Mooshimeter: The ‘Why Didn’t I Think Of That’ Multimeter

Despite how useful multimeters are, there are a lot of limitations you just don’t think about because they’re the way electronic measurement has always been done. Want to measure voltage and current simultaneously? Better get two meters. Measuring something in a dangerous, inaccessible, or mobile place? You could rig up a camera system to show the meter’s display on a monitor, you know.

Mooshimeter is the better way of doing things. It’s a multichannel multimeter that communicates with your cell phone over a Bluetooth connection. With two channels. the Mooshimeter makes it easy to graph voltage against current to plot a beautiful IV curve on your smart phone.

Being a wireless multimeter means you can stick the Mooshi inside a robot and get instantaneous feedback of how hard you’re driving your motors. Far from being a two-trick pony, the Mooshimeter is actually a pretty good multimeter by itself. It can handle 600V and 10A with 24 bits of resolution. Here are the complete specs. The Mooshimeter is available for preorder here for $100 USD.

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JTAGulator Finds Debug Interfaces

[Joe Grand] has come up with a tool which we think will be useful to anyone trying to hack a physical device: The JTAGulator. We touched on the JTAGulator briefly during our DEF CON coverage, but it really deserves a more in-depth feature. The JTAGulator is a way to discover On Chip Debug (OCD) interfaces on unfamiliar hardware.

Open any cell phone, router, or just about any moderately complex device today, and you’ll find test points. Quite often at least a few of these test points are the common JTAG / IEEE 1149.1 interface. JTAG interfaces have 5 basic pins: TDI (Test Data In), TDO (Test Data Out), TCK (Test Clock), and TMS (Test Mode Select), /TRST (Test Reset) (optional). If you’re looking at a PCB with many test points, which ones are the JTAG pins? Also which test points are which signals? Sometimes the PCB manufacturer will give clues on the silk screen. Other times you’re on your own. [Joe] designed the JTAGulator to help find these pins.

The idea is simple: Connect the JTAGulator to the test points on the PCB under test, issue a few commands via a serial terminal, and let the JTAGulator do the rest. It performs a brute force approach on every permutation of pins, issuing basic JTAG commands – either IDCODE or BYPASS, and looking for a response. If any valid responses are received, the JTAGulator displays the found interface’s pinout.
[Joe] used a Parallax Propeller as the core of his design.

He added input protection, selectable voltage (1.2V to  3.3V) and bus pirate compatible headers. The JTAGulator can also identify and test serial UART pinouts to determine if any serial ports exist. If JTAG and serial aren’t enough, the JTAGulator is completely open source, released under the CC BY 3.0 US license. You can add any interface you want.  Though [Joe] has plans to add more of the common interfaces in the future.

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A FPGA Controlled Reflow Oven

For Christmas, [Hamster]‘s wife gave him a mini-oven. Later that day, he tore it apart and built this FPGA controlled reflow oven. We’ve seen plenty of reflow oven builds in the past. Most of those projects use a microcontroller to do closed loop control, sensing the temperature and toggling the heating element to hit a set point. This build uses the Papilo One FPGA development board as a controller. It implements a state machine that meets the reflow profile of the solder paste, ensuring SMD components are soldered properly.

The oven uses a MAX31855 to read temperature from a thermocouple. This device provides amplification, cold junction compensation, and analog to digital conversion which spits out the temperature over SPI. To control the heater, a 40A solid state relay is used. The VHDL code that drives this oven is linked in the writeup, and has some interesting bits for those looking to experiment with FPGAs. It includes an SPI interface, display driver, and the temperature state machine logic.

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