XS Boost, A Chef's Salad Solar Robot Like most robot builders, I tend to accumulate interesting parts and experimental concepts that never end up being necessary in an ordinary robot design. So, every once in a while, I build a robot without a purpose just to try out a bunch of new pieces and reduce the pile. XS Boost is a chef’s salad robot -- a hearty combination of things that were lying around. Left: XS Boost compared to an ordinary soft drink can. The robot is actually more difficult to photograph than it might seem. Vital Statistics Base Dimensions: 9 cm width x 9 cm length x 7 cm height (excluding sensors and solar cell) Total Mass: 181 grams Power Source (solar): 5.5 V (open circuit) 30 mA (short circuit) 37 mm x 66 mm solar panel Power Source (battery): 2 x 1.2 V N-cell NiMH rechargeable Speed (solar): 1.5 cm/s (swapped gears, in summer, sunny), 0.24 cm/s (as pictured, in sunny winter) Speed (battery): 6.30 cm/s Left: XS Boost overhead / head on. Solar Cell Sensors Part: Siemens BPW-34 1/8in. square solar cell. Movies
Power Smart Heads - BEAM Robotics Wiki From BEAM Robotics Wiki The power smart family of head designs spring from a simple battery-powered design by Wilf Rigter. Unlike simple bicore heads, Power Smart Heads turn off their motors when they are centered on the light source they are tracking. Consequently, they do not waste the energy that bicore heads do as a result of the fact that bicore heads oscillate when they are centered on the light source. Hence power smart heads operate more efficiently than bicore heads.  Original Version Wilf's original Power Smart Head article BEAM Heads 101 contains a complete explanation of his original design, but he recently posted this explanation of its workings: The PD1 / PD2 photobridge acts as a voltage divider with the midpoint at Vcc / 2 when the light on each PD is equal. The hi / lo oscillator uses R1 / C1 to set the basic frequency. With an R1 to R3 = 10 to 1 ratio, the frequency and the duty cycle varies when the PD output voltage is within 10% (+ / -) of the threshold.
Miller Solar Engine - BEAM Robotics Wiki From BEAM Robotics Wiki Probably the smallest incarnation of the Miller SE, using SMD pieces On December 18, 1999, Dave Hrynkiw announced on the BEAM Email List that Solarbotics had licensed the Miller Solar Engine from Andrew Miller of "AM Innovations".  Introduction The Miller solar engine (also called Millerengine) uses a 1381* voltage detector (a.k.a., a voltage supervisor) IC to drive a voltage-based (type 1 solar engine) solar engine. The Miller SE is designed to increase the 1381 hysteresis to a larger value. Here's the basic circuit (It is shown as a modification to the "vanilla" 1381 SE circuit, where added components are red, deleted components are grayed out, and common components are in black):  How it works As the solar cell charges the (4700 uF) storage capacitor, the voltage across the capacitor increases with time. By choosing values for C1 and R1, we can "tweak" the performance of this circuit.  Freeforming  Calculating the 1381 Voltage
Solar Charger 200ds230 rev2 Note, a newer version can be found here. An unconventional, scalable high efficiency 12V solar power system and battery charge controller with low voltage cutout to protect the battery. (ideal for systems of 50W or less) Low idling currentThis circuit was designed for small to medium lead acid systems and feature a lowish idle current ( 5mA ) which increases battery life on small capacity systems. Easily obtainable partsAll the parts in this design are through hole parts and can be found from a number of sources. Late generationThis is the 3rd iteration of the design, with improvements and bug fixes at every step. Some of the older, development revisions : Regulation The solar controller uses shunt solar regulation, when battery voltage exceeds a set voltage, typically set to 13,8V. Low voltage battery protectionThe circuit disconnects the battery if the if the battery voltage drops below an adjustable point, typically 10.5V. An exampleAssuming you are paying 3$ / Watt for your panel.
