Self sustaining solar powered charging platform

When deploying remote electronic device there is always a dilemma how to power it. You normally want to provide long therm power source and if it can recharge during operation, then things are even better. If you are thinking on building embedded project outside, then you should consider using renewable power sources like sun and wind. SwitchDoc Labs has been working on handy platform that helps achieve a bit of power independence. Their main focus is to provide solar tracking for small solar panel which can charge batteries, power embedded boards like Raspberry Pi or Arduino, and report parameters to apps. So called “SunAir” have everything you need to deploy independent system which takes care of tracking sun with two photo-resistors, servo motor and limit switches. Solar charge controller ensures that proper backup battery recharge. Level booster provides 5V to power Raspberry Pi or Arduino that can monitor “SunAir” parameters and send them through network to remote app. The rest is up to you how much reliability you want. If your project is energy hungry, then add more backup battery… Continue reading

Raspberry Pi power supply with backup solution

Raspberry Pi basically runs on Linux which takes time to start once powered. If you have designed some hardware solution which controls valuable things, you probably don’t want it to fail on power failures. Like for desktop computers there UPS used, same technique can be applied to Raspbbery Pi. The only difference is scale of things. Juice4halt shares Raspberry backup power solution. He uses couple supercapacitors for energy storage. Since supercaps are low voltage like 2.7V there is step-up/down circuit needed to take care of charging and draining power. He made whole power board that sits on top of Raspberry Pi. It carries two independent Ds/Ds converters where on is used for charging supercaprs in step-down mode and powering board from them through step-up converter. Another DC/Dc converter is used as front end step-down converter which converts input voltage in to 5.1V. This is convenient for using any wall DC adapter. With two 25F 2.7V supercaps and 375mA constant current draw on Raspberry Pi it is capable to supply for about 61second. So it can withstand short power failures. If… Continue reading

Power back-up for Raspberry Pi

If you are doing continuous tasks with Raspberry Pi like logging, calculating or controlling things, then you shouldn’t rely only on power adapter. If main power fails, your device will also fail and there will be no excuse of you loose your data and work progress. In such cases you should take care of power back-up. Repairhub suggests his battery power backup system for raspberry Pi. This is actually an external circuit attached to boards GPIO power and control pins. His circuit does the following: charges battery when mains is on; generates signal to GPIO when power goes off; software detects power down and few minutes shuts down computer; after shutdown power circuit is shut off to preserve battery from discharging; pi logs events with timestamps. Circuit detects power off by using optocoupler. Signal from its output is sent directly to RasPi GPIO8. Power cutoff circuit part is constructed by using couple MOSFETs. Continue reading

Smart power controller for Raspberry Pi

One of the weakest sides of raspberry Pi is its power supply. We only get micro-USB option for powering the device. In one hand this is great feature because micro-USB chargers are becoming standard for phone chargers, so most of us already have those near by. There is another option of powering Raspberry Pi – using PGIO where you can find power pins. The real problem is that you don’t have much of power control on board – even there is no power button. Once you plug the adapter it starts to work immediately and powers off once you plug it off. Felix Rusu have designed small power controller for Raspberry Pi which gives some control. It is Attiny based board so called ATXRaspi that gives features like power button, status LED, and link to RasPi. This allows shutting down the board without need to log in. when you click the power button adapter sends command to Raspberry Pu through GPIO to initiate shutdown script and will safely turn it off. Practically you can place any commands to execute before… Continue reading