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Week 4- Set back In lab hours This week we combined each part of our circuit that was responsible to us separately and tested its function. We rebuilt the circuit we obtained on a breadboard to another two strip boards in order to make the whole system easier to carry. The circuit is shown below in figure 1. Two solar panels and the little port on Tp4056 that could be connected to the main electricity are used to charge the battery pack. When switched on, the battery pack would then generate the power into the amplifier circuit. Figure 1 As we expected to charge the phone we only need to plug it into the circuit, but it did not work. When we plugged it into an old iPhone 5 that is damaged but still could tell if it is being charged for testing, the phone reacted as its screen lit up, however, the battery kept dropping. %%%The video of the Phone reacted to the charger is presented in the next blog%%% Possible reasons After doing some research, we found it seems that it is for practi
Week 3-- Big Progress In lab hours We first tested that the toggle switches are working properly. Then as mentioned in previous blogs, one of our biggest challenges is to boost the output voltage given by the battery pack from around 3.6/3.7V to theoretically over 8V. Giles has looked into multiple ways to amplify the voltage using various chips. We have given up an original method since it is only able to function with a voltage that exceeds 7V. While our solar panels could only provide us with a constant 5V as mentioned previously. After doing some research and comparing several amplifier circuits. We later decided to include an LM2577 into the circuit and build another amplifier circuit as shown below: Figure 1 Giles has spent time calculating the value of the components we need within this circuit over the last week. As expected, we were to obtain an approximate 8V output with an input voltage of no less than 3.5V. After several attempts connecting the circuit on a breadboa
Week 2- Group meeting after the lab hours We organized another meeting after lab hours in the morning. · SC confirmed that he had finished testing and everything for the solar panels and charging circuit was working as expected. · JX confirmed battery output for 3.6V/3.7V and he and SC confirmed that the charger circuit could withstand no more than a 5V output therefore we agreed to use a 3.7 V input and model the output as 8V with a load current of 800 mA. · GC will now redesign the LM2577 chip to work with these values and put another order form for additional components, with the expectation to test his circuit on Friday 17 th February. · Project documentation was allocated for each member and is as follows: GC = project management forms SC = poster – GC and JX will communicate across designs as and when needed. JX = blog · JX will look into how the USB can connect to the circuit. · SC will look into the context an
Week 2--Problems occur What we have encountered As for the discussion last week, we decided to put two battery packs in a series, seeking to provide us with an approximate 20W charging power. Figure 1 However, we have discovered that this way the 5V charger would not be able to charge the battery packs since in parallel, it is 7.2V>5V. Jim has put up a thought that possibly we are able to charge two battery packs separately and use a toggle switch on the wire that connects two battery packs. However, this is not realistic for use as the user would need to switch it on each time we charge the phone. As mentioned in previous blogs, there exist two types of charger for an iPhone, one is able to provide a 5W charging power and the other is able to output a 20W charging power. We later compromised and decided to come up with another amplifier circuit with an input around 3.6/3.7V.
Week 2-Group meeting Our team had a meeting after discussing some detailed problems and expressing our concerns about the project with our academic advisor. The things we have covered Tp 4056 is a chip that prevent the battery pack from being over-charged as it could automatically shut down once the voltage across the battery pack reach the maximum charging value of 4.2V. Red light indicates that it is being charged and blue light would appear when finished. Tp4056 is easy to get overheated as we found out last week when experimenting with the circuits. We later discovered a possible reason that caused it could be because the input current has exceeded the required maximum current for tp4056. For maximum 1A, we have put it into work with 2.2A input. Figure 1: TP4056 During this group meeting, we recognized several more components we would like to order, including the toggle switches that are used to separate the circuit in case the battery would be charged and discharged at the same