Faraday For Fun: An Electronic Batteryless Dice There has been a lot of interest in muscle powered electronic devices, due in large part to the success of Perpetual TorchPerpetual Torch, also known as battery-less LED torch. The battery-less torch consists of a voltage generator to power the LEDs, an electronic circuit to condition and store the voltage produced by the voltage generator and high efficiency white LEDs. The muscle powered voltage generator is based on Faraday's law, consisting of a tube with cylindrical magnets. This Instructable shows you how to build an electronic, batterless dice. But first some background --->
Using a Small Solar Cell and a Supercapacitor in a Wireless Sensor July 1, 2010By: Pierre Mars, CAP-XX (Australia) Pty. Ltd.Sensors Here's how supercapacitors—double-layered capacitors with the ability to store far more energy that a traditional capacitor—can be used in conjunction with a small solar cell to power a wireless sensor node. Wireless sensor networks (WSNs) are becoming more common. They solve problems in many applications, some of which can harvest solar energy to use as a limitless, battery-free energy source. However, small solar cells are very low power, delivering milliwatts of energy. What Are Supercapacitors? CAP-XX supercapacitors benefit from a nanotechnology construction that packs the highest energy and power densities into thin, prismatic packages that fit space-constrained devices. Supercapacitors as a Power Buffer Before there were low-impedance supercapacitors, designers had to size the entire power supply system for the load's peak power. In our example, the average load power is 0.75 mW. Low leakage current. Aging. where:
Simple DC-DC converter with design tool The MC34063A is an easy to use DC-DC converter that can be used to step battery voltage up or down to run your processor, small servos or to make an efficient LED spotlight. The photo shows a kit I bought from Oatley Electronics using this IC and has parts for stepping up or down on the one board. In the photo I'm driving 6x0.5W 10mm LEDs from two AA batteries (3V). This kit is set up to regulate current by regulating the voltage across a shunt resistor but only minor modification is needed to use it as a 5V regulator. The Datasheet also has several sample application circuits complete with board layouts that can step up or down or even invert to supply a negative voltage rail for opamps etc. Best of all, I've found a simple design tool that displays the apropriate schematic and calculates component values for you. You will need soldering skills to assemble the kit otherwise just get the components from your local supplier and breadboard it.
Unusual Components and Applications - WorkbenchFun.com Negisters, Unijunction transistors, Precision Resistors, and Hall Effect Devices Nothing has impacted our lives more than the electronic devices we now use in our everyday lives. More and more, sophisticated devices are becoming commonplace and research is constantly adding to the list. Negistor One of the most unusual devices in electronics is the negister. In the diagram we see a capacitor across the transistor charges until the reverse breakdown voltage is reached. Amazingly, the circuit is extremely stable and produces a linear ramp wave. White Noise Generator The avalanche mode can also be useful in the production of white noise. Unijunction Transistor One of the most unusual solid state devices is the unijunction transistor. In the unijunction circuit capacitor C1 charges through resistor R1. Capacitor C2 charges through resistor R2 and is discharged at the same time as capacitor C1, producing a negative pulse. Precision Resistors Hall Effect Hall Effect Sensor Alarm Conclusion
Super Capacitor in solar power supply - a few queries I intend to build a remote 'weather station' The station will: Be completley independant of any external power, ie, it will produce its own power via solar cell(s)Measure temperature onlyTransmit its finding over an RF link to an indoors reciever Instead of using a rechargeable battery supply with charger circuit, i have decided to use a 35F, 2.7V super capacitor to smooth and store power. The power scheme will run along these lines: Panel Array* ===> Diode ===> Super Cap ===> Voltage boost to 5V via pololu voltage boost ===> Remainder of circuit *The output voltage will preferably be ~1.5V, as my super cap is rated at 2.7V and i hear a general rule of thumb is to keep the impressed voltage at around half the rating for long capacitor life. I have several questions concerning this setup: How can I ensure that the total power output by the panel(s) and capacitor will not cause the voltage boost (and subsequently my logic circuit) to "hiccup." If so, how can I prevent it? Thanks all!
