only connect the common to the breadboard or remove the jumpers and have access to all three terminals.
This is a small handheld PIC24-based CHIP-8 emulator game console. A cheap Noika 1202 LCD is used as the display and a CR123A 3 volt lithium battery for power.
CHIP-8 is an interpreted programming language, developed by Joseph Weisbecker. It was initially used on the COSMAC VIP and Telmac 1800 8-bit microcomputers in the mid-1970s. CHIP-8 programs are run on a CHIP-8 virtual machine. It was made to allow video games to be more easily programmed for said computers. (http://en.wikipedia.org/wiki/CHIP-8)
The CHIP-8 instruction set only have about 35 instructions and ir very easy to emulate. The full firmware for the MCC8 only took an evening to write.
The sixteen buttons on the right is a hexadecimal keypad arranged in the same strange order as the COSMAC had for maximum keyplacement compability. Then I've added four extra buttons to go into game selection menu mode and other stuffs for future use.
My original plan was to use a PIC24FJ64GB002 (or 004) so I could connect the MCC8 to a PC to upload and debug new games, but by mistake when soldering I populated the board with a GA instead of a GB so the USB functionality is currently not available.
I've added 23 games into the firmware so they can be loaded into CHIP-8 RAM from the menu.
I needed some RCA jacks for an upcoming project so I ordered a bag of 100 from Taobao ($3.61 for 100pcs) but I somehow screwed up the footprint. The silk got rotated 180 degrees compared to the slots and holes so when I used it on a PCB the barrel ended up pointing inwards instead out out from the pcb edge.
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It turned out to be easy to fix. I just twisted the flat leads 90 degrees and by just dumb luck the "structural plastic tabs" on the bottom of the jack is hanging perfectly at the edge of the PCB. :-)
This is a small (10x20cm 4x8") portable battery-operated synth with a two octave touch keyboard and four voice polyphonic digital sound.
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I'm using two microcontrollers on the board - a Microchip PIC18F44K22 for the user interface and a Atmel ATMEGA328 for the sound generation.
The PIC18 is using the internal CMTU module for capacitively sensing the 24 touch keys. It is also in charge of scanning the 15 tactile buttons, refreshing the 15 status LEDs and the 7-segment displays, and polling the Rotary Encoder.
Whenever a keypad is touched or the rotary encoder is turned a standard Note On/Off or Control Change MIDI message is sent to the ATMEGA328.
Currently the ATMEGA328 is running a straight copy of the Midi Vampire-I firmware. The ATMEGA328 is also connected to a SD-card connector for future use.
The sound-generating part is contained in a 5x5cm "selfcontained" area to the right on the pcb having pads and via holes for power, midi and SD-card signals. This makes it easy to replace just the synth with something else than the MidiVamp. Design a new 5x5 cm pcb and solder it to the pads on the main board.
For $6 I get the device and a full set of cables, and some probes. Basically excactly the same thing as I get directly from Saleae for $149- but the clone is of crappier quality of course.
I've been looking at the Saleae for a while but never felt that I have would enough usage to pay $149 so I've stuck the BP whenever I had a need for doing some analyzing.
On one hand it's nice to get some cheap tools, but on the other hand it kinda feels like stealing the food from the table of the Saleae guys who has put in a lot of thought and work hours for the design and software - especially the software. They're probably doing just fine anyhow with popular a $149 product, but still.....
So what should I do? Send them $25 for the (free) software and say "Thanks guys"? Or just a postcard maybe? Personally I'd appreciate a postcard more than $25 into the company account. There should be some kind of "thank you - have a beer coupon" that you can send to people.
I recently received a gift coupon from Seeed and as a loyal DP subject I bought a bunch of items from DP for it. :-)
1 x Bus Blaster v3 1 x Bus Blaster v3 acrylic case 1 x Bus Pirate Cable 3 x Sick Of Beige Basic Case (DP5050) 3 x Sick Of Beige Basic Case (DP7043) 3 x Sick Of Beige Basic Case (DP8049) 2 x Sick Of Beige Basic Case (DP5031)
Thank you for the coupon Seeed, and thank you Ian for making cool stuff....
I've been a bit busy the last couple of weeks but I've now finished my 22'nd Project A Week. Maybe I have to change the name to PAAW instead (Project Almost A Week) ^_^
TraId is a really low cost version of the Part Ninja. It's made to only identify the pinout and type (NPN/PNP) of a transistor and display the results on eight LEDs. Currently the firmware only handles BJTs but I think FETs should be possible as well.
The board is using a 14 pin PIC16LF1503 (less than a dollar in singles) and runs on a single CR2032 battery. Just like the Part Ninja I'm using a 1K and a 300K resistor connected to each of the three transistor pins, putting out either 0 or 3 volts via the resistors and analyzing the resulting voltages using the PIC ADC.
The firmware, written in C, uses 1.3K of the available 2K so there's room for some more additions and improvements down the road.
There's no powerswitch on the board, the PIC simply goes into deep sleep after a while and is awakened by a press on the reset button.
All parts are thru hole for easy soldering if I decide to make this into a kit some day.
As PAW18 I did a simple PCB with just a few 1206 parts to be used as a SMD soldering practice board. This week I'm continuing on that theme but for people with a bit more SMD experience.
A 8-pin SOIC is about the easiest SMD IC to solder so I had to come up with a project using one of those, and also not having too many other parts. Since I'm selling my stuff at Tindie I figured that it could be fun to use their logo as the outline of the PCB. The logo have three colored dots on it - a nice fit for three LEDs. https://www.tindie.com/developers/
So I basically just copied the schematics, replacing the Tiny85 with a Tiny45 and also changing the RGB led into three separate LEDs. The pcb is hooked up to a computer via USB and can be used exactly like a Blink(1) for showing status of your server/mail/twitterfeed or anything else.
I must admit that not much original though went into this PAW, but I like it anyways :)
I happened to pass by the stall that does custom made stamps and stickers in my mall and couldn't resist the urge to get some stickers made for me. (20x30 mm / 0.8x1.2 inch in size)
This weeks PAW is something that I have wanted to have for a long time but never gotten around making - until now that is :-)
Everytime I solder a SMD LED on a pcb I have to turn on one of my multimeters and flip it over to diode-test mode and then probe the SMD LED to see which connector is the anode and which is the cathode. The LEDger is a small PCB with a button cell battery and smd footprints that allows me to, while still holding the LED in my tweezers. just hold it onto one of the footprints and see if it lights up or not.
While I was at it I added some other footprints both for SMD and thru-hole LEDs to make the board a bit more universal. The PLCC6 footprint might save me some trouble testing a roll of RGB leds that I bought from eBay where about 30% was BBB instead of RGB :-(
