IOT: The chips in your inexpensive Radio Controlled Car, TX2/RX2
The TX2/RX2 chip provided in the Radio Controlled Cars appears to be the winner when it comes to radio controlled solutions. Why? Number of super cheap Radio Controlled cars like the Thunder Tumbler is pretty big and sadly in the US after a couple of bashes into a wall the Tumbler ends up in the trash bin. Now let’s say you want to build a robot, but don’t have much money, this might be the way to go. In this article let’s explore the functionality of the TX2/RX2 and how you would use Office 365 or Azure in conjunction with the TX2/RX2.
Sure there are other chips, with onboard antennas like the ones sold on Amazon at: https://www.amazon.com/nRF24L01-Wireless-Transceiver-Arduino-Compatible/dp/B00E594ZX0/ref=sr_1_1?ie=UTF8&qid=1420499883&sr=8-1&keywords=Arduino+Radio. This pair provides functionality on a single chip with built-in antennas and you do not have to build the transmitter and receiver circuit, but at about $6 (2015 US) these are expensive units to start off with, and at the higher frequency they will be mostly line of sight. Easy to use though if you are starting from zero. Range appears to be about 120 feet, which may exceed the TX2/RX2 low power units. And frankly, these are more desirable because of ease of design and utilization, but… many people have the inexpensive RC vehicles that are broken than there are people with the nRF24L01.
The TX2/RX2, even with the added parts like the inductor, antenna and other parts, costs less. The lower frequencies have a longer range than the 2.4 gigahertz, if that is important. On the downside, you have a logistics problem as well, you have to use two different chips, one for transmission and one for receiving.
TX2/RX2 systems are easily lifted from most RC controlled cars, with the motors and LEDs, these units are pretty useful and easy to work with, but the Nordic nRF24L01 are also easy to work with. The handy thing about the TX2/RX2 is that they come fully functional in most of the inexpensive RC controlled cars and wheel vehicles. This means that you can choose to use the existing circuits or use an nRF24L01 in a hybrid mode that overrides the TX2/RX2 circuit and then pass the control signals to the power transistors. But let’s look at the TX2/RX2 circuit and how we can use it to collect information.
Why are talking about these cheap parts?
Clearly I can afford the nRF24L01, but not everyone can. Most people are able to get one of these inexpensive vehicles and an Arduino or TI Launchpad or Intel Edison. They can gently break them down and have the parts to build a robot vehicle that could collect data using inexpensive sensors like temperature, wind and so forth.
So what does it do?
Unlike the nRF24L01 it doesn’t do much: Left, Right, Forward, Reverse and Turbo, generate the RF oscillations that you need to implement a simple RC Vehicle. But in the datasheet, from Alibaba.com: you can see that the same chip provides both the transmission and receiving components depending on how you set the switch. You could mix the signals using a coding process.
Well that’s nice, but how does this work with Office 365 or Azure?
If you trying to break into engineering IOT solutions, you could do this by building inexpensive controllers that might test for environmental variables. And now you have to put that data somewhere, and you can put that data into Office 365 or Azure or OneDrive. Or you might want to set-up a hardware test jig to test your transmitter and receiver pair before you go out and run your tests.
If you are breaking down existing parts, then you might want to test the TX2/RX2 to make sure they are working after you desolder them from the circuits. In this case you could set up your test rig to run the tests automatically and then put the data up in the cloud. This might seem stupid, but testing hardware is important, and if you are going to implement a new business, this would be one way to start showing that your company is able to perform tests in a disciplined manner and to store the data. At the same time you can test these radios from the broken RC Vehicles.
Or, you could test the whole radio system, as the boards are easily removed, in that case you would send a signal from the transmitter to the receiver and then record the final results, again using Azure or OneDrive.
Conclusion
If your labor rates are low enough, then the parts in the inexpensive RC vehicles are worth more than the parts separately. When separating the parts you might damage them and testing is required. To prove your abilities as a hardware engineer you will need to show that you can use low cost systems like Office 365, Onedrive or even Azure to store your test data. In the small amounts of testing you may do, having a demonstration system that shows you are able to build a test system for recycled parts and to store that information in a useful manner online shows that you are capable of working on your own to solve a complex problem.