Boost DC-DC Voltage Regulator Converts To Current Source for Battery Charging Abstract: A boost DC-DC controller built with the MAX1771 DC-DC controller makes a simple switch-mode current source that is useful for battery charging. The voltage control loop is disabled so that the current control loop provides regulation. The switching regulator of Figure 1 includes independent loops of current and voltage feedback for maintaining regulation. By disabling the voltage loop, you can use the current loop to implement a general-purpose current source. Figure 1. First, apply 5V to V+. Figure 2. With the proper component values, the circuit generates constant current over a wide range of input voltages. The peak inductor current is IPEAK = VSENSE/R1, where VSENSE is the 210mV threshold of the current-sense comparator. (1) IDITHER = VBATT tOFF/L, where VBATT is the battery voltage, tOFF is the 2.3µs interval mentioned earlier, and L is the inductance of L1. As illustrated in Figure 2, the average inductor current is IAVE = IPEAK - ½IDITHER. (Use L = 100µH.) Figure 3.
Pololu Adjustable Boost Regulator 4-25V This powerful, adjustable boost regulator can generate an output voltage as high as 25 V from an input voltage as low as 1.5 V, all in a compact, 0.42″ x 0.88″ x 0.23″ package. A trimmer potentiometer lets you set the boost regulator’s output voltage to a value between 4 and 25 V. Overview The Pololu adjustable boost regulator is a very flexible switching regulator (also called a switched-mode power supply, SMPS, or DC-to-DC converter) that can generate voltages higher than its input voltage. We offer two adjustable ranges: approximately 2.5 V to 9.5 V and 4 V to 25 V. Some example applications include: Powering 5 V or 3.3 V systems from lower-voltage batteries Powering 5 V subsystems (e.g. sensors) in lower-voltage (e.g. 3.3 V) systems Achieving consistent actuator operation when powered by fluctuating batteries Powering high-brightness LEDs or a large number of LEDs in series Feature summary Using the Boost Regulator Connections Setting the output voltage LC Voltage Spikes
Boost converter A boost converter (step-up converter) is a DC-to-DC power converter with an output voltage greater than its input voltage. It is a class of switched-mode power supply (SMPS) containing at least two semiconductors (a diode and a transistor) and at least one energy storage element, a capacitor, inductor, or the two in combination. Filters made of capacitors (sometimes in combination with inductors) are normally added to the output of the converter to reduce output voltage ripple. The basic schematic of a boost converter. The switch is typically a MOSFET, IGBT, or BJT. Overview Power for the boost converter can come from any suitable DC sources, such as batteries, solar panels, rectifiers and DC generators. ) must be conserved, the output current is lower than the source current. History Switched systems such as SMPS are a challenge to design since its model depends on whether a switch is opened or closed. Applications The NHW20 model Toyota Prius HEV uses a 500 V motor. and
Power Supply 5v Solar/TITLE> HOW THE CIRCUIT WORKS The circuit consists of an oscillator transistor and a regulator transistor. The solar panel charges the battery when sunlight is bright enough to produce a voltage above 1.9v. A diode is required between the panel and the battery as it leaks about 1mA from the battery when it is not illuminated. The regulator transistor is designed to limit the output voltage to 5v. This voltage will be maintained over the capability of the circuit, which is about 10mA. The oscillator transistor must be a high-current type as is is turned on for a very short period of time to saturate the core of the transformer. AUTOMATIC The circuit can be made automatic by adding a 1k resistor and diode: Automatic Solar Power Supply Circuit The oscillator will turn off when the output from the solar panel is above 1.3v and although the circuit does not shut down to zero current, it consumes about 3 mA, while the shut-off circuit takes about 1mA. Low Current Power Supply Circuit