The HC-05 is widely used as a cheap simple just works transparent Bluetooth serial link. It can be configured to be host or slave, which means you can use two of them to create a paired link that passes your UART comms over Bluetooth. Parts HC-05 Bluetooth Serial Transceiver, you want the HC-05 that is […]
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Cell balancing
When multiple rechargeable battery cells are wired in series, to achieve a higher voltage battery pack, cell balancing may be needed. A set of cells connected in series will all see the same current, whether providing it as they are discharged or accepting as they are charged. In a perfect world, if all of the […]
Measuring current
Measuring current with an osciliscope You don’t need a specialist current probe for your osciliscope as you can simply measure the voltage across a current sense resistor. This is a typical test measurement method and can also be used to measure the current of very fast pulses. A typical test for current is to use […]
BAUD Rates
Typical BAUD rates 240048009600192003840057600115200256000
IoT Connections
Mobile IoT Deployment Map https://www.gsma.com/iot/deployment-map/ Connection Options NB – Narrowband Very limited data limit. Intended for very small amounts, like smart meters etc.Better global coverage LTE-M Better for more data, but not currently forced as part of the 4G spec, so you’re down to which carrier decides to support it in each country. In theory […]
Routing USB-C PCB connection
A USB-C connecotr has two sets of data pins, the plug that will connect to it has just one pair. You route a single differential pair between the connector and your processor as normal (using impedance-controlled routing for the differential pair). At the connector, connect the differential pair to both sets of pins on the […]
DC power input surge protection
For low voltage power inputs, e.g. when using an external AC adapter or say a vehicle low DC voltage supply, electrical threats include lightning surges, ESD and external equipment switching spikes. A fuse or resettable PTC can be used for short circuit and overload current conditions. For surge and ESD protection, an MOV or TVS […]
Power delivery
USB C is able to provide up to 20V @ 5A CC pin is used for the “USB Power Delivery 2.0” single wire comms protocol. This protocol allows for much more than just power negotiations, it unlocks the advanced capabilities of the USB Type-C cable. PD messaging occurs completely independently of USB data and is […]
USB C connection to older USB devices
USB C uses a reversible connector, additional data pins and higher current capability. However, the pin usage from older USB will work just fine in many instances. Simplest connection Required:VBUS 5V inputGND 0VD+ D+D- D-Power signalling:CC1 & CC2 pin, each with a 5.1K resistor to GND. Indicates to the upstream port to provide 5V and […]
.USB-C General
Speed USB 3.0USB 3.1 Gen 1USB 3.2 Gen 1 5Gbps USB 3.2 Gen 1×2USB 3.2 Gen 2×1 10Gbps USB 3.2 Gen 2×2 20Gbps (doubles the data lanes within the cable, may well get dropped in favour of USB 4) Thunderbolt 3 via USB-CThunderbolt 4 via USB-C 40Gbps Connectors USB 3.0USB 3.1 Gen 1USB 3.2 Gen […]