4Duino UCAM-II Demo


by 4D Systems @ instructables.com:

The main objective of this project is to show how to interface a uCAM-II serial camera to 4Duino. uCAM-II is a highly integrated micro serial camera which could be controlled by any host that requires a video camera or a JPEG compressed still camera for embedded imaging applications. uCAM-II processes various features making it trivial to interface to a microcontroller. Following are the list of few features to help you understand the module better.

4Duino UCAM-II Demo – [Link]

OPT3002 – Light/digital IC provides optical power measurements

By Graham Prophet @ edn-europe.com:

Distributor Mouser Electronics has Texas Instruments’ OPT3002 light-to-digital sensor; the device promises improved system performance over standard photodiodes and photoresistors. The fully-integrated OPT3002 delivers the functionality of an optical power meter all within a single small device.
Offering a wide spectral bandwidth, flexible and automated light measuring over a 23-bit effective dynamic range, and a simplified software and set-up configuration, this low-power optical sensor is suited for use in optical spectral systems that require detection of a variety of wavelengths, such as optically-based diagnostic systems, or even as a low-power, battery-operated wake-up sensor.

OPT3002 – Light/digital IC provides optical power measurements – [Link]

A DIY obstacle avoiding robot using an SG90 servo and Ultrasonic Sensor

In this video educ8s.tv shows us how to build an Arduino Robot that can avoid obstacles:

The robot that we are going to build today is moving around and it can detect obstacles and avoid them. It uses a supersonic distance sensor in order to measure the distance from its front side. When it detects and obstacle it stops, goes backward for a few cms, looks around and then it turns to the direction with the more space available. As you are going to find out, building this impressive little robot is extremely easy and fun. It will not take you more than a couple of hours from start to finish. Then you can use my code, modify it and implement your own robot behavior easily. It is a great learning experience and great introduction to robotics for kids and adults. Let’s build it!

A DIY obstacle avoiding robot using an SG90 servo and Ultrasonic Sensor [Link]

PV cell string optimizer boosts solar panel output up to 30%

Maxim presents its Cell-String Optimizer as the first IC to perform MPPT (maximum power point tracking) at low level in a panel; it allows photovoltaic (PV) panels to harvest significantly more energy and simplifies design complexity for solar installation projects. by Graham Prophet @ edn-europe.com

Maxim’s cell-string optimizers are highly integrated DC-DC converters that replace the bypass diode and perform maximum power point tracking (MPPT) deep inside the PV module. By replacing each diode with a MPPT device, the on-off response to performance mismatch is eliminated; every cell-string contributes maximum power without interfering with the power production capability of others. This enhanced degree of flexibility leads to increased energy production; eliminating collateral performance loss due to module mismatch, degradation, soiling, localized shading, and row shading loss mechanisms.

PV cell string optimizer boosts solar panel output up to 30% – [Link]

LTC7851 – Quad Output, Multiphase Step-Down Voltage Mode DC/DC Controller with Accurate Current Sharing


The LTC7851 is a quad output multiphase synchronous step-down DC/DC controller with accurate current sharing between phases and differential output voltage sensing. This controller works in conjunction with external power train devices such as DrMOS and power blocks as well as discrete N-channel MOSFETs and associated gate drivers, enabling flexible design configurations. Up to 8 phases with two ICs can be paralleled and can be clocked out-of-phase to minimize input and output filtering for very high current requirements up to 260A. It operates with a VCC supply voltage from 3V to 5.5V, is designed for step-down conversion from an input voltage from 3V to 27V and produces one to four independent output voltages ranging from 0.6V to 5V. The device’s voltage mode control architecture allows for a selectable fixed operating frequency from 250kHz to 2.25MHz or it can be synchronized to an external clock over the same range. Applications include power distribution and industrial systems, FPGA, DSP, processor and ASIC supplies.

LTC7851 – Quad Output, Multiphase Step-Down Voltage Mode DC/DC Controller with Accurate Current Sharing – [Link]

How Boost Converters (DC-DC Step-Up) Works

A look into how boost converters work in a very visual format. Try this circuit: http://goo.gl/nkHq9H

How Boost Converters (DC-DC Step-Up) Works – [Link]


Driving 14-segment displays with the MAX6954


App note from Maxim on using the MAX6954 to drive 14-segment monocolor LEDs, (PDF):

This article is how-to guide, intended as a quick learning aid for engineers considering using the MAX6954 to drive 14-segment monocolor LEDs.

The MAX6954 is a versatile display driver, capable of controlling a mix of discrete, 7-segment, 14-segment, and 16-segment LED displays through a serial interface. This application note shows a typical application and configuration for driving eight mono-color, 14-segment LEDs.
See the MAX6954 data sheet for additional information about MAX6954 features.

Driving 14-segment displays with the MAX6954 – [Link]

Cheap Arduino Serial Terminal


Peter Scargill writes,

As it happens I’m experimenting on a 1284 chip which while being Arduino-compatible kind of, it does have another serial port, so without disconnecting my FTDI – I hooked up the second serial port to the home control serial and fired the DEBUG command at the latter.
As you can see on the left, a perfectly usable terminal. At this point despite YEARS of VT-100 wilderness I’d mastered the colours and scrolling area controls – thanks to this handy VT-100-related link. Not all of the commands work and in order to make a character counter I had to do a custom colour save.”

Cheap Arduino Serial Terminal – [Link]

Using A Bench Power Supply To Charge Lithium Ion Batteries

David Jones has another useful video tutorial about how to safely charge Lithium Ion and Lithium Polymer batteries with a bench power supply. The purpose of this tutorial is to learn how to use your lab power supply to charge your Lithium Ion battery when you don’t have a special charger circuit to do so.


He used NCR18650B in his tutorial, a 3.6V 3400mAh Lithium Ion battery from Panasonic.
David warned us that charging this type of battery is quite dangerous if we didn’t do it in the correct way. Even with the presence of protection circuit in Lithium Ion battery.


You can find the charging diagram in NCR18650B battery datasheet.


According to the datasheet, the charging current is 1625mA and the charging voltage is 4.2V. Charging consists of two stages, first one is the constant current stage where you must supply a 1625mA constant current and when the battery voltage reaches 4.20V, the second stage starts, which is the constant voltage stage. In this stage, the current will naturally drop down, and the cutoff is typically about 10% of charging current so it’s about 170mA.
This tutorial applies to all Lithium Ion and Lithium Polymer batteries not only NCR18650B.


You can perform this 2-stage charging using your power supply, but it must supports CC(Constant Current) and CV(Constant Voltage) modes. You can read the following Q&A in electronics.stackexchange to learn what constant current and voltage modes mean. You can build a power supply with CC and CV modes for yourself if you don’t have a budget to buy a ready made one.

David’s Power Supply Setting With 4.2V CV and 1700mA CC
David’s Power Supply Setting With 4.2V CV and 1700mA CC
The Battery Charges in The First CC Stage Sinking 1698mA
The Battery Charges in The First CC Stage Sinking 1698mA

David said that using this type of float charging/trickle charging is not recommended, because it will build-up or plate the metallic parts inside the battery. So It’s better to use dedicated ICs designed for the float charging.

David mentioned in his video that a complete tutorial is available for whom who want to know in details how to charge lithium ion battery.


Exploring Eagle CAD ULPs #2 – ‘Unrouted.ULP’ Zoom To The Last Left unrouted Wire

Welcome to the second post of the “Exploring Eagle CAD ULPs” series. Every week we will publish a new post about one useful ULP in Eagle CAD.

“ULP” User Language Program is a plain text file which is written in a C­-like syntax and can be used to access the EAGLE data structures and to create a wide variety of output files. You can consider it like a plug-in for Eagle.

You can reach the posts published in this series using the following link.


In this post we will discover “Unrouted.ULP” by Daniel Mack. The job of this ULP is to zoom to the first unrouted wire in the board editor. This might be helpful when searching for tiny leftover air wires especially in big boards.
When we use ‘ratsnest in layout editor, a result with remaining airwires is shown in the bottom of the editor. Sometimes airwires are not visible to our eyes and need a lot of searching.

One Airewire Is Left - See the red circle
One Airewire Is Left – See the red circle

“Unrouted.ULP” can zoom to unrouted line and solve this problem for us.

You can see this ULP in action in the below GIF


You can download the ULP from here: Unrouted_ULP

That’s all for this time, see you next post in this series!