As usual, I end up thinking of all the different ways I could achieve my goal .... and then have a go at most of them at the same time: -
- Remote transmitter attached to the rifle, using a receiver with a graphical LCD to display the results.
- Remote transmitter with a normal 16x2 LCD receiver.
- Remote transmitter with a Jeelink/Jeenode connected to a PC running an VB application to display the data.
- As no. 2 but with a smaller 8x2 LCD.
- As no. 4 but with no transmitter and the whole thing mounted on the sensor tube.
Images below showing the received data from the Jeelink. I also receive the transmitter's battery voltage level.
To determine the energy generated by the rifle/pellet you need to know the weight of the pellet in Grains, this can be adjusted to cater for the .177 pistol or the .22 rifle or different types of pellets.
|Results from my 34 year old Diana air rifle|
|Results from my CPS CO2 air pistol with fresh Cartridge|
|Arduino Nano connected to an 8x2 LCD|
This package was quite neat and small so I got to thinking about mounting the whole thing on the aluminium tube using a step up converter so I could run the
Nano Mini Pro (Smaller) at 5V (16MHz) from one, or two 1.5V cells or a small lithium ion cell.
To do this as neatly as possible I decide to dust off the Eagle PCB layout tools and do a PCB, after all it's only around £10 for 10 off 5cm x5cm PCBs.
|Rendered view of the PCB with LCD|
|Rendered view of the back of the PCB showing the Mini Pro and RFM12B|
It's a bit of a squeeze but I got the LCD on one side the Arduino Mini Pro on the other and even got an RFM12B 868MHz transceiver on there, I couldn't help myself, I also added a couple of spare switches at the bottom of the display and a space for a temp. sensor (DS18B20) this will give me some alternative uses, remote temp monitoring/display etc.
There is also the 5V step-up converter on there, it's one of these.
More to come